Making a Classic USB Amiga MousePosted: October 11, 2016
-This hack requires a dremmel with cutting and sanding attachments. Always wear goggles and ask an adult for help if your still in school. Please safety first, I take no responsibility for injury or loss of bladder control if you undertake this guide.
Not so long ago I posted an article on converting a broken Amiga Joystick into a working USB controller. In todays blog, I’m going to cover converting an old Amiga tank mouse in to a USB device. Before any of my fellow Amigans start shouting at me for desecrating a piece of retro tech, I’d like to state the mouse was pooched, the internal micro switches had clicked their last. Sure I could have repaired the switches, but I wanted an Amiga mouse for my AmigaPi and I doubt the world will miss one less yellow A500 mouse.
The first thing you’ll need is a broken mouse, please don’t bust up a working mouse, that’s just wrong and a waste of a good device. Next you’ll need to find a donor USB mouse, preferably something small, compact and simple in design. Essentially you’re looking for a budget mouse, the sort you might find in a 99p store. Below is a photo of the mouse I used, don’t worry if it has an internal LED, we can easily snip that out. Next we’ll need a beige USB cable, pick a length that suits your needs preferably something that will connect to the computer and leave enough room for the mouse to sit comfortable on your desk. If you’re still unsure, go for a 1m or 1.5m length cable as you can always trim it down to suit your needs.
We now have the essentials for making an Amiga USB mouse. Unfortunately I can’t walk you through the whole process, as it all hinges on the USB mouse you bought for the conversion. Initially you need to take both mice apart, and remove the electronics from the Amiga mouse. The only parts of the tank mouse you need are the main shell and the flexible plastic sheath around the mouse cord. The best way I’ve found to remove it, is by cutting along the under side with a sharp blade and pulling the cord out through the cut.
Let us turn our attention to the USB mouse, with the lid off you should have a good view of the PCB. The first thing you need to do is check the pinout of the cable because soon you’ll be removing it. To do this, you’ll need a multi-meter so you can perform a signal test on the each wire going from the connection point on the PCB to the pin inside the connector on the other end of the lead. I find it best to draw a simple diagram of the USB cable with the connector and the four pins laid out. I then jot down the corresponding colour wire for each pin.
Usually this is red, black, green, white, but not all cables are the same so been warned. Once you know the colours and where they go, you need to cut the cable leaving roughly 2” inches coming from the PCB as we’ll be using the remaining wires to patch in the new cable, matching red to red, black to black etc. However if you wish to you can completely remove the old cable by de-soldering it from the PCB and solder your new cable directly to the board. This makes for a neat and tidy finish, but it can prove a challenge depending on your soldering skills. So if in doubt, stick to my suggested route and leave some of the old wire in place. This way it will be easy to match up all those colour wires.
Assuming you are happy with the length of your new cable, trim back the outer sleeve and expose the four inner wires. You should have something like red, white, black and green, if your cable came from China you might find you have blue or even an orange in place of one of the standard colours. Not to worry, just check with your meter and make sure you know which pin the wire goes to. Hopefully if you’re really lucky it will match the wires on the mouse, otherwise you might end up with green as white or red as green. Again jot down the colours on your diagram, matching them up to the respective pins. Usually white and black are voltage, green and red are data. But never take anything for granted, always check!
Once you have the mouse rewired, hook it up to your computer and confirm its working. If nothing happens, check your pin out again.
The chances are your mouse came with a scroll wheel and depending on your skill level, you can either remove this with a hot air gun or use tin snips to remove the parts holding the wheel in place. Just be mindful that you don’t damage the traces on the underside of the PCB. A little wiggling is fine just try not to tear the components right off the board as that would be very bad. Assuming the scroll wheel is now removed, hook the mouse up to a computer and check that it’s still works. Hopefully it does, if not, check you haven’t broken and traces. I’ve make two Amiga mice so far and neither had an issue when the wheel was removed.
