Build Your Own Arcade Controls Forum
Main => Main Forum => Topic started by: theHotHead on November 22, 2020, 12:48:05 pm
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hi all, first post, no idea if this is the right place for it - I tried to post an albeit lengthy post in the Driving and racing section but got a message I wasn't allowed to post there - and my long post was gone :(
So I will cut to the chase, I want to build analogue pedals for use with Super Sprint and MAME, I have a Windows 10 PC and an A-Pac controller. does anyone know how to connect the POTs to the A-Pac please ? I have tried all sorts of things and at best I get it to work but intermittently.
My setup follows this:
Rudimentary foot pedal with 10K POT - cabled to a 3.5mm male audio jack (has 3 isolated connectors) - cabled to a 3.5mm female audio jack - connected to the A-Pac.
Car 1 is connected to GND/1Right/1Left
Car 2 is connected to GND/1UP/1Down
Car 3 is connected to GND/2Right/2Left
After getting in contact with Andy at Ultimarc he suggested a connection issue, so I removed my pedals and cabling from the equation and connected some spare POTs to a breadboard and then to the A-Pac. Calibrated in Windows and the POTs worked fine in Super Sprint. I did continuity tests end to end with all of my cables and connectors, everything is fine. So what am I missing ? Seems to me this is basic stuff and like I said, I have got everything working as it should, its just intermittent. Any help/advice greatly appreciated.
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I get it to work but intermittently.
Sounds like Andy's right.
Either something in your wiring is intermittent or the pots themselves are intermittent. (corrosion on the resistive element, grit causing poor connection between the wiper and resistive element, etc.)
http://wiki.arcadecontrols.com/index.php/Analog_Encoders#How_a_potentiometer_provides_the_voltage_for_an_analog_encoder_to_measure (http://wiki.arcadecontrols.com/index.php/Analog_Encoders#How_a_potentiometer_provides_the_voltage_for_an_analog_encoder_to_measure)
If you have, or can borrow, an analog multimeter for troubleshooting you will be able to see the intermittent variations via the twitching needle that a digital meter will sample, smooth, and miss.
Scott.
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Thanks for the reply Scott.
I don't have an analogue multimeter, all of the POTs I used are brand spanking new, thats not to say I might not have a bad batch. Think what I will do is bite the bullet and connect a fresh set of wires and wire them directly into some spare POTs that I will have tested prior. If they work I will use the same wires and connect to the POTs mounted on the foot pedal. If it is indeed the case that the connectors are the issue I will abandon using them - I wanted them to allow easy unplugging of the pedals when not in use. Might look into crimping some basic connectors on instead.
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Be sure the pots are already connected to the APAC before it is powered on or it will go into digital mode, as I was advised on here a while back.
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Dagnammit !! I wrote a pretty in depth reply detailing the issue and the fix and my session ended and I lost the post :angry:
So here is bitesize version:
- I wired the POTs in the same way shown on the Ultimarc website for the A-Pac (for 1Right/1Left/1Up/1Down) and it didn't work for me, the pedal action was reversed and swapping the middle and left pins made no difference
- When I wired up connecting the middle pin to ground the pedal action worked correctly, unfortunately this was the cause of the intermittent behaiour - so definitely NOT the correct way to wire the POTs
- Wiring as per the point above managed to kill 2 POTs
- Wiring the POTs in the same way shown on the Ultimarc website (for 2Right/2Left/2Up/2Down) DID work for me and, to cement the momentous victory and jubilation, connecting back my connectors also worked !!!
- When wired correctly the crosshairs move smoothly, not the juddering staccato affair I had before.
I'm chuffed to bits. Gonna be the best lockdown ever !!
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I wired the POTs in the same way shown on the Ultimarc website for the A-Pac (for 1Right/1Left/1Up/1Down) and it didn't work for me, the pedal action was reversed and swapping the middle and left pins made no difference
You might want to review that info on the wiki again.
The yellow wire on the middle tab (wiper) provides the variable voltage output that the A-Pac translates into position data.
- The wiper output goes to the A/D converter in the 1UP, 1RIGHT, 2UP, or 2RIGHT input.
If the axis is working backward, you need to swap the red and black wires on the outer tabs. (5v and ground)
- During bootup, if the A-Pac senses that a pot attached to them, it sets 1DOWN, 1LEFT, 2DOWN, and 2LEFT as 5v outputs.
- Ground is always ground.
(https://www.ultimarc.com/images/1/apac_step1.jpg)
5v and ground are the outer tabs and wiper is the middle tab.
(http://wiki.arcadecontrols.com/images/thumb/3/3e/Potentiometer_Internal_Parts.jpg/533px-Potentiometer_Internal_Parts.jpg)
Scott
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Yeah - NOW it makes sense, for the past few days though ..... :banghead:
I didn't think to swap the outer pins because one of them was GND and I thought the other 2 were the correct pins to swap :badmood:
So ultimately what I finally did was swap the outer pins and thats when everything began working properly. I think all of the hardship made for a sweeter conclusion and a bit of character building :cheers: