The first port on the Amiga is usually dedicated to a mouse, which is why a lot of the cracker-intros added to games seem to require you to click the mouse button to actually load the game. Unfortunately, this means that in order to load a two-player game you'd have to unplug the mouse and then plug in the joystick again so that player 2 has any chance of controlling anything. Restarting the computer or starting a new game means you'll have to do the two-cable merengue all over again.
The easy solution is to simply buy one of the many adapters that allows you to switch between the mouse and a joystick at the push of a button, but as I like building things I've attempted to make a new version of it - in part by just copying parts of the C64 Joystick Switcher that in many ways is very similar. I also took some inspiration from reading the december 1991 article in Elektor Magazine, available online at worldradiohistory.com.
Building the unit assumes you have at least minor experience soldering things together, recommended is at least a soldering station with adjustable temperature to get started - usually you'll want some 60/40 solder tin (if you can get that where you live). With the equipment sorted, now comes the shopping. So head on over to the BOM-section for some information on what you need, with ebay, AliExpress and similar sites you'll need to treat these as a starting search term and get what seems to match the gallery pictures.
The construction of this unit should be straight-forward, observe the direction of the diodes and solder those in - matching the stripes on the board to the ones on the diodes themselves. The do the resistors and capacitors, followed by the DIP sockets (skipping these is strictly not recommended unless you know the chips came from reliable sources).
At this point you'll need to decide if you want the mouse switcher to, well - switch automatically between the joystick and mouse or if it should remain a manual switcher. For an automated solution, you'll need to bridge both AUTO_JOY and AUTO_MOUSE - with these in place you won't need to install any of the switches (LMB and joystick fire will do the switching for you). If you want to use switches in combination with a faceplate, you'll need to use the B-variant of faceplates as those have a cutout for the switches - the switches will also need to be long enough to poke through the PCB (these are usually listed on ebay and aliexpress as 6x6x9mm momentary tactile switches - in doubt, get a kit with various lengths).
Next, solder in the IDC socket, the gap should point inwards and will match the illustration on the board itself. LEDs goes in next, these are used to indicate the currently active device - the shorter pin goes into the square hole. In order to ensure that the faceplate will fit properly, you should just tack one of the pins into place - then reheat and push it flush against the board. The male right-angle DB9 connectors should be straight-forward to install, just slot them into place and solder until satisfied that it's not going anywhere.
Insert ICs into the sockets as indicated, ensuring that the indent matches the orientation on the board - plugging them in the wrong way ensures that you'll have to order some more. Double-check before even considering plugging it into something, use the picture below as reference.
The standard A1 faceplate can be reversed to match the look you want the unit to have, at some point in the far flung future I'll hopefully have some 1bit artwork suitable to put on it. If you bought the M3 nylon hex kit as suggested, you can use four of the 8mm tall standoffs on each corner of the main PCB - fix them on the bottom using M3 nuts (snip off the remaining part of the nylon screw). Place the faceplate on top, screw it into place using - well - M3 nylon screws. Use wire cutters to cut off any metal parts protruding further down than the M3 nuts, this is just so that nothing messes up your desk surface.
I've gone into extensive detail on making up the joystick cables, so for a more detailed explanation skip on over to the C64 JoyKEY documentation to see how I did it there. Essentially you just take a 2x5 pin IDC JTAG AVR cable (common ebay listing description), find the end that fits nicely into the keying on the board and cut off the other. Take a female IDC flat cable DB9 connector, match up pin 1 with the red stripe on the cable and squeeze really hard with something to lock it into place on the cable. Wrap the cable over and push the strain relief on the connector.
There isn't many viable options for testing things out without actually plugging it into something and seeing whether the thing actually works as intended. One alternative to testing on a vintage computer is using a joystick tester, but given that those don't exactly follow a defined standard - the only one I can suggest is the Atari Joystick Tester - if it's one of those that run on a coin-cell battery, then it definitely won't work. Pushing the joystick fire button or the left mouse button will switch the active port, as long as you enabled the auto-function - if not you'll have to use the switches on the device.
When testing on the Amiga, either as the first or second step, I suggest using something like Amiga Test Kit - ensuring that the device as well as the machine itself works as intended.
The supplied KiCad files should be sufficient as both a schematic and as a starting point for ordering PCBs (basically you could just zip the contents of the export folder and upload that on a fabrication site), the schematic is also available in PDF-format and this is what you'll need to print and work your way through this things don't work as expected after assembly.
Most parts should be easy to get a hold of from your favourite local electronic component shop, but given that I don't have access to such shops where I live so everything was based on whatever I could get cheapest from eBay/AliExpress (free shipping, but plan on waiting 3-4 weeks for delivery). Values listed in parenthesis are for features that are not required for basic functionality, but you should read through the section on building the unit to ensure that you're not missing out. As always, plan on adding DIP-sockets in addition to the chips listed.
| Reference | Item | Count | Order |
|---|---|---|---|
| PCB | Fabricate using Gerber files | 1 | PCBWay |
| PCB Faceplate A1 | Fabricate using Gerber files | (1) | PCBWay |
| PCB Faceplate B1 | Fabricate using Gerber files | (1) | PCBWay |
| C1-C3 | 100nF ceramic capacitor (5mm) | 3 | |
| D1,D2 | 5mm LED | (2) | |
| D3,D4 | 1n4148 diode DO-35 | 2 | |
| J1,J2 | Female DB9 right-angle connector | 2 | |
| J3 * | 2x5 pin male IDC socket | 1 | |
| R1,R2 | 10k Ohm resistor | 2 | |
| R3,R4 | 330 Ohm resistor | (2) | |
| SW1,SW2 | 6x6x9mm momentary button | (2) | |
| U1,U2 | 74HCT4053 or CD4053 (DIP-16) | 2 | |
| U3 | NE555 (DIP-8) | 1 | |
| DB9 cable ** | Ribbon cable (9 wires), DB-9 female IDC and 2x5 pin female IDC | 1 | |
| Mounting *** | M3x8mm nylon HEX standoff | (4) | |
| Mounting *** | M3x6mm nylon hex screw | (4) | |
| Mounting *** | M3 nylon nut | (4) |
*) Can use regular double row pin headers, but it is recommended to use IDC socket as it has keying.
**) You can buy the ribbon cable, DB9 female IDC connector and 2x5 pin female IDC. The easiest however is just buying something that already has the female DB9 connector attached to a ribbon cable, then just cut off the DB9 end - finally, add the 2x5 pin female IDC connector. Pictures on my C64 JoyKEY-repository as that uses the exact same cable.
***) The easiest way of ordering these is to just one of the M3 nylon standoff kits on ebay, AliExpress or any similar sites. That way you'll get more than what you need in various sizes for future projects as well.