If you mouse came with a silly blue or red internal LED (note not the optical sensor!) You can snip it off, as the tank mouse doesn’t need lighting up internally. Your optic sensor does use a red led which is directed into a lens, don’t under any circumstances mess with it!
Here comes possibly the hardest part of the hack, inserting the new PCB into the tank mouse. Initially it won’t fit, for a start the optics will sit to high off the ground to be any good. So you’ll need a Dremmel to cut and sand the inside of the tank mouse, removing any lugs or protruding bits of plastic that are in the way. I’ve included a
photo to give you an idea of what it should look like, on both the mice I modded I had to superglue the cover ball cover in place. Depending on the donor mouse, the PCB might be too large for the inside of the Amiga mouse housing. If this happens you will need to trim the PCB with you Dremmel and a cutting disc. Regretfully I can’t walk you through this part as designs differ from one device to another. Usually trimming the board breaks the ground plane, you’ll need to do a little trace work with some wire to get things reconnected. Either way, you’ll have to get creative or find a friend to help you. Alternatively find yourself a donor mouse with a small PCB.
When your happy with the bottom half of the tank mouse, use a bit of blue tack and press the pcb down temporarily so that is sits inside the housing. Hook it up to your pc and take it for a test run. How does it perform? Is the cursor jumping about or shaking? If so, the optical sensor is probably sitting too high. First try pressing down the PCB with your thumb, does it improve? If it does, you might be able to get away with hot gluing the pcb while pressing it down with your thumb. Once the glue sets, the board will remain where it is. Otherwise use your dremmel to shave off a little more plastic before gluing the board in place.
Before you go gluing the board in place, we need to address the mouse buttons. You can do this one of two ways, either with a set of large micro switches or a pair of lever micro switches. The latter recreates the clicky sound of the tank mouse really well, but either will do the job just fine. Now returning to the PCB, you will need to remove the existing switches. As they will likely be too far back and not sit in the same place as the original Amiga buttons. You can either de-solder them or once again snip them off. I can’t stress the importance of being gentle at this point, if you damage the traces on the board at this stage you’ll have a hard time recovering the mess, so take it slow!
With the old switches removed, you can begin wiring in the new ones. Remember the new micro switches need to sit where the old amiga switches did inside the case. If you still have the original tank PCB, use it for comparison. If it helps, use a marker pen to drawn on the inside of the mouse case, so you have some guides to follow. Blue tack is your friend and will allow you to stick the switched down while you line them up with the mouse buttons. Once you have them lined up, you’ll need to wire them up to the new PCB. The wires will only need to be short and while it’s a little tricky to get everything sitting right, with a little time and patience it can be done, trust me I’ve done this twice.
With the new buttons wired up, you’ll need to test the mouse again by connecting it to a computer. If everything works, we’ll move on to the final stage, gluing all of the components in to place. It is up to you but I would strongly advise using a little blue tack to stick everything in place temporarily. Place the lid on the mouse and see if the mouse buttons work. Hopefully they should be clicking away inside the mouse and working just like the original. If things aren’t going exactly as planned, don’t worry because we used blue tack. Just pop open the mouse and adjust the switches a little until they are aligned with the plastic buttons build in to the upper lid. When you satisfied, remove the blue tack and use hot glue to fix everything in place. If you’ve only used a tiny bit of blue tack and don’t want to risk moving anything you can always glue the parts in place as they sit.
Finally with the buttons and PCB fixed in place, you need to put the flexible plastic piece back around the mouse cord. Simply peel it open using your thumbs and slide the cable inside. Because this collar piece is meant to keep the cable from pulling out of the mouse, you will need to use some glue to fix the cable from slipping up and down inside the collar. I did this by inserting some glue in the cut I’d made, not only does this hold the cable in place, but it also fixes the collar back together. Once the glue sets, it will stop you pulling the wires out from inside your mouse. Still, I’d recommend against holding the mouse by the cord.
All that is left to do now is to screw the mouse back together and take it for a spin. If you’ve been testing it a every step, nothing should have gone wrong. Hey presto you have a new Amiga USB mouse!