Hello all, new here but been messin about with electronics for a while. (Still don't really know anythin though ) So, I tried to build an adapter to plug my home made joystick into a snes and it hasn't worked. (The joystick itself works perfectly with other systems) I used this circuit diagram and as far as I can see I haven't bridged anything or got anything wrong but no joy. When I plug the joystick in, no controls work. I tried starting a game using another controller (streetfighter btw) and then plugging the joystick in but all that happens, is the character goes into a crouch and won't move or do anything. At one point though, it did a backflip for no reason. This is all very odd and frankly i'm extremely confused. Anyone have half a clue what would cause this behaviour?

If you could give us a picture of what you've done so far that would be helpful. I believe that circuit should work (I did something similar a while ago) so its likely a little mistake.

ok, i'll try an get a clear one. Unfortunately it's on perf strip board so it ain't gonna be too easy to see what's goin on...


Not too pretty I know, especially that shot of the back but believe it or not, I can't find any shorts....

Sorry about the longness of the replies but cos i'm new it seems that all my posts need to be checked first by a mod. Hopefully won't be too long till they decide i'm not a spam bot eh So, some explanation, there are 2 5v rails, one 2 rails above the top ic, the other in between them. The resistors are all connected to the rails and then, hopefully to the correct pins. The ground rail is the one below the bottom ic. The skinny wires go to the snes connector and the fatter ones all go do a dsub, which I plug my joystick into. Since I can't seem to find any shorts and as far as I can see, all the wires go to the correct pins, all I can think is that maybe the ics themselves are faulty? I've ordered some new ones so hopefully i'll find out soon... If anyone can see anything glaringly obvious though, please don't hesitate to tell me. Unlikely though, I know, as its pretty hard to tell what's going on in the photos.

Right, it's not the ics, just gonna have to pull it apart and try again.... Frustrating!

I have a feeling that the issue is in how you are connecting to the joystick. Mind posting pictures of those connections? Also, to test your perfboard setup, install the IC's and resistors and then just hook up the wires to the SNES connector (connecting them properly to both IC's), then you can test buttons by shorting a single resistor to ground (on the side connected to the IC pin). Each time you short, it should register a button press for the specified button. Then you can add in the wires for connecting to the joystick.

Thanks mate. I'll see what can be done. Thing is though, i'm fairly confident in my joystick connections. They all go to a dsub connector and I can't see how there are any shorts. I'd previously had a 3rd party snes pcb wired in to the dsub, which worked without problems. I was replacing it with this circuit though, because I was noticing some serious input lag, which is apparently notorious for 3rd party controllers. I'm gonna have another go I recon, probably take less time than trouble shooting but will definitely take your advice and just put in the controller wires and resistors first.

What I'm saying isn't a matter of shorts, I want to know what the internal circuitry of the joystick is and how you are interfacing it into the 4021's to know if it's even compatible with hooking up to an SNES in the way you are attempting.

Yeah, I've gone over these pictures a couple of times and I can't see anything wrong. If its not the ICs I'd think it has to be how it connects to the joystick.

The joystick is just wired as if it's part of an arcade machine. No internal circuitry etc. Grounds daisy chained together an a separate wire for each button/jostick direction all goin to different pins on a 15 pin dsub plug. I built it originally to plug into a consolized neo geo I made. Can't see any reason why it shouldn't work myself.

Have you tried testing it the way I suggested, just shorting the IC pins to ground on your protoboard? Take it one step at a time, starting with getting the controller circuit itself working, then wiring in actual buttons. That way you can isolate the issue. Also, double/triple check the 5 wires going to the SNES and make sure you didn't mix any of them up.

Just checked trying to short pins on the board to see if it'd work, but no joy. I recon there could be 2 reasons. Either there's a short that I haven't found, or it could be because of a slightly higher resistance i'm getting on the clock wire? I verified that all the wires went to the right pins and they do, but I am reading 0.9ohms resistance on that wire, where all the others have 0.3ohms. Would this make any difference? I think there might be a dirty contact in the controller port, which is only going to get worse if I don't sort it. Any ideas how i'd do this?

A difference of .6ohm isn't likely to cause issues... You do have all of your grounds connected to the brown controller wire, right? Some things to mention, pin 11 on the second IC doesn't matter, it can be GND, +5v, or disconnected entirely. Also, I don't believe you actually need separate resistors for pins 4-7 on the second IC, you should be able to use a single resistor and then tie all 4 pins together. I think you could even connect them directly to the +5v rail, just so long as those pins are all held high. But in any case, breadboards are usually a good way to go for getting all the kinks out BEFORE you solder it all together (thankfully, I see you used sockets for the IC's, so you should be able to move them without issue.

Mr. aize, unfortunately you don't state where you're from. But I can see a bag of Hula Hoops chips in the back. So that means you're from UK, right?
So it's safe to assume you got a PAL SNES console?

If you do then you should add a 10 kOhm resistor between Vcc and the clock line and another 10 kOhm resistor between Vcc and P/S.