Tutorial - Nerf Maverick Aimtrak Mod with Solenoid Recoil

[captaincatalyst]

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Disclaimer: This tutorial involves soldering and the modification of electrical components.  You follow these directions at your own risk.  There is a risk of electrical shock (I don't mean to scare you because if you aren't doing something stupid, you won't be shocked by, much less even feel, the electricity coming out of a PC power supply.).  There is a risk of bodily harm when using the tools mentioned in the tutorial.  Just be careful and you should be able to avoid injury.  There is a risk of burning down your home with the soldering iron and hot glue gun.  Don't leave them on and unattended.  There is a risk of damaging your PC power supply, your PC, and your Aimtrak unit.  Just be careful and don't blame me when you break something, hurt yourself, or burn down your home.  Also, I make no guarantee that any of this will work for you.  The tutorial is available for educational purposes and documents to the best of my recollection what I did to get an Aimtrak added to a Nerf Maverick with the addition of solenoid recoil.  Feel free to use this tutorial as an inspiration for your own projects.  You do not have my permission to post these pictures or the text elsewhere on the Internet.  If you wish to do so, seek my permission and give credit.  This tutorial is not to be used for monetary gain.  That is to say, don't use my tutorial, schematic, or code to start manufacturing guns for sale.  If you made a gun using this tutorial and end up selling it later, that's fine.
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I already had most of what was needed, so I can't really say how much everything would cost if you buy them outright. 

I want to caution that this project does require some advanced soldering skills as you will actually have to de-solder and detach the camera board on the Aimtrak and connect it back with wires.  The solenoid recoil integration requires the ability to program a microcontroller, however you can get a programmer and microcontroller for pretty cheap.  I will provide my PicBasic Pro code and a HEX file that you can write directly to the microcontroller if you have no desire to mess with the code yourself.  Having said all of that, I was not an Electrical Engineering major by any means, and I don't really know many specifics about the parts I'm using.  I have studied Computer Science, but actually got my BFA in Sculpture.  I'm sure an EE major would find all kinds of problems in my schematic and the way I am approaching the issue, but it works for me (However I would be interested in feedback from anyone who does know about this stuff.).  I have figured out soldering and microcontrollers simply by researching and experimenting.  Play around with soldering and get some in-depth step-by-step microcontroller project books.  It will take time, and you will certainly mess stuff up, but as long as you're being safe, you'll hopefully be learning all the way.

There are a couple of issues to deal with when integrating solenoid recoil.  First, you need 12-24v of DC.  You can't get that from the USB port.  Second, at this point anyway, I don't think any of the input pins on the AimTrak can be configured as output pins.  If that ever does happen, the microcontroller can be eliminated altogether, and the AimTrak could control the recoil.  At any rate, I decided to create a parallel circuit for the solenoid controlled by a microcontroller that does not actually interact with Aimtrak at all.  In my solution, when you pull the trigger on the Maverick, 2 buttons are actually pushed.  One for the AimTrak trigger, and one for the microcontroller input to power the solenoid.

Here are the parts and tools needed for the project:

Basic Tools:

Soldering Iron w/ stand and wet sponge
Solder
Flux
De-solder rope (or any other means of de-soldering)
Wood block (optional - I like to solder on top of it so I don't mess up my table)
Wire strippers (capable of stripping 26 AWG wire)
Needle-nose Pliers
Scissors
Rotary Tool w/ cutting disc, sanding bit, and small sanding/cutting bit
Hot Glue Gun w/ glue sticks
Screw Driver (mainly small Phillips-head needed to open the gun)
Multimeter tool
Super Glue

Not pictured: Drill and various sized drill bits (specifically 15/64", 5/32", 3/32" bits - Make sure the 2 smaller ones are meant for drilling metal)
Not pictured: Rubbing Alcohol (for cleaning up flux)
Not pictured: Old Toothbrush (for cleaning up flux)
Not Pictured: Electrical Tape
Not Pictured: Small Vice (came in handy when drilling the rod mentioned below)
Not Pictured: File

Main Maverick - Aimtrak Ingredients:

AimTrak unit w/ Mini USB adapter and 4 wire harness for trigger switch and AUX button
USB extension cord (The ones that came with my AimTraks failed, so I highly recommend getting others.)
Heat Shrink Tubing (optional and I often forget to use it)
Wire - roughly 26 guage (pulled mine from an old CATV or USB cord).
Nerf Maverick (obviously)
Plastic strap that was holding the Maverick in the packaging (yes, we're recycling)
A piece of cushion foam or maybe a piece of sponge would work (probably optional)
Cherry Micro-switch (the kind used in arcade buttons)
Low profile surface mount tactile push button (for optional but recommended auxiliary button)

Not Pictured: Flat Clear Plastic suitable for cutting a lens (optional)
Not Pictured: DIY car window tinting for tinting the lens (optional)
Not Pictured: 1/2" Braided Nylon Wire Casing (optional)
Not Pictured: Heat Gun/Hair Dryer (for shrinking heat shrink tubing)


Solenoid Parts for Recoil (Optional)

12-24v Powerful Solenoid (ordered mine from http://www.goldmine-elec-products.com/prodinfo.asp?number=G16036 though they aren't very quick to process orders and you have to order $10 minimum.  I ordered extra so I have replacements if I need them.)
Wire - 26 gauge (taken from CATV cable - you need 4x wires as long as or longer than the length the gun will be from the computer)
PC power supply
4 pin Molex adapter to plug into the PC power supply (optional because you can hard-wire if you want)
8-pin PIC Microcontroller (I'm using 12F629 - make sure to get the PIC12F629-I/P configuration.)
Programmer for Microcontroller (I'm using a JDM programmer)
Prototype PCB
4x 2-Terminal Connector Terminals (optional as you can hard-wire)
8-pin Socket
Transistor - (I'm using TIP120 Darlington Transistor)
Heat Sink for transistor
Diode (I'm using a IN4001 diode, but I don't think it matters what kind.  It came from a pack called "Assorted Rectifier Diodes" from Radio Shack.)
3x Zener Diodes (I'm not sure if it matters, using "IN914-Type Diodes" that came in a pack from Radio Shack.)
.1uf capacitor
4.7K Ohm Resistor
10K Ohm Resistor
330 Ohm Resistor
LED (optional but recommended for troubleshooting)
Breadboard and wires for testing (optional but highly recommended)

Not pictured: Small push button (This was harvested from a broken portable DVD player, but hopefully you can find a similar solution.  It's very small and has a relatively long plunger part.)
Not pictured: Roughly 5/32" diameter metal rod cut to roughly 2" long (I had some cold-rolled stainless rods from another project, but I think you can pick up cheap rods at Lowes or Home Depot.  The actual type of metal doesn't matter.)
Not pictured: Software for Programming HEX files to Microcontroller
Not pictured: Software for compiling Pic Basic Pro code (optional if you want to modify the code and change the solenoid holding interval, etc).
Not pictured: Sharpie (if you want to mark stuff before cutting/removing it)

Be back soon with updates, and hopefully better pictures going forward.

