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Author Topic: Actuator Project ( Was MRotate4)  (Read 9220 times)

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DaOld Man

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Actuator Project ( Was MRotate4)
« on: April 07, 2012, 10:17:11 pm »
***************************************************************
5/13/2012: I changed the name of this thread because I will soon release MRotate4, and I plan to make a new thread detailing what MRotate4 is then.
I sort of  steered this thread towards actuators, which is ok. But the name was misleading, since it really isnt about MRotate4.
Nothing else in this thread has been changed, and the remainder is the original.
***************************************************************


Ok, I have been working on a rig to rotate a LCD monitor using one of DarthPauls actuators. (Thanks DarthPaul!).
The initial test was a complete success.
I am also working on a new version of MRotate that I  plan to use on this rig.
This version will use the 9 pin (or 25 pin if you have a really old computer) com port.
I am calling this version MRotate4.
It will not require any kind of pic chip to get I/O. It will use two pins for outputs to turn on the drive, and two pins for inputs to monitor the limit switches.
The pins are: (on a 9 pin port)
Outputs:
Pin 4 DTR
Pin 7 RTS
Inputs:
Pin 1 DCD
Pin 6 DSR

The comport wont require the special inpout32.dll that the printer port needs, and it shouldnt have the annoying "some pins turn on during boot up".
Im not sure if a usb to serial convertor will work, but Im guessing it will.

I plan to make the drive for the motor very simple too.

The disadvantages of using the comport (without some sort of I/O chip), is the limited number of outputs and inputs.
So some of the features available in other versions wont be available in MRotate4. (Degauss, monitor off, drive enable, stop button, etc)

My question is: How many of you have comports on your mame PC? I know the comport is going the same path as the printer port, but I have seen some fairly new computers with at least one comport.

I have attached a picture of my test rig. It is strapped to a bar stool right now, notice the belt? (I have often wondered why God allowed me to get fat in my old years, now I know why LOL).
I used the same pine 2X4 rig I built for the stepper motor trial, which was a failure. The actuator, however works very well.



« Last Edit: May 13, 2012, 10:51:24 am by DaOld Man »

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Re: MRotate4
« Reply #1 on: April 07, 2012, 10:57:21 pm »
Here is a better picture of the rig. I added some labels to help explain what I am doing.

Le Chuck

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Re: MRotate4
« Reply #2 on: April 07, 2012, 11:38:13 pm »
All my laptops and netbooks have comports, and all my cabs above the micro scale have them as well.  I'd be interested the USB route though since I don't know how long the com port is going to hold on. 

Working on your 2012 UCA Software acceptance speech yet?  Have you even written your 2011 acceptance speech? 

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Re: MRotate4
« Reply #3 on: April 08, 2012, 08:21:53 am »
All my laptops and netbooks have comports, and all my cabs above the micro scale have them as well.  I'd be interested the USB route though since I don't know how long the com port is going to hold on. 

Working on your 2012 UCA Software acceptance speech yet?  Have you even written your 2011 acceptance speech? 

Well, I still have the MRotate USB version on the back burner. Its just that I want to build a way to make the monitor turn without being too complicated and not very expensive. (I know, just look at one of my schematics and laugh about my "complicated" statement!)

About the award, I want to thank you for your work LeChuck, and I really do appreciate it, but I was thinking, what does everyone think about whoever wins this year take a break the next year and not be eligible? This way others would have a shot, although Im not saying I have a shot next year, it's just that I dont think any of us would feel right winning two years in a row.  I will gladly go along with whatever the community wants to do. There are many very talented people (myself excluded) on here that could easily walk away with the award every year if they just put a little extra effort in it. Just trying to be fair and share the wealth.
This is probably a topic best for your thread over in the Main Forum.

Le Chuck

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Re: MRotate4
« Reply #4 on: April 08, 2012, 09:36:17 am »
I'm working on a low cost simple solution myself via USB but it's reliant on a very lite monitor.  If you can get something that is near idiot proof but has the ass to move larger loads I'm all for that.  Eitherway you're a pioneer man, if there's a need I'm sure you'll come up with a good solution.

