Where to get the ground from a mouse hack

[goofy]

Stupid question here, but how do I determine where the ground is on a mouse hack.

I've taken apart my mouse, I've got all of the components identified (the X/Y transmitters, +5V power), but I don't know where the ground is.

This is going to attach to my 3" Happ trackball.

Any help would be great. By the way, I don't want to get the power from the computer or elsewhere, I'd prefer to do it all from the mouse.

[Bgnome]

it would help if you posted a pic..
but basically, the ground trace should be the thickest one, connect a whole bunch of components including the switches and ir stuff, and usually is continuous with a black wire on the main connector.

[goofy]

Here's a picture. Thanks for the help.

[goofy]

Here's one that's closer up:

[Bgnome]

this is my best guess on a ground trace.  i figure that since its the one that connects all the buttons and some other stuff it is pretty likely.  the thickness o f the trace doesnt really help though.  i dont know what the other side of the board looks like but i am guessing that those 2 solder points are continuous through the area ive indicated with the purple fuzzy spot.  but once again, it is just a guess so i would check for continuity through everything when following the trace.  is that last wire black?

a couple other things i have noticed:
you are kind of cooking off those solder pads so you might want to consider getting a lower wattage iron or not hold it there as long.
you are also using solid copper.  this isnt all that great for arcade setups due to its lack of flexibility and i dont think it lends itself well to crimping quick disconnects to.

[SirPoonga]

How do you plan on using this?  How does it connect to your computer?  I don't see a USB or ps/2 cord at all.  I'd just hook up to the ground wire from that. Same with 5v.

[SirPeale]

Was just noticing the lack of of either PS/2 or USB cable.  Getting it from PS/2 is easy, that's what I did for my hack.  

[goofy]

Here's a pic of the other side of the board.

Wow, thanks for all of the great information and quick responses. I do in fact have a ps/2 cord, it is just disconnected from the PCB for now. I never even thought to use that for the power and ground. The PS/2 connectors are the five horizontal solder points toward the upper left corner of the first two pictures. The ground is the far left and the power is the far right of those 5!

As for my wires, I have discovered the hard way that they are not that good to work with. Thanks for the tip however. I am going to get some new wire in the coming days.

My projects so far have been mostly for learning purposes, so the wire I have now has been serving its purpose--but it really is a pain to work with.

As for melting the solder points, I thought that happened because I was just no good at desoldering. But, maybe it is because my iron is too hot (probably both). My iron is just a cheapo from Radio Shack and is marked as 23W. I'm also just using a little desoldering bulb to suck up the solder after heating it (looks something like the little suction bulbs for cleaning babies noses).

This mouse hack is going to connect to a Happ Trackball. I may also use it to try to build a spinner as well.

Again, thanks for all the help. You guys are great!

[goofy]

One last question/confirmation. The black wire from the PCB goes to the far left (on the first two pictures) solder point of the 5 horizontal points in the upper left hand corner of the board. Is this the ground, like I originally thought. This only connects to two points so I am still a bit confused.

[Bgnome]

the signs i have mentioned are common trends but certainly not the rule..

to be absolutely sure, you can plug the cable in to the computer and measure the voltage across the red and the black wire.  it will be 5v when the black probe is on the ground, which is almost always the black wire, and the red probe on the power, usually red also..

[goofy]

The lead that you've identified to the far right of the 5 horizontal points (which is the one four points over to the right from the one that I marked) traces over to the center pin of the 3-legged transmitter node that I removed.

Now, from everything that I've read, that center node is the power lead, correct?

Unfortunately, I don't have a volt meter to test this with.

[SirPeale]

Using the diagram here: http://www.networktechinc.com/technote.html

Find which pin is the ground pine.  Get your multimeter, and figure which wire corresponds to that pin.  Don't rely on wire color, that can be a costly mistake.

What I did was to unsolder the wire alltogether from the hole, wrap the two ends together, and solder it back into the hole.

[krick]

As for melting the solder points, I thought that happened because I was just no good at desoldering. But, maybe it is because my iron is too hot (probably both). My iron is just a cheapo from Radio Shack and is marked as 23W. I'm also just using a little desoldering bulb to suck up the solder after heating it (looks something like the little suction bulbs for cleaning babies noses).

You should pick up a "solder sucker" from Radio $hack they help a lot with desoldering...
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=64-2098
Spring loaded makes for easy one-handed operation.

It's also handy to have some clip on heatsinks to prevent you from melting wire and other components...
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=276-1567
Helps stop wire insulation from melting from the heat.

As far as the iron wattage goes...
Everybody says to use a 15 watt iron.  I have two 15 watt irons and I always end up going back to my trusty old 30 watt iron (a piece of crap 15+ year old unit from Radio $hack)

With 30 watts, you have to be careful that you don't hold it on too long but if you prepare properly, you won't have to.

I'm not a soldering expert by any means but here's some tips that I find useful:

• MOST IMPORTANT: make sure that your iron's tip is properly cleaned and tinned with solder.
• Use good solder.  I use .032dia 60/40 rosin core and I have good luck with it.
• If you can, it sometimes helps to pre-tin your wire ends before putting them through the holes.
• Keep an old wet washcloth or wet sponge handy and wipe the iron tip often.
• De-soldering is easiest if you add extra solder to the joint first, then heat it up and suck it away with the solder sucker.  It's all a matter of giving the sucker something to "grab" onto.
• I sometimes "cheat" by touching the solder to the iron first to make a little "bubble" of solder on the tip just before touching it to the component I'm trying to solder.  I find that this often "primes the pump" so-to-speak and allows the heat to transfer much more quickly, shortening the solder time.

[goofy]

OK, another question here. I've traced the leads and the point labeled 5 in the diagram above traces out to the +5V power according to the PS/2 Pinout diagrams at (http://www.bbdsoft.com/keyboard.html) and (http://www.networktechinc.com/technote.html). This is as I expected so it was nice to be confirmed.

Now, the point labeled 4 traces out to the GND from those diagrams. However, the point labeled 1 traces out to the ring around the 6 pins in the ps/2 connector (the part that plugs into the computer, well the ring that circles those 6 pins). Wouldn't that be the ground? However, according to the pinout diagrams in the above mentioned websites, the point labeled 4 in my diagram should be the ground. Does this seem correct?

Thanks for all the help, I really appreciate it. I just want to make sure I'm doing this all correctly.

Also, thanks for the soldering suggestions, those will really help.

Cheers.

[Bgnome]

i am not an electrician so take this info with a pinch of salt.  my understanding is that they are both grounds, but not continuous.  the ring/shell of the connector is earth/ground whearas pin 4, as you have labelled it, is the circuit ground.  like in the situation where trackballs sometimes have a green grounding wire sticking out of them which is meant for an earth/ground, they still have a separate ground wire meant for the optics.  bottom line, use pin 4.

[goofy]

OK, thank you very much for the information; I really appreciate all the help you've given me.

I'll let you know if I get it working and how it does.

Cheers.

[goofy]

Well, I got it hooked up tonight and working. Now, I just need to fiddle with the settings, hook up the buttons and mount it into something. But, it works.

Thanks so much, couldn't have done it without all the help here.