Note: Updated/corrected all parts and tools used.
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Here's a picture of the insides of the proof-of-concept Maverick compared to stripped insides of a new Maverick.

Tutorial Part 1: Preparing the Maverick for an Aimtrak

Take your Maverick out of the packaging and inspect it.  You've got a revolving chamber that turns when you pull the trigger and a sliding part (looked it up and think it's called the "slide.") that you can pull back.  The size is pretty perfect for an arcade gun.  Image holding that and shooting zombies, aliens, bad guys, and deer.  Well if you put in a bit of work, you'll be doing that in no time.


Lay the gun so that the right side is up.  All the screws are on this side.  Use your small Phillips-head screw driver and get to work on unscrewing everything.  Start with the slide.  It has 3 short screws and the rest from the gun are longer.  Just remember this for reassembly. 


The slide should be pretty easy to pull apart.  A spring will be released when you pull these apart, but don't worry because it's screwed into the inside of the gun so you won't lose it.


The gun should pry apart with a bit of force from your hands.  I don't recommend putting anything in to pry it because you'll likely damage the plastic.


Take out the parts shown.  They should just pull right out because they aren't screwed in or anything.  You can discard these.


The barrel will pull right out.


Hopefully you can see all the parts I marked green (I might go back and modify the picture to accentuate these spots).  These will need to be cut out.  Notice that the barrel has a flat underside.  The cut we need to make will be on the top back side of the barrel.  I recommend using the smallest abrasive bit you have for your rotary tool, and be careful not to let the rotating base of the tool touch anything as you work because it will mess up parts of the plastic you didn't intend.  My bit was small and cylindrical, but a spherical bit would be fine. 


Here's what it looks like after that stuff it cut out.  Also, I forgot to mention that the revolving chamber can just be pulled right out.  You should probably do that before cutting, just so it will be out of the way.  In fact, it can stay out until you're finished and ready to reassemble.


Take both halves of the shell, put them back together, and look at the bottom (the butt?) of the gun.  Our wires need to come out of here.  Use the split as your center line and drill a hole where you would like to see the wires come out.  I recommend probably a half inch or less from the back.  I'm pretty sure I used the 15/64" bit, but looking at the bit right now, it does seem small... You can always make the hole bigger if you need to.


Here's the hole drilled.


So we've done most of our work on the left side.  Now take a look at the other side and note the parts I've marked here.  Same deal as before.  Use the rotary tool.


Here's after those parts are cut.


Unscrew the trigger and lift it off.  There is a spring looped onto a hook on the trigger, but you can rotate the trigger out toward you to unhook it.


Just to show, here's where the trigger is when it's pulled all the way back.  We want this trigger to push the button on our Cherry switch, but there obviously isn't enough room directly behind it.  We'll need to put the switch about where I'm showing you. Don't glue it down yet! This is just a demonstration.  We'll need to find a way to make the trigger push the button...


That's where the plastic strap comes in.  I noticed on my most recent Maverick purchase that it has like garbage twist ties holding it in which wouldn't work here.  The plastic straps are really just thick wire ties, you might find one of those somewhere.  If you did have the plastic straps, it should have a few L shape bends in it that we can make use of.


Put the trigger on the track and push it back to its original position.  Make a mark on the orange trigger where it meets the yellow of the gun casing.  If we add anything onto the trigger, we need to make sure it doesn't go past this point or you will obstruct the trigger from returning.


Pull the trigger back off and cut the plastic strap to approximately the length you will need.


We'll need a screw... take the one in the center of the picture (If I remember, I'll modify the image to highlight it.).  It's the one that would be above the trigger if it was on the track.  This part will stay in fine without the screw.


Take your small drill bit (3/32") and drill a hole toward the back of the bottom of the trigger.  Make sure to stay centered and only go in as far as the length of the screw you took out in the last step.  Also drill a hole in the plastic strap where it will attach to the trigger.


Use your screw driver and screw in the screw.  Just keep pressure on as you're screwing and it will thread the hole.


Attach the plastic strap.  You can also super glue it for extra re-enforcement but it's probably not needed.  Also if you just leave it with the screw, you can make adjustments later if needed.


If you put the trigger back on and place the switch down in, you'll notice the switch doesn't meet up with our new piece.  The switch will need to be raised. (You might also be able to rotate the plastic strap downward.  It's up to you.)


I cut a piece of cushion foam to stick under it to raise it.  Don't glue it down yet.


If you want to disable the rotating mechanism, take this part out.  I recommend disabling this mechanism because it causes the trigger to lock up sometimes and makes it harder to pull the trigger.  If you're having to pull this trigger a lot, your fingers will thank you for making it easier.  It's what the trigger attaches to.  You should be able to pull it back and pry it up a bit to pull it out.  Notice the raised part on the end. 


Shave that part off with whatever tool you choose.  I think I used my file.  Then slide the piece back in where you found it.

[captaincatalyst]

Part 2: Aimtrak Preparation


Notice that the Aimtrak is a little too long to fit properly in the barrel.  If you don't want to have to de-solder, I suppose you could modify a bit of properly sized PVC pipe to make the barrel longer and just put the Aimtrak there.  That's not what I did.


The camera board, the board that's on the front of the Aimtrak that's bent back a bit, will need to be removed.  Take a look at all the solder points before doing anything.  Here we have the 4 in the front.


4 behind it. (Note the one to the far left is larger than the others.)


8 on the bottom of the Aimtrak.  The 8 on the bottom actually connect with the 8 on top, so we're really only taking about 8 solder points, however you will have to de-solder all 16 points to get the camera board off.  I can't really give pictures to show you how to desolder, just make sure to be careful and don't let your iron touch anything else.  I usually dip the tip of the de-solder rope in flux, place it on the point I'm de-soldering and touch my iron to it until I see the solder melting and getting sucked up into the rope.  Cut the end of the the rope, dip in flux and move on to the next point.  After you've done them all, double check to see if there is any more solder you can remove.  Be especially careful in the front of the unit when you're de-soldering under the camera lens.


Before actually removing the camera board, cut a small scrap piece of plastic so that it is about as long as the Aimtrak and has a straight edge.  Line the straight-edge up with the bottom of the Aimtrak and trace the angle of the bend in the camera board.


Do it on both sides, tracing the other side of your plastic for the other side.  We'll be able to use this plastic to build a new platform for the camera board to sit on.