As for the UCA, that's a valid recommendation.  I would probably tweek it to allow them to be nominated and confirmed but are excluded from the final voting.  Kinda like Miss America passing the crown.  During her reign Miss America visited XYZ and took part in these charities and build another sweet cab. 

We'll table all that for now tho, it's too soon to get back in the weeds on the UCAs for me but I think you can exepect to see a thread in Dec/Jan timeframe looking to discuss ways to make the UCAs better and create more involvement.   

DaOld Man

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Re: MRotate4
« Reply #5 on: April 09, 2012, 12:19:20 pm »
I have been following your project LeChuck, and it is looking good.

I posted a youtube video of the actuator rig in action. Please excuse the quality of the video, it and the background both suck, but it is my first attempt, so hopefully I will make a better one soon.

rotatevideo 002.MOV

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Re: MRotate4
« Reply #6 on: April 09, 2012, 02:30:42 pm »
That's a really smooth transisiton.  Anxious to see more, keep them coming. 

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Re: MRotate4
« Reply #7 on: April 09, 2012, 02:36:54 pm »
Man, worm drive ftw!.  I wonder how small they make those.  seems bulletproof for a rotating restrictor job. 


If I could just fit that garbage can in my cab!

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Re: MRotate4
« Reply #8 on: April 10, 2012, 01:28:42 am »
TJC, I was thinking about putting that garbage can on ebay, but if you want it I can make you a special price, but the garbage is going to be extra.  ;D
Also, I have been thinking about how to implement something of this nature on a 4-8 joystick, but the servos seem to work real good.

Ok, Ive got a couple of fairly decent (better) videos, shot from the other side of the rig.

rotatevideo 005.MOV



rotatevideo 006.MOV


darthpaul

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Re: MRotate4
« Reply #9 on: April 11, 2012, 07:24:13 pm »
 :applaud: :applaud: :notworthy: Now if we can only get it to work on a big old CRT.
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Re: MRotate4
« Reply #10 on: April 12, 2012, 03:01:07 am »
Yes that might be a challenge, but I think it could be done.
Any ideas?

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Re: MRotate4
« Reply #11 on: April 12, 2012, 06:55:16 pm »
This is something I would use if I get the OK to build a cabinet for work and I would be using a CRT monitor because it's free, what are your plans for the motor drive?
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Re: MRotate4
« Reply #12 on: April 13, 2012, 02:03:49 am »
This is something I would use if I get the OK to build a cabinet for work and I would be using a CRT monitor because it's free, what are your plans for the motor drive?

Im glad you asked about the motor drive. I plan to build one using two relays, two NPN transistors, and a few diodes and resistors. Will be controlled via serial (com) port.
I got in from work tonight (working afternoon shift this week), and some parts I ordered for the drive were in the mailbox!
I ordered them from allelectronics.com, shipping is high (7 bucks for the parts a I ordered), but they got here super quick.
Here are the parts. I ordered 2 extra relays and a whole bunch of 1 amp 400 V diodes (my junk box was running low.)
Also got some extra transistors. Although not a real necessity, you gotta love the terminal strips.

So now I need to breadboard it and make sure it will work, then it's off to Radio Shack to pick up one of those neat little copper clad pre-drilled PC boards.
More pics and schematics to come.

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Re: MRotate4
« Reply #13 on: April 14, 2012, 12:38:32 am »
Will MRotate4 only work with your motor driver or will it also work with a more conventional Pololu drive like the one I'm currently using with Mrotate and CPRotate?
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Re: MRotate4
« Reply #14 on: April 14, 2012, 11:04:20 am »
Mrotate4 will control the serial port, so it is very possible to use the serial port to control your drive if it is currently being controlled by the printer port.
The big difference between using MRotate3 with the printer port and MRotate4 with the serial port is the limited number of available inputs and outputs with Mrotate4.
Printer port has 8 outputs and 5 inputs that are very easy to interface with.
The serial port, in the way MRotate4 will access it, has only 2 outputs and 2 inputs.
So, if your drive only needs two signals to run (forward and reverse) and you only need two signals back to the PC (limit switches), then this new setup will do nicely.
I do plan to incorporate optional speed control, dynamic braking and sounds in MRotate4.
But monitor on/off control, degaussing, parking brake control, optional stop input and parking brake released input will not be available in MRotate4, simply due to unavailable inputs and outputs.
Since you already have your rig set up with the printer port, i suggest you do not go the route of the serial port.
I am creating MRotate4 for simplicity, to encourage others to get on the rotating bandwagon.

