Pole Position 2 Encoder

[Brad]

I know there are loads of mouse hack posts here but I'm a bit of a tard when it comes to resistors etc so please be gentle

I've had a hacked PS1/2 wheel and pedals in this cab for a few years and it works great for 270deg games like Daytona. Unfortunately due to it being a 270deg wheel it plays like ---steaming pile of meadow muffin--- on the 360deg games like Pole Position, Sprint, Championship Sprint, Super Sprint etc and I've found that since these are the games I used to play that I'd prefer to play them instead.

Now I have the original wheel and optical encoder that went with the cab and I want to interface it to the PC running the software by either hacking a mouse or if possible using one of the minipacs I have. I just need help identifying which parts on the optical board I need to use and if possible I'd like to use the harness point. Can anyone point me in the the right direction by looking at the board photos below?

Cheers,
Brad

[huygens]

Looks like the standard four wires. The pins connected to the trace running around the outside of the board are ground.
5 volts (Vcc) goes to the other big trace (connected to the two middle pins with the solder blob).
The two finer traces coming in from the sides are your X1, X2 quadrature signals.

Your mini-pac should work fine for this. The hookup diagram from ultimarc shows the connection points for X1,X2 (spinner in the diagram), and 5volts/ground.

[Brad]

Thanks for that. I can't seem to get any life out of this optical PCB. Don't know wether I'm wiring it wrong, the PCB's dead or maybe it needs more than 5 volts? Either way thanks for the pointers =)

cheers,
Brad

[MonMotha]

Doubtful it needs more than 5V.  Try putting pull-up resistors (~4.7k to 5V) on the 2 outputs (assuming your interface board doesn't already have them).  The outputs appear to be open collector and won't create a usable signal directly into a digital input.

[Brad]

Thanks for the input. Unfortunately I know nothing about resistors etc and at this stage I'm going to investigate a mouse hack interface for it instead and see how I go =)

Cheers,
Brad

[MonMotha]

Eh, this isn't hard.  Just go to radio shack (and hope they still have parts), pick up a pack of 4.7k resistors.  Should be about a buck.  Take a resistor and connect one end to one of the signals and the other end to +5V that you're using to power the board.  Do the same for the other signal.  See what results.

[Brad]

Well I could source some from Jaycar however if you look at the PCB back I have labelled the components and the R's I'm assuming are the resistors already on there. Wouldn't that mean I don't need extra resistors?

Cheers,
Brad

[MonMotha]

These resistors would be in a different place.  It looks like the output of that board will float high-ish due to the LED that's on them, but it may not be high enough for your interface board to reliably register.  Depends on the encoder and what the value of the resistors on the board are.  Resistors are cheap, so it won't hurt anything to try.

Also, the LEDs should reflect the two outputs.  As you spin the encoder wheel between the optical pickups, you should be able to see the LEDs flash on and off.  If you spin it slowly and watch carefully, you should see that outputs are in quadrature (see the graph at the right).  You can use these LEDs to visually confirm that everything is working prior to your interface board.