Go ahead and cut the plastic down so that it's about as high as the camera board.  Make sure it lines up with the angle of the camera board.  If not, make adjustments until it does.  Check both sides with their respective traced angles on your plastic piece.


Once you've de-soldered, with a little bit of force, the camera board should be able to bend forward a bit.  Then you should be able to pull it up and out.


Here's the detached camera board.


Cut 6 thin guage wires (think mine came from a USB cord or something) about 2-2.5" long.  Maybe go longer and cut later if you want.  Strip both ends on all the wires, add flux and put some solder on both ends on all the wires.  Make sure if you are using the same color of wire to add marks on both ends to identify them.  Like one wire has one mark on both ends, the next wire had 2 marks on both ends, etc.  This will help identify the ends when you're soldering them to the boards.


Conveniently, even though there are 8 solder points, only 6 are used, so we've only got to solder 6 wires to make this camera board work.  Solder the first three on the front as shown, skipping the second solder point.


Solder the other three on the back as shown, skipping the 4th solder point.


Imagine the camera board was sitting back in that slot.  See where the solder points would line up and wire everything back to the Aimtrak accordingly.  After soldering, clean up the flux on the camera board and the Aimtrack with rubbing alcohol and and old toothbrush.  Let the alcohol dry before doing anything else.


Close to the Aimtrak board, I added a wire tie and hot glue for security.  I recommend not actually hot gluing over the solder points in case you need to access them again at some point in the future.  Go ahead and test to make sure the Aimtrak still works.  Check your wiring if it doesn't work.  I don't really have any other troubleshooting tips.  Hopefully you didn't break it.


Here's where the Aimtrak will end up sitting.  Our wires will snake down through the cut we made in the barrel.


The camera board should be able to bend up on it's wires.  Cut a small rectangle of plastic for the camera board to sit on.  Hot glue its wires to this plastic.  Then line up your plastic that you cut to measure the angle of the bend in the board, and glue it all together, making sure the camera board bends back and that angle.  (Sorry I didn't take a picture of the end result...)


(Note: Before proceeding with gluing the camera board into the barrel, make sure to use the barrel to trace a circle on some hard, thin, clear plastic for your lens.  I used the plastic from a CD case.  Go ahead and trace the lens, cut it out, clean it up with your sanding bit on your rotary tool, and make sure it fits the barrel.) Here you can see the camera board placed inside the barrel.  Notice that it is raised up a bit.  I filled it in underneath with hot glue (just enough to keep it supported).  Make sure to seat it in barrel about a millimeter or two back from the slits cut on the sides of the front of the barrel in order to make sure that our lens will fit in without having the edges visible from those slits.


Here is a side view.  Notice that it is backed up behind those side slits in the front.


Here you can see a clear lens and a tinted lens.  Trace a circle using the barrel on some hard, thin, clear plastic for your lens.  I used the plastic from a CD case.  Go ahead and trace the lens, cut it out, clean it up with your sanding bit on your rotary tool, and make sure it fits the barrel.  For tinting I simply started with the clear lens and added DIY car window tinting.  I ordered it on ebay for pretty cheap for a small portion.  I didn't think about it in time, but you might even be able to get scraps from a business that applies tinting.  You don't need much at all.  After applying it, I simply used a razor to clean up the edges.


For mounting the lens, I simply forced it in and it stays.  No adhesive is needed.

[captaincatalyst]

Part 3: Buttons and Switches


Take a look at the slide.  Conveniently, it has an orange button on top.  I have no idea why this button is there, but we can make use of it for our Auxiliary button.


The button and spring should pull right out.


I wired some short (3" maybe) leads onto a low profile tactile switch (It came from a control board on a broken portable dvd player, but you can order some SMD buttons on eBay or something.  Just make sure they're low profile at 1mm or less high.).


Flip the orange button over and shave off the circular part in the middle.  If you decide you need to, you might also shave off the 4 nubs in the corners.  I recommend waiting until you've seated your switch and see if those get in the way.


I used my soldering iron and some discarded orange plastic to melt a nub into the center.  I had to make adjustments to make sure it was going to push the tactile switch and still have room in its slot.


Seat your button into the slot with the leads pointing towards the back of the slide.  I hot glued it in, but make sure you're getting it as low in the slot as possible, and it's not sitting high up on a glob of glue.


Slide the orange button over top of it and see if it will push the switch.


Close the slide and make sure the orange button still pushes the switch.  Make adjustments (raise or lower your nub in the the middle) as needed.  Set the slide aside for now.


Here's a view of the leads that will need to be attached in order for the AUX button to work.  This is just for reference as they will be connected in a later step.  You can go ahead and connect them now if you won't be adding a solenoid.


Let's focus on the Cherry switch for the trigger and the extra button for the solenoid if you're adding it.  You can see the smaller switch I'll be using.  I have no idea if these have a specific name.  I simply found some on the PCB of a broken portable DVD player and they worked perfectly for what I'm trying to do.  Hopefully you can find something that will work, or another way of pushing two buttons at once with your trigger.


If your Cherry switch is oriented the way mine is, you can pry the top off pretty easily.  Take a look at the insides.


When you push in the button, you see there's an empty space toward the top and some metal that kind of bends up into that space.


If you have a button that will fit, you can cut out a space for it using your rotary tool and a small bit.  Then when you push the Cherry switch, the second switch is triggered as well.  I hot glued it in place so that I could make adjustments.  You want to place it so that it's making a connection at nearly the exact same time the connection is made when you push the Cherry switch.  Get it as close to being the same time as possible or you might end up triggering the solenoid sometimes without firing or the other way around.  Of course if you ultimately pull the trigger back all the way every time, this probably won't be an issue, but I still recommend getting it as close as possible. (Note:  I added roughly 2-3" leads to the switch before installing it.)


After the modifying the Cherry switch, you can go ahead and install it in the gun.  I hot glued the cushion foam down, and then added a bit of hot glue on top and placed the switch.  I made sure its back went all the way to the back of the gun where it presses up against one of the gun's structural supports. (Take a look a the next picture for a better view.).


Make sure when you pull the trigger, it actually pushes the button.  Notice that I am not actually pulling the trigger all the way back.  I prefer for the button to be pushed in a bit before the trigger is all the way back so you fire and get the feedback as the trigger is coming all the way back.  The flexibility in the plastic strap will allow for this and keep the button pressed even when the trigger is all the way back.  Do you want you prefer.


Go ahead and put the barrel and Aimtrak in.  I added a bit of hot glue to keep the barrel in place.  I don't recommend gluing the Aimtrak unit down in order to keep it accessible if you decide to add more buttons later.  It doesn't shake around or anything, so gluing isn't needed.  Plug in the USB cable and snake the cable through as shown.  You might need to make a few more cuts in the plastic of the gun to get the cord to fit down properly.  Also snake the wires for the trigger button along the same path and plug them into your Cherry switch.