When I am finished with this project I plan (no, I promise) to pick up the MRotateUSB project again (May be renamed MRotate5) .
Now this will open up the USB port for a combination of 16 points of access (8 outs 8 ins, 5 outs 11 ins, etc)
It will just not be as simple or cheap to implement as its predecessors.

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Re: MRotate4
« Reply #15 on: April 14, 2012, 04:58:01 pm »
I would plan on using this on the cabinet I am hoping I get the go a head to do for my job. I don't think I would need any of the extra features that Mrotate3S has, I'm not using them now.
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Re: MRotate4
« Reply #16 on: April 14, 2012, 05:31:32 pm »
I would plan on using this on the cabinet I am hoping I get the go a head to do for my job. I don't think I would need any of the extra features that Mrotate3S has, I'm not using them now.

Cool. I am just about finished with the drive.
Are you going to try to use the actuator to turn the monitor?

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Re: MRotate4
« Reply #17 on: April 14, 2012, 06:40:11 pm »
No, I have to go with the tried and true friction drive to turn that beast.
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Re: MRotate4
« Reply #18 on: April 15, 2012, 10:07:12 pm »
Alright, a little progress to report:
I got the relay drive built and it works like a charm!
The drilled PC board I got from Radio Shack was a little hard to use with the relays I bought. The relay pins did not line up exactly with the holes in the board. I had to bend the pins a little, and the relays are slightly "cock-eyed", but it works good.
Here are a couple of pics.
First is the relay with the 9 pin comport connector laying beside it.
Second pic has a arcade pushbutton laying beside it for size comparison.
I will try to get together a parts list and cost, also a schematic diagram of this drive.
I think this will be a simple and cheap way to go if your rotating rig does not need speed control.
MRotate4 to be released very soon.

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Re: MRotate4
« Reply #19 on: April 15, 2012, 10:21:43 pm »
And here is a quick and dirty hookup diagram.

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Re: MRotate4
« Reply #20 on: April 25, 2012, 11:08:34 am »
Here is a diagram of the relay and transistor I used for this project:

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Re: MRotate4
« Reply #21 on: April 25, 2012, 11:11:09 am »
Your documentation is awesome as usual.  Keep it up!

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Re: MRotate4
« Reply #22 on: April 25, 2012, 12:16:01 pm »
Thanks LeChuck, I hope it is useful.

Here is the schematic diagram of my simple drive. (Any suggestions for a name for this drive? (be nice!)).
I found that it is not necessary to use both contacts on the limit switches. I just wired both the terminals on the strip for each switch to just the NC contact of the switch. So I adjusted this drawing to show that, no need to use extra terminals if you dont need them.