Make sure the gun will close with those wires in it.  Make cuts and adjustments as needed.  Maybe even glue down the wires in some spots.  If you're not adding the solenoid, you can just wire up the AUX button and re-assemble the gun for a working Maverick Aimtrak gun sans recoil.

Part 4: Adding The Solenoid


Here's the solenoid I used.  Take a look and see how things work.  Notice that you can push the plunger (not sure if that's what it's called) in and the spring will make it return.  You can also completely pull out the plunger.  Put it back in and go ahead and use your PC power supply and touch the +12v and ground to the two leads on the solenoid (12v to one and ground to the other, it doesn't matter which).  Don't apply power for more than a second or two at a time or it will get very hot very quickly.  Does it do anything?  The spring may be extending the plunger further than the 12 volts can power it to return.  Try pushing it in a bit and adding power.  Does it do anything now?  Hopefully so or you may have a bad solenoid, or maybe you're not doing something else right.  I don't have any troubleshooting tips beyond try again and with another solenoid if you have extra.


The solenoid is attached to a bracket that will keep it from fitting in the Maverick.  Also the leads come up a bit too far.  These are going to have to go...


Using pliers, you can break off the plastic holding the external leads.  Don't worry if the the metal leads come with it... At least don't worry much.  You should be able to get to the leads with a little digging.


Cut off the bracket with your rotary tool and the cutting disc.  Cut as close to the body of the solenoid as possible so that very little remains.  If not, you'll have more to sand off.


Turn it so that the front is facing you.  We need to round it off a bit.  Notice the spots I marked in green.   I guess I didn't take a picture of the immediate result, but you can shave those parts off with a sanding bit on the rotary tool.  You can leave a ridge on the solenoid in this area, but it just needs to be rounded off.


Place the solenoid in the gun and push it all the way back.  Make a note of where the ridge is touching down.


I used pliers and broke out a spot for the ridge.  If there is anything left toward the back of the gun that is raising the solenoid up, it might need to be removed.  Hopefully it's obvious what I've done here.  If not, look at your Maverick and compare it to the picture.  Make the same change on the other side of the gun as well.


Put the solenoid in and push it all the way back.  Then close the gun and make sure it will actually close.  If you look at the back of the gun, you should see the back of the solenoid sticking out a through the hole.


Take the solenoid back out and add wire leads (probably 7-8") to it by soldering them on.  I actually used a thicker gauge wire here like 22 gauge, but thinner wire should be fine as long as it's rated for 12-24v and isn't so thin it would melt under a bit of heat.  If you can't find where to solder to, you might have to dig into the plastic a bit.  I actually hard a difficult time with one of mine and ended up using the soldering iron to melt a bunch of the plastic and eventually found both wires to solder to.  When you solder your wires, make sure the solder on both points does not touch the outer casing of the solenoid.  Make sure your wires are flat against the solenoid and facing the front.


I added hot glue to fill in the cavity I created, and I added electrical tape around the body of the solenoid to secure the wires a bit more.


Place the solenoid in as shown and snake the wires through the gun.  I added a bit of hot glue along the side of the solenoid to keep it in place.


Pull the spring off the solenoid's plunger and discard it.  Be careful when removing it because it's sharp on the ends.  Place the plunger in the solenoid while it's seated in the gun.  Alright, we need to find a way to get this plunger to pull the slide when the solenoid is activated.  Notice the rod in the slide that is poking out above the solenoid's plunger.  I think we can make use of that.


Use your file and file out a small notch in the plunger in the same spot at the picture.  It doesn't matter how the plunger is rotated.  Just make sure to make your notch about the same distance as I did from the front.


Use that notch and cut a hole the same width as your metal rod that we found/bought for this project.  Start with a much smaller drill bit and make a hole through it with that first before using the larger size.  Make it as centered and perpendicular to the plunger as possible.  You might even clamp the plunger down in a vice so you can avoid injury to your hands.  My drill bit is 15/64" and the rod is able to slide through it with little friction.


Make sure the rod can slide through the hole with little resistance.


Now we need the rod from the slide to go through the rod we added to the plunger.


Same deal as with the plunger... File a notch in the rod and drill a hole so that the slide's rod can fit through it.  You can pull the rod straight out of the slide pretty easily with some pliers.  Just don't break any plastic while doing it.  You have less room to work with here so hopefully you have enough rod to work with if you make a mistake.  Just make sure the hole you're drilling is towards the top and you've got about 1.5-2" left below the hole.  I used a 3/32" drill bit.  The slide's rod barely fits in the drilled hole at this size and I actually had to hammer it in.  A slightly larger hole probably would have been better but I couldn't find all my drill bits.  Good luck with this one.  I definitely recommend clamping this one down before drilling.  I actually cut one of my fingers with the drill when doing this by hand.


Here you can see everything kind of put together.  It's OK if everything slides around through the holes when it's put together, and that actually works to our advantage.  You can now imagine when this is all put into the gun, the plunger should pull the slide with it.  Try to put it in the gun and you'll notice that the rod you cut is a bit too long.


You'll need to cut some of your rod off at the top and the bottom.  Notice the parts I marked in green.  At the top, you should actually round it off a bit to meet the curve of the slide's rod.


Now put it all in the gun and it should fit.  Make sure to loop the return spring to the slide's rod.  Since our rod can slide through the plunger, it should be pretty easy to rotate everything around as needed to get it all installed.  Attach the left side of the slide back to it. (Go ahead and wire up the AUX button if you haven't.  I did it with solder and electrical tape.)


Here's what it looks like with everything on the inside assembled.


Here's an image showing how far back the slide will go.


Make sure the gun will close.


Make sure you can slide the left part of the slide back with no resistance.  Note that it will only go as far back as the plunger goes into the solenoid.  Go ahead and add the right side of the slide to it and make sure it can still slide with no resistance.  If there is resistance, you'll need to make adjustments to the rod like rounding off the top more or make sure it's not somehow being forced into the side of the gun causing friction.

[captaincatalyst]

Part 5: Recoil Control Board

So I've taken pictures as I was assembling the board, but it isn't very obvious what was wired to what.  I will add a schematic that you can hopefully follow to make your own.  The way I laid them out on the PCB was simply to give it as small of a footprint as possible since I thought I would end up storing it in the gun itself, but have opted to keep it external since it still ended up being a too big.  If I had gone with a custom PCB and surface mount parts it could easily be made much smaller, but keeping it external will allow for it to be stored in an accessible part of the cabinet for adjustments and repairs as needed.


Here we've got the terminal connectors and the prototype PCB.  I got these parts from Radio Shack.