Edit: I left out one very important thing on this drawing, and that is a fuse on the power from the power supply.
The fuse can be an auto type fuse, and it should be rated in amps high enough to not blow during normal operation, but low enough to blow if the motor hangs up. With the actuator Im using, I found that while the motor is running it draws around a half amp, and when it stalls it draws right at 5 amps.
Why would it stall? If something happened to a limit switch and the circuit wasnt turned off when it should be, the actuator would travel until it hit a mechanical stop. This is when the motor would stall, or cant turn. Current jumps high during this time and if power isnt removed pretty quick, the motor will get hot, possible damaging the motor or the power supply. So this is where the fuse comes into play. The fuse blows (or opens up), turning off power to the circuit and the motor.
I feel this is very important. Im thinking about trying a 1.5 amp fuse on this circuit. If it blows too soon, I will up the amps by .5. (The fuse must be large enough to handle the startup current of the motor, which can be much higher than the running current for a split second).
The power supply must also be rated to supply enough current to blow the fuse, should the motor stall.
Say for instance I use a power supply rated for 1 amp, it would probably be enough to run the motor normally, but If I use a 2 amp fuse and the motor stalls, the power supply may not be able to pump 2 amps into the circuit long enough for the fuse to blow quickly. This could damage the power supply.
A good test would be to move the limit switch out of the way and let the motor stall while supervising it. Fuse should blow before anything heats up. And by supervising, I mean hand on the power cord, ready to pull the power.
« Last Edit: April 25, 2012, 12:47:17 pm by DaOld Man »

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Re: MRotate4
« Reply #23 on: April 25, 2012, 01:30:16 pm »
Ok, so maybe you dont want to use relays, cause let's face it relays are old school, and they are mechanical, which means eventually they will wear out and fail, even though it may be many many years down the road, there is a point which they will give up the ghost.
But in defense of relays, they are much simpler and much more forgivable about current surges and short circuits than solid state devices are.
One big disadvantage for some folks would be that you cannot control the speed of the motor by pulsing the relays on and off, like you can with a solid state device. (Such as a transistor).
So you are planning on using a solid state drive AKA as "H Drive", but you like the idea of using the comport to control it?
Well here is a circuit that basically cuts out the relays and two of the diodes of the previous circuit, but adds two resistors, to offer an interface between the comport and the H Drive.
I plan to offer PWM speed control in MRotate4 as an option. (Cant use it on the relay drive though).
I havent tested this circuit, but I am pretty sure it will work, but as with all of the circuits and software I offer, use at your own risk.
Connecting anything to your computer can be a risky thing. You can fry your computer if not wired properly.
I have tested the relay drive on my main desktop PC with no problems at all, but keep in mind you are doing this at your own risk.


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Re: MRotate4
« Reply #24 on: April 25, 2012, 01:41:48 pm »
This might be a better circuit for the H drive. Notice that in this circuit, when a limit switch opens, the input on the H drive will turn off immediately, and not rely on the software turning it off.
Let me add also the same speech I made above about the fuse.

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Re: MRotate4
« Reply #25 on: April 25, 2012, 02:13:10 pm »
This is some great stuff man, nothing that is going to knock socks off immediately but it's exactly the stuff that makes some cockamamey ideal possible. 

As for adding the fuse that is a really great solution.  I ran into the same thing on my controller rotate with the servo hanging.  I really fought with how to get it around it.  The issue was that the servo was trying to push past the stop and wouldn't shut down at the right marker.  Due to scale rather than try to fix with switches I just used a script to shut it down after one second (the process takes .5 second).  It isn't a failsafe like the fuse tho, which really protects the system from unforeseeable failures.  When I upscale I'll be hitting this thread up first. 

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Re: MRotate4 (Update 4/30/12)
« Reply #26 on: April 30, 2012, 04:11:58 pm »
Ok, I found a limit switch arm that I figured would work and look better than the hastily thrown together crank I used to test the actuator rig.
I had to drill the hole in the center of the arm to fit the 3/8" shaft.
The arm had a roller on the end, I removed it and bored that hole out to 1/4"
It is adjustable in crank length and rotation angle on shaft.
I am happy with the way it turned out:



Next I made bearings for the actuator pivot points.
I used brass pipe plugs (3/8"). I drill out a hole in the center for the pivot. (1/4", a little big but as close to pivot diameter that I had). I then filled the plug with wood putty. The putty set up pretty hard. I did this to keep oil from soaking into the wood and to help steady the pivot. Probably  not necessary. Then I drilled out the wood putty (1/4") to the depth of the length of the pivot.
I then bored 1/2" holes in the wood supports and threaded the plugs in. It is a tight fit and I dont think they are going anywhere.
The actuator pivots a lot smoother and stays in line better.
Here is a pic of the backside of the bushing, showing the wood putty filler.