I lined the terminal connectors along the edge of the PCB.  I kept them all in a line and designed the layout around these.  This should allow for easy connection of wires.  Nothing is soldered yet.  It's just sitting there.


I recommend labeling the connectors as follows.  Two will be for our +5v and GND from the computer power supply to power the microcontroller.  Two for our button that the trigger pushes that will activate the recoil.  Two for our +12v and GND from the computer power supply to power the solenoid.  Two for our solenoid.


Put the 8-pin socket in.  I faced it so that the front part with the rounded notch cut out is facing toward the terminal connectors.  Still no soldering yet.  This is more about placing parts and laying everything out.


Here I've placed many of the components.  It's important to follow the schematic and place components near other components they will be connecting to.  No soldering yet.


Here's a top view.


Added wires to make some connections.  Still no soldering.


Another top view. Still no soldering.


Here's a bottom view.  Go ahead and start soldering some parts down if you are sure of their placement.  Maybe a good idea would be to follow one path at a time using the schematic, following from the pin on the microcontroller all the way to where that line ends.  Once a component is soldered in, you can bend the excess wire leads until they break at the solder point.  Alternatively you can use some small wire snips if you have them.  I usually bend them around until they break.  Just make sure you didn't disconnect the solder joint.  Re-solder if needed.


Here I've added the transistor with a heat sink.  I added this last since it sticks up so far it would hinder soldering on the bottom when you flip the board over.


Here's a view of everything soldered on the bottom.  Notice that I've added some wires to bridge connections.  Your layout will likely need to include wires as bridges since not everything will be right next to something it should be soldered to.  Wires can bridge connections from above or below.  It's just a matter of ease and preference.  I've wired above and below.  Make sure not to allow your solder to jump from one point and connect to another that isn't supposed to be connected.


Here's another view.  Make sure to clean up the flux with alcohol and and old toothbrush.  Give it a good scrub to make sure nothing is connecting between solder points that isn't supposed to.  Flux shouldn't be electrically conductive, but I've run into problems that were solved by cleaned up the flux.


You can go ahead and wire in your power.  I've made use of a molex connector for easy connection to the PC power supply.  Also, when you're ready, connect long wires to your solenoid leads in the gun, and the solenoid button leads.  These wires should span the length of your USB cable with the extension cable attached.  I used some wires harvested from a CATV cable.  Once you have those wires in place and connected to the leads in the gun, you can screw them in to the appropriate terminal connectors on our recoil control board.  Your microcontroller will still need to be programmed before you can test.


Part 6: Finishing Touches


I recommend hard wiring your USB extension cable to the USB cable coming out of the Aimtrak.  If you're lucky, the wire colors are the same and actually line up at the right spots.  Both of the extension cables I used had odd colors, so I had to follow a USB cable pinout and trace the wires to the points on the USB connector to see what was what.  I used my multimeter to test the connections on my wires to the USB plug.  You can find USB pinouts at this page:  http://pinouts.ru/Slots/USB_pinout.shtml  I soldered my wires together and then wrapped them in electrical tape to make sure they wouldn't touch each other. (If you remember beforehand, you can put a small length of heat shrink tubing on the cable before you solder so that you can put that over everything when you're done.)


Luckily I remember to add the heat shrink tubing before soldering together.  I used a hair dryer to shrink it.  Even with the tubing, you will still need to wrap the individual wires in something like electrical tape to make sure they don't make contact with each other.


After your USB cable is ready, you can start thinking about concealing it and the extra wires for the solenoid and recoil button.  I recommend this braided wire casing.  I used 1/2" braided nylon tubing I found from a seller on eBay.  It's expandable and easy to use.  It might be best to cut the length you need before using it.  I didn't, and cut it after I had snaked my wire through.  It made it a bit more difficult, but it's still possible.  Also it will fray where you cut it, but you can use your soldering iron to melt the edges where you cut to avoid fraying.  It will make a mess on your soldering iron tip, but you can file it off once it's cool.


You can see that I've taped the 4 extra wires to the end of the USB cable.  Make sure to do this or you will have a hard time getting everything through the casing.


Here's a picture of how wide the casing can expand to.  If you hold it in one spot and push it towards another spot on the casing it will expand like this making for an easier time snaking your wire through.


Once you get the tubing all the way up to the gun, I recommend adding a wire tie just above hole in the gun.  I also added a wire tie at the other end near the USB plug.  The 4 extra wires are sticking out a bit more and plug into the terminals on the solenoid control board.


Provided you've programmed the microcontroller, you can close up the gun, plug everything in and you're finished!  Note that if you have two guns, you will need to make 2 recoil control boards.  If you want to paint the gun, it's probably better to do that before adding the Aimtrak to it.  You can also easily sand off any Nerf text on the gun which I'm doing on my two guns.  I do plan to paint them, so I guess I'll be stuck stripping these parts out and adding them back...

Part 7: Solenoid Recoil Control Board and Programming

------------------------
Disclaimer: You have my permission to use this schematic and code for your own purposes as long as you aren't selling it.  Now if you end up incorporating this into your gun and sell the gun, that's fine.  Please do not post either of these elsewhere without permission and without giving credit.  Feel free to modify the code and use the schematic as a starting place for something larger.  I make no guarantee that this schematic will work for you.  I did my best to create it based on the components I soldered onto my prototype board.  Build it all on a prototype breadboard to make sure it works for you before committing to soldering.  I will do my best to give support to those building these for there own use, but I cannot guarantee I will have time to do so.
------------------------


Here's the schematic.  I didn't use standard symbols for all components in order to keep it as simple as possible for beginners.  Diodes are directional.  In the schematic they are shown as a pointing arrow.  Your zener diodes should have a black mark on one end, and the rectifier diode should have a silver mark on one end.  If you imagine your diodes as a pointing arrow, they should be oriented such that the arrow would be pointing toward these marks.  I (mostly arbitrarily) color coded the different lines in the schematic.  These lines should not touch any other lines.  You will see a couple places where these lines cross in the schematic, but there is an arch at these points indicating that the lines are not actually touching.  I recommend when you're building your own, complete one color line at a time.  If you add the LED, it will blink every time the trigger is pulled.  I think this is very helpful when troubleshooting.  If you see a blink, but the solenoid does nothing, then there's probably an issue with the way the transistor is wired.  If you see no blink, there's likely an issue with the microcontroller or the way it was wired.

Attached is the HEX file you can program to your PIC 12F629.  Just rename the attached TXT file to HEX.  I use a JDM programmer and IC-PROG found at http://www.ic-prog.com/.  You shouldn't have to do any programming or compiling of your own if you want to use my settings.  The way this is programmed, if you pull the trigger, the solenoid retracts once for 40 miliseconds and then is released.  Even if you hold the trigger in, it will still only recoil once.  I do plan on programming it to make it recoil if you hold it in, maybe with an automatic mode that will be activated with a switch, but for now it's one trigger pull, one recoil until you release and pull the trigger again.