First pic of the new crank was with the monitor in vertical position. here it is in horizontal. (I dont have the mechanical stops or limit switches installed yet, its a bit past horizontal. You can see where I marked the stop for vertical (probably use a 1/4" bolt through the 2X4). There is a hole where I mounted the servo once upon a time. I plan to use this for the horizontal stop bolt.
I make the mechanical stops so the monitor can turn past the level vert and horz positions. This allows me some adjustment room on the switches, and if it hits the mechanical stop I will know because the screen will be crooked.



I then set up the rig to test for proper alignment. I ran small wirewrapping wire between the corners to find center of the screen. I then set up my camera tripod with a wood skewer for a pointer.
This pic shows monitor in vertical and pointer lined up on screen center.



And here it is rotated to horizontal. The screen is about 1/4" off center from vertical position.
Im going to have to live with this. I plan to center the monitor with the cabinet while in horizontal position, so maybe 1/4" to the side while in vertical wont be too noticeable.



And here is how I set up the centering guide. I ran the small wires (can be thread too) between each corner of the screen (not the monitor but the viewable portion of the screen). I scotch taped the wires to the monitor to hold in place. Where the wires intersect should be the center of the screen.



Next on my agenda for this project: Mount mechanical stops and rig up limit switches.

« Last Edit: April 30, 2012, 04:14:02 pm by DaOld Man »

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Re: MRotate4 (Update 4/30/12)
« Reply #27 on: May 01, 2012, 11:27:31 am »
Definitely "borrowing" that adjustable arm idea.  :)

I know I'm not going to be able to get the screen exactly centered with my tools and ability.
My plan is to have a round logo displayed while rotating, and adjust the position of that until the picture is centered.
That will at least create an illusion of the screen being perfectly centered.

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Re: MRotate4 (Update 4/30/12)
« Reply #28 on: May 01, 2012, 01:43:46 pm »
I have been experimenting with the adjustable arm.
I have found that the monitor turns faster on a short radius (arm adjusted towards center), but it is a lot "jerkier" so faster may not be better.
I am also experimenting with sliding a spacer over the worm shaft, which makes a very good mechanical stop for actuator retracting.
This actuator is so strong that it tries to bend the crank arm, so a extended mechanical stop will have to stop the end of the actuator screw, not the crank arm.
There is another hole in the actuator screw shaft on the opposite end, I thought about using that to make a mechanical stop for extended. But with the setup I posted, the hole in the screw end disappears into the actuator when extended, thats why I messed around with the crank radius adjustment, I did get the hole in the screw to still appear when monitor is just slightly past vertical. I put a finishing nail in the hole and extended the screw shaft. It bent the nail when it reached it, but it did stop the motor. I may have to move the actuator closer to the crank to get what I need. A nail is not going to work either. Like I said this actuator is pretty strong.
I like the way the monitor turns with the crank radius as in the pics I last posted. Much smoother. Will try to stay away from a short radius on the crank.

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Re: MRotate4 (Update 4/30/12)
« Reply #29 on: May 01, 2012, 03:21:13 pm »
I have been experimenting with the adjustable arm.
I have found that the monitor turns faster on a short radius (arm adjusted towards center), but it is a lot "jerkier" so faster may not be better.
I am also experimenting with sliding a spacer over the worm shaft, which makes a very good mechanical stop for actuator retracting.
This actuator is so strong that it tries to bend the crank arm, so a extended mechanical stop will have to stop the end of the actuator screw, not the crank arm.
There is another hole in the actuator screw shaft on the opposite end, I thought about using that to make a mechanical stop for extended. But with the setup I posted, the hole in the screw end disappears into the actuator when extended, thats why I messed around with the crank radius adjustment, I did get the hole in the screw to still appear when monitor is just slightly past vertical. I put a finishing nail in the hole and extended the screw shaft. It bent the nail when it reached it, but it did stop the motor. I may have to move the actuator closer to the crank to get what I need. A nail is not going to work either. Like I said this actuator is pretty strong.
I like the way the monitor turns with the crank radius as in the pics I last posted. Much smoother. Will try to stay away from a short radius on the crank.