If you have the ability to compile PicBasic Pro Code, here's my source code.  It's a bit dirty and there are no comments.  I was experimenting with what pins can be inputs and actually set up 3 as inputs that all do the same thing and 2 as outputs that do the same thing.  What this means is that if you use this code, you can actually wire your switch into one of the other pins and it will probably work the same.  The code can be changed to allow for an additional switch if you want an automatic mode, etc.
-----------------------------
b1 var byte
b2 var byte
b3 var byte

b1=0
b2=0
b3=0

INPUT GPIO.0
INPUT GPIO.1
INPUT GPIO.2
OUTPUT GPIO.4
OUTPUT GPIO.5

low GPIO.4
low GPIO.5

Main:
button GPIO.2,0,255,0,b1,1,presstog
button GPIO.0,1,255,0,b2,1,presstog
button GPIO.1,1,255,0,b3,1,presstog
goto Main

presstog:
 HIGH GPIO.4
 HIGH GPIO.5
 PAUSE 40
 LOW GPIO.4
 LOW GPIO.5
goto Main

end
-----------------------------

That's all I've got.
Good luck!

[captaincatalyst]

This should have been the first post, but whatever...

Hello everyone,

I am new to the forum and kind of new to DIY arcade cabinets.  I've gotten a lot of inspiration from this board so wanted to give back.

About a year ago I modified a cabinet I got for free from someone on craigslist and installed a JAMMA harness, my own control board, a NEO GEO board and an LCD screen as a stepping stone to my ultimate plan of building my own cabinet for emulation.  My discovery of Aimtrak kind of pushed me over the edge on getting started again.  I've built a (probably way overpowered) computer for the task and bought 2 aimtrak units.  Part of my original cabinet mod included hacking the PCBs of a PS/2 keyboard and 3 USB keyboards so that the control board can interface with the computer.  So at this point, I just have to finish up my Aimtrak guns, build the cabinet, and get everything I want installed.

I chose the Maverick because you can get them for about $10, they're pretty nice looking, perfect size for the task, have a sliding top part (don't know what that's called on a real gun...), and you'll find all kinds of nice images out there of awesome modifications people have done to them.  I also really like the revolving feature, but ended up having to disable it since it causes the trigger to lock up sometimes.

My goal with the tutorial is to hopefully inspire some other people to get started and maybe help others to add features to their guns they might not have thought about.  The main feature I wanted in an arcade gun was recoil.  I tried to find a good tutorial, but really only found people talking about how they wanted it and no one ever really showing you how to add it.  I'm talking recoil with a solenoid and not a vibrating motor.  I've also seen people mention the Maverick as good for an Aimtrak conversion, but again, no tutorials or even pictures of a working unit.  If any of that sounds interesting to you, you'll be glad to know my tutorial shows how I made a working Maverick with recoil.

Since I've now got a pretty good grasp on the first Maverick Aimtrak installation, I photographed my second build for the tutorial.

[Nips916]

You Sir, are a gentleman and a scholar.  Thanks. 

[jipp]

this should be a sticky.. amazing documentation.  im a long ways from modding my own gun.  but i do plan on buying a aimtrack setup this month.. im just gonna go with the default setup/shell for now.. then go from there.  will def be using this thread for reference when i feel im ready and find the right gun i want to use.  i personally enjoy working with wood so whatever gun i pick will need removable scales ( handle grips ).. so i can make some out of exotic wood.

chris.

[Bender]

AWESOME!!!!!!!

damn it, now I have another project on my never ending list

[JohnEDollar]

this should be a sticky.. amazing documentation. 

+ 100 on that!

Excellent tutorial, CC. Well written documentation with lots of pictures.

(I'm not currently incorporating light guns in any of my (future) project, but when I do .... )

Welcome to the BYOAC forums, and Happy New Year to all! 

- John

[drventure]

Now, see, you just went and did what I've been aiming to do for, well, ever!   

Excellent job! I'd actually bought a maverick and another rotating barrel nerf for this purpose, then went and steampunked em for fun.

So I picked up a couple other guns to use for this very purpose. But I'm considering a wiimote mod so there won't be wires.

Still, excellent job.

I love how you repurposed that button on top (I believe that's actually a clip that a "site" snaps into), and demounting the camera so it fits in the barrel was awesome!

 

[SammyWI]

  Very nice write up.  I'm especially interested in the solenoid recoil setup.  Very cool.

[captaincatalyst]

After proof-reading, I noticed some errors and corrected them.  There are probably still some errors.  I also updated some steps to hopefully be more clear.

Thanks to everyone who has given feedback so far.  I'm interested in getting feedback from anyone who actually uses the tutorial.  Let me know if something is not clear. 

Also if there are any EEs that would look at the schematic for the solenoid recoil, I'm curious if there are any glaring issues or if there is any kind of feedback you can give.  I'm considering buying a power supply that can produce 24v DC since the solenoid should be more powerful at that voltage, but I'm not sure if the transistor or wires will be able to handle the amps required.  The parts are pretty cheap and I have extra, so I might try it anyway.  I have played through a few games that require rapid firing and the solenoid is holding up fine under continuous use.  It isn't getting too hot or anything at 12v, so I'm not sure if the jump to 24v would cause issues with heat or not.

[mattmayhem]

Very nice write up, welcome to the board. 

I have been researching light guns for my project and found this was very helpful. I do have a question about your 2 in 1 switch. Was it necessary to add a smaller switch inside the cherry? Meaning, couldn't you have just run 2 leads off the cherry switch (one set going to your ipac/interface, and one set going to the solenoid)? I understand why you did it, but it seemed like you wanted that perfection in timing that you could have easily got from just using 1 switch. Did I miss something? Sorry if I overlooked a detail and the 2nd switch was necessary. 

[captaincatalyst]

Very nice write up, welcome to the board.  

I have been researching light guns for my project and found this was very helpful. I do have a question about your 2 in 1 switch. Was it necessary to add a smaller switch inside the cherry? Meaning, couldn't you have just run 2 leads off the cherry switch (one set going to your ipac/interface, and one set going to the solenoid)? I understand why you did it, but it seemed like you wanted that perfection in timing that you could have easily got from just using 1 switch. Did I miss something? Sorry if I overlooked a detail and the 2nd switch was necessary.  

That's a good question.  The issue is that I'm dealing with 2 parallel circuits.  If I wired the Aimtrak and the Solenoid Control board circuit into the same pole on a switch, there would likely be unwanted side-effects.  I don't want the current from one circuit touching the other.  I'm powering the solenoid circuit with a separate power supply from the PC running the Aimtrak, so they don't share a common ground either.  I'm not an EE so I can't say exactly what would happen, but I'm not going to risk damage to the Aimtrak.  There are probably better solutions like a 2-pole microswitch, but a quick Google search doesn't bring up any results for anything like that.  

Edit: This 2-pole switch might work... http://www.allelectronics.com/make-a-store/item/SMS-224/2-POLE-SNAP-ACTION-SWITCH//1.html

[mattmayhem]

I figured it was something dealing with grounds. Thanks for the info!

[TechDante]

thats awsome, can think of one gun that i need to place this into (nes zapper anyone) is it possible to see video action of these guns.

[mattmayhem]

thats awsome, can think of one gun that i need to place this into (nes zapper anyone) is it possible to see video action of these guns.

+1 for video with recoil action!

[captaincatalyst]

thats awsome, can think of one gun that i need to place this into (nes zapper anyone) is it possible to see video action of these guns.

+1 for video with recoil action!

I'll try to get a video together soon.

[TechDante]

just had a thought about the window tint, if you only need enough for the size of a 10p piece and you dont have an auto shop near by, i hit on the idea of going to an online shop that offers free samples of the stuff, then you can get the shade you need for the job.

http://www.abodewindowfilms.co.uk/acatalog/Samples.html (first site i found during search)

[captaincatalyst]

just had a thought about the window tint, if you only need enough for the size of a 10p piece and you dont have an auto shop near by, i hit on the idea of going to an online shop that offers free samples of the stuff, then you can get the shade you need for the job.

http://www.abodewindowfilms.co.uk/acatalog/Samples.html (first site i found during search)

Awesome suggestion!  That would actually be a good way to see how dark you can reasonably go at no cost.  I suggest everyone look into a free solution unless purchasing some is more convenient.

I ended up paying about $8 for a 1'x40" sheet including shipping from an eBay seller.  I'm not sure if window tinting has a standard rating scale, but mine says it is 20% dark.  The Aimtrak works fine and I can barely see through the lens to the camera behind it.  I checked the Aimtrak software and it seems to auto adjust the gain to 4 (out of 5 I believe) so you might be able to go darker.

[trevski]

Fantastic work 

I've had a couple of Happ recoil guns gathering dust while I tried to figure out how to do this very thing to them!

That's a good question.  The issue is that I'm dealing with 2 parallel circuits.  If I wired the Aimtrak and the Solenoid Control board circuit into the same pole on a switch, there would likely be unwanted side-effects.  I don't want the current from one circuit touching the other.  I'm powering the solenoid circuit with a separate power supply from the PC running the Aimtrak, so they don't share a common ground either.  I'm not an EE so I can't say exactly what would happen, but I'm not going to risk damage to the Aimtrak.  There are probably better solutions like a 2-pole microswitch, but a quick Google search doesn't bring up any results for anything like that.  

Edit: This 2-pole switch might work... http://www.allelectronics.com/make-a-store/item/SMS-224/2-POLE-SNAP-ACTION-SWITCH//1.html

Would something like this solid state relay work for this application? ebay link

Code: [Select]

DC/DC solid state relay,2A 4-60Vdc, with relay ON indicator light. Offer is for 2 off Solid State Relay.

Specifications

Contact Configuration    SPNO
Control Voltage    4 - 32Vdc
Isolation Voltage    4000Vrms
Load Voltage    4 → 60Vdc
Max On-state Voltage Drop At Rated A    1.6V
Maximum Input Current    8 mA
Maximum Load Current    2A
Maximum Load Voltage    60Vdc
Maximum Turn Off Time    1ms
Maximum Turn On Time    1ms
Minimum Load Current    0.01A
Off State Leakage Current    1.0mA
Package    Module
Surge Current Peak    8A

My thought was that you could connect this after the microswitch in series to use the 5v(?) off the aimtrack to trigger the control circuit and hook the recoil board into the other side. That way no hacking of the microswitch required.

Alternatively perhaps something on the recoil board using an Led and an opto isolator?

I'd have a stab at it but my electronics skills are limited in the extreme! 

[captaincatalyst]

Fantastic work 

I've had a couple of Happ recoil guns gathering dust while I tried to figure out how to do this very thing to them!
...
Would something like this solid state relay work for this application? ebay link

Code: [Select]

DC/DC solid state relay,2A 4-60Vdc, with relay ON indicator light. Offer is for 2 off Solid State Relay.

Specifications

Contact Configuration    SPNO
Control Voltage    4 - 32Vdc
Isolation Voltage    4000Vrms
Load Voltage    4 → 60Vdc
Max On-state Voltage Drop At Rated A    1.6V
Maximum Input Current    8 mA
Maximum Load Current    2A
Maximum Load Voltage    60Vdc
Maximum Turn Off Time    1ms
Maximum Turn On Time    1ms
Minimum Load Current    0.01A
Off State Leakage Current    1.0mA
Package    Module
Surge Current Peak    8A

My thought was that you could connect this after the microswitch in series to use the 5v(?) off the aimtrack to trigger the control circuit and hook the recoil board into the other side. That way no hacking of the microswitch required.

Alternatively perhaps something on the recoil board using an Led and an opto isolator?

I'd have a stab at it but my electronics skills are limited in the extreme! 

A solid state relay could probably do the job.  I have never worked with one so I can't say how fast they are (probably depends on the specs).  I'm not familiar with opto isolators at all.  I've ordered some 2-pole switches which I think will be the easiest, most effective solution.  These guns are still a work in progress, so there will probably be some changes from the original design. 

I also decided the 1/2" braided nylon casing is too wide.  Since USB uses 4 wires and I need 4 wires for the solenoid and recoil board, I'm experimenting with using only a CATV cable (which has 8 wires) which will bundle everything into the same cord and I can use a 1/8" or 1/4" braided nylon casing.  I've ordered different sized casings for testing.  I might very well end up with issues related to the USB wires not being shielded from the solenoid wires, but I don't think they're shielded presently and everything works fine.  I'll report with updates once I have something to report.

[drventure]

I've worked with both now, opto isolators and SSRs (to control ELWire segments).

They both seem to work equally well, though the SSRs are a little easier to wire up.

With the ELWire, I'm using them to switch AC voltage on and off very quickly to the ELWire segments, in the same way as Pulse width modulation is used to control the brightness of LED's when controlled by an LED Wiz.

That way, the LEDWiz can control ELWire segments exactly as if they were regular LEDs, complete with dimming, and pulsing special effects.

[AndyWarne]

Excellent tutorial!

I can supply Aimtrak firmware with a pulse output enabled if needed.

I would not envisage any issues with common ground especially if the 25 volts was sourced from a power adaptor as this would have a non-grounded output.