I've been planning on using the crank length to adjust the speed.  I picture a square on the back of the monitor and I need to move one corner to the position of the next corner to get 90 degrees rotation.  My actuator is lighter duty and rated at 1.5"/second, so I'd need a 4.5" square if I wanted the rotation to be 3 seconds.  (slightly longer since the actuator isn't travelling a straight line, but close enough)  ......at least in theory. 

I'm waiting on a few more parts in the mail before testing.  I thought about trying to get the length perfect so that it would hit the built in limit switches each way, but I'm not sure I'd be happy waiting that long for the monitor to turn.  If I do go this route, can mrotate work without any input from limit switches?

BTW, I ordered the $7 motor driver from India that you linked to in another thread.
http://robokitsworld.com/index.php?main_page=product_info&cPath=73&products_id=15
Partially trackable and uninsured shipping, 7-15 day delivery was under $10.

DaOld Man

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Re: MRotate4 (Update 4/30/12)
« Reply #30 on: May 01, 2012, 03:52:32 pm »
....can mrotate work without any input from limit switches?

BTW, I ordered the $7 motor driver from India that you linked to in another thread.


Mrotate can do it without limit switches, just set the time limits and turn off the pop up message option. MRotate4 will be able to do the same, if you are planning on going with the serial port.

I have not tried that driver, I have so far built my own, but it looks like a real good price, let me know how you like it.

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Re: MRotate4 (Update 4/30/12)
« Reply #31 on: May 01, 2012, 03:58:59 pm »
I plan to use the parallel port version.  (even though I'm posting in the mrotate4 thread :-[  )

Continuing off topic discussion:

I've been planning on using the crank length to adjust the speed.  I picture a square on the back of the monitor and I need to move one corner to the position of the next corner to get 90 degrees rotation.  My actuator is lighter duty and rated at 1.5"/second, so I'd need a 4.5" square if I wanted the rotation to be 3 seconds.  (slightly longer since the actuator isn't travelling a straight line, but close enough)  ......at least in theory.  

To expand on this.... to get the length of the crank needed, you'd use the Pythagorean Theorem.

where both a and b are the sides of your square (the distance between the starting and stopping point of your actuator) and the midpoint of c is the center.
So half of c is the length of crank needed.
Using my 4.5" square as an example (both a and b=4.5)
 and popping it into an online calcuator:
http://www.basic-mathematics.com/pythagorean-theorem-calculator.html
c is 6.36.  
So my crank would need to measure 3.18" from the center of both pivot points to get the result I want.

To use the full 6" stroke of the actuator, I'd need a 4.25" crank.

DaOld Man, don't be afraid to tell me to get off of your lawn!  ;)
« Last Edit: May 01, 2012, 08:32:20 pm by BadMouth »

ataruzzolo

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Re: MRotate4 (Update 4/30/12)
« Reply #32 on: May 01, 2012, 04:50:50 pm »
I used Pythagorean Theorem myself this morning to find the lenght of the crank!
I'm doing a little alteration (again) to my rotating setup and a little actuator is coming in use.
First edition was the classical friction solution, one month after I remaked the mechanism and the motion was transmitted by gear, now is time for the linear actuator...

I'll post some photo...

DaOld Man

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Re: MRotate4 (Update 4/30/12)
« Reply #33 on: May 01, 2012, 11:18:42 pm »
I plan to use the parallel port version.  (even though I'm posting in the mrotate4 thread :-[  )

Continuing off topic discussion:

I've been planning on using the crank length to adjust the speed.  I picture a square on the back of the monitor and I need to move one corner to the position of the next corner to get 90 degrees rotation.  My actuator is lighter duty and rated at 1.5"/second, so I'd need a 4.5" square if I wanted the rotation to be 3 seconds.  (slightly longer since the actuator isn't travelling a straight line, but close enough)  ......at least in theory.  

To expand on this.... to get the length of the crank needed, you'd use the Pythagorean Theorem.

where both a and b are the sides of your square (the distance between the starting and stopping point of your actuator) and the midpoint of c is the center.
So half of c is the length of crank needed.
Using my 4.5" square as an example (both a and b=4.5)
 and popping it into an online calcuator:
http://www.basic-mathematics.com/pythagorean-theorem-calculator.html
c is 6.36.  
So my crank would need to measure 3.18" from the center of both pivot points to get the result I want.

To use the full 6" stroke of the actuator, I'd need a 4.25" crank.

DaOld Man, don't be afraid to tell me to get off of your lawn!  ;)

Cool, thanks for the theorem.. The stroke of the actuator Im using is approx 4.5".
I went to the hardware store today and I couldnt find anything to use for a stop. I did find some pins that fir pretty snug in the hole on the end of the threaded screw, so I think I will use that for the horizontal (retracted) mechanical stop.
Now I got to figure out how to mount the limit switches, I want to be able to adjust the position of them or the striker to get monitor dead on horizontal and vertical.
I like your actuator with the built in switches, thats going to make it a lot easier.
I though about building a small circuit that monitors the current on the motor, then use the mechanical stops to stop the monitor in correct positions. When the circuit senses the current going up, it will signal the drive to turn off. But I dont think I like the idea of straining the motor every time it moves. Sooner or later something will give.
I will get some more pics soon, looking forward to seeing your project in action.
And go ahead and walk across the lawn, just step around the crab grass. LOL
« Last Edit: May 01, 2012, 11:28:32 pm by DaOld Man »

DaOld Man

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Re: MRotate4 (Update 4/30/12)
« Reply #34 on: May 01, 2012, 11:30:48 pm »
I used Pythagorean Theorem myself this morning to find the lenght of the crank!
I'm doing a little alteration (again) to my rotating setup and a little actuator is coming in use.
First edition was the classical friction solution, one month after I remaked the mechanism and the motion was transmitted by gear, now is time for the linear actuator...

I'll post some photo...


Alright, looks like the actuator idea is catching on! Looking forward to seeing your progress.
I wonder if these actuators would turn a CRT? I am thinking if it has the correct bearings the one i have would.

ataruzzolo

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Re: MRotate4 (Update 4/30/12)
« Reply #35 on: May 02, 2012, 04:27:15 pm »
This is my home made LEGO linear actuator. Actually it consists of two LEGO linear actuators (part number 61927c01), a XL LEGO Motor (part number 8882), some spare lego bricks/gears and a ball bearing drawer slides (it comes from  Samsung monitor pivottable stand I placed in the cab) to strengthen the whole.


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Re: MRotate4 (Update 4/30/12)
« Reply #36 on: May 02, 2012, 04:34:04 pm »
^ I'll be damned.  That's pretty impressive.  Video?

DaOld Man

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Re: MRotate4 (Update 4/30/12)
« Reply #37 on: May 02, 2012, 05:09:46 pm »
I agree. Very impressive. Why did you use two actuators?

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Re: MRotate4 (Update 4/30/12)
« Reply #38 on: May 02, 2012, 05:19:42 pm »
Thanks ;)
I believe my crappy camera can't record video, tomorrow (I need some daylight!) I will try with the phone.


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Re: MRotate4 (Update 4/30/12)
« Reply #39 on: May 02, 2012, 05:20:44 pm »
Ok, I have the mechanical stop problem fixed.

First I moved the actuator supports 1/2" closer to the crank.
I then readjusted the crank to get the clevis block to bottom out against the actuator body when it goes past horizontal. Here you can see the clevis bottomed out:



And here is a pic of the monitor position at this point:



And I inserted a pin in the other end of the screw, I couldnt insert it too far because of small clearance between the screw and the motor housing. Pic is a little blurred so I drew a red circle around the pin:




And here it is at the mechanical stop for vertical:



And finally, the position of the monitor at the vertical mechanical stop:



Now that I have the mechanical stops figured out, need to work on limit switches now.

  
 

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