I have been researching recoil for our own guns and I am finding it really needs custom solenoids as the resistance has to be low. Running a solenoid designed for 6 volts at 24 volts is fine as long as the duty cycle is low, which in this application it would be as it is only handling short pulses.

[bkenobi]

This is an awesome project.  Nice work and excellent write up!

I would make one suggestion for people planning on following this document to make their own.  The OP's version has a very long trigger pull before the button is pressed.  I suspect that would get annoying after time since it will delay your shot due to the time it takes you to move your finger.  I would suggest doing something to make the button actuate sooner if it were my gun.  Should be fun either way though!

[captaincatalyst]

Excellent tutorial!

I can supply Aimtrak firmware with a pulse output enabled if needed.

I would not envisage any issues with common ground especially if the 25 volts was sourced from a power adaptor as this would have a non-grounded output.

I have been researching recoil for our own guns and I am finding it really needs custom solenoids as the resistance has to be low. Running a solenoid designed for 6 volts at 24 volts is fine as long as the duty cycle is low, which in this application it would be as it is only handling short pulses.

Hi Andy.  I sent you a PM.  I would love to experiment with an Aimtrak that can pulse out.  That could reduce some of the complexity in my tutorial eliminating the need to incorporate a microcontroller.  I look forward to that.

Thanks!

This is an awesome project.  Nice work and excellent write up!

I would make one suggestion for people planning on following this document to make their own.  The OP's version has a very long trigger pull before the button is pressed.  I suspect that would get annoying after time since it will delay your shot due to the time it takes you to move your finger.  I would suggest doing something to make the button actuate sooner if it were my gun.  Should be fun either way though!

Excellent suggestion.  That would be something to experiment with.  You would want to make sure the button continues to be pressed from the point the trigger makes contact all the way to the furthest in it can be pulled or you might end up with something that will push the button on the way back and push it again as it retracts resulting in 2 shots fired.  I will note that while mine does require a long trigger pull, the resistance on the trigger is not very strong, so I haven't noticed any issues with feeling it takes too long to shoot.  Ultimately it will be a matter of preference for the one creating it.

[trevski]

I can supply Aimtrak firmware with a pulse output enabled if needed.

+1 !!

[TechDante]

i am still in teh erly atages of my electronics learning curve (been experimenting with arduino) is pulse out baicaly what i am thinking it to mean that you will get a voltage pulse when a button is activated, so if the board outputs 5v this could be conected to a relay that switches to 12v of a pc psu. and you build your switch could you use a DPDT micro switch instead.

[captaincatalyst]

i am still in teh erly atages of my electronics learning curve (been experimenting with arduino) is pulse out baicaly what i am thinking it to mean that you will get a voltage pulse when a button is activated, so if the board outputs 5v this could be conected to a relay that switches to 12v of a pc psu. and you build your switch could you use a DPDT micro switch instead.

I think you've mostly got it, but if the Aimtrak could pulse out on a pin, it wouldn't necessarily, and hopefully won't, need a dedicated button to activate it.  It could take the input from the trigger switch which it uses to "click" the mouse on the computer and pulse out for the solenoid relay at the same time.  This would mean it could use a standard single pole single throw switch (i.e. the Cherry switch I was already using without modification).  Also the pulse out voltage would probably be much less than 5v, but should hopefully still be able to activate a relay, transistor, or whatever.  Oh and the Aimtrak knows when it is pointed at the screen, so it is my hope that Andy can configure the firmware with an option so that it will only pulse out when it is looking at the screen, that way for off-screen reload, it won't trigger the solenoid.  Having said that, I'm not sure what the Aimtrak is capable of, so we'll see what comes of it.

[captaincatalyst]

I notice the site I linked to for purchasing the solenoids no longer has them.  Not sure if they will re-stock.  At any rate, I remember finding one other site that had them but can't seem to find it right now.

In case you are trying to find the same kind, they are rated at 12-24v DC and about 4 ohms of resistance (give or take).  Good luck.  If I come across the other site, I will post it.

[captaincatalyst]

Found the other site with the solenoids in case anyone is interested.  I don't know anything about the site, but it's the only other place I've found these solenoids.

I'm not making much progress on my build, or the guns yet because I'm going to make things much harder on myself... My next step before continuing with my cab is to build my own CNC machine to aid in the building of my cab.  And to further complicate things, I plan to attempt to design and build my own guns with the CNC machine, so check back in a year or so and see if I've made progress or given up... 

[ErikRuud]

I have dealt with AllElectronics in the past and had no issues.

[GearHead]

If Andy can supply a pulse output all that's needed is a 1K resistor, the TIP120 transistor and a "snubber" diode in a standard relay driver circuit.



I think Andy's right and that there shouldn't be an issue with a common ground.  For those folks who aren't familiar with microcontrollers and want to build this you can substitute the microcontroller with a One Shot circuit also known as a MonoStable Multivibrator.  It's a classic 555 timer circuit that has plenty of modern low-current substitutes.  If isolation is needed you can throw in an opto coupler.

I just got my AimTrak and haven't had time to experiment with it yet.  

Andy - if you can supply me with the new firmware and let me know where I can pull the pulse output off of I can start looking at things.  FYI - the trigger switch wiring was about an inch short to mount in your gun housing.  I had to extend the wires to mount the trigger board in the right place. 

[Drakin]

Man...this is awsome...I have been puting off the 'Recoil' for the lack of trying to figure out the best way...I was going to however utilize the 555...I would be interested in the firmware also if Andy would be so kind..

captaincatalyst ..Nice Write up I like the circuit you built for the selenoid...How much is the programmer you used for the ic?

[ids]

Edit: Perhaps user error  If my understanding is now corrected, with the 555 monostable circuit, holding trigger will leave output high.  I trippled the capacitor value and noticed with a single quick triggering, the LED would stay on for approximately the length of time expected.

Great thread!

Inspired me to try this myself.  I thought I'd try the 555 monostable route to give a controlled pulse.  Google is great in this regard.  Started with http://doyle.wcdsb.ca/ICE3MI/Logic Gates/555 monostable lesson.htm


I breadboarded this, keeping it simple to begin with - just trying to drive an LED from it, using a simple switch as a trigger, and a 5V supply (DMM says 5.12V, fwiw).  Not working as expected.

So I added details from here http://www.kpsec.freeuk.com/555timer.htm#monostable  (e.g. pull-up resistor on "trigger")



When I push the switch, the LED goes on, and stays on as long as I hold the switch.  RA = 10K, C is 10uF, expecting about a 0.1s pulse.

I tried a few different 555 chips just in case - same result each time.  Verified specs of the resistors and capacitor using DMM.

Any suggestions?


Thanks