potentiometer trigger

kurtworxxx

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May 2, 2025
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I found my old micro Scalextric track stored away in our old house and I thought I could do some tinkering to make it work, maybe give it to my nephews. The plan is to build a PWM speed controller using a potentiometer shaped like a trigger. Anyone here have a clue where to find one that's budget-friendly? I mean, if it's breaking the bank then might as well get something new for the kids, right? If not, anyone has a simple idea how to attach a small trigger lever to a standard rotary potentiometer for smooth, proportional control of the PWM signal going to the car?
 
Damn, I'd love to find something like this myself and play, don't mind me, I'm almost 45 (:

Anyway, you'll need a rotary potentiometer and a motor control module, which you can find in any hardware store, maybe even your local tobacco store. You'll also need a trigger and you can get as creative as you want, diy, 3d print or find one from an old rc remote car or something. Put everything in a case and you're golden. I would also add a spring to the trigger to make the experience better
 
Grab a cheap ebike thumb throttle or scooter hall effect throttle. They output a clean 0.8–4.2 V signal that feeds a basic PWM board perfectly and already have a nice trigger feel and return spring.
 
You can find finger trigger potentiometers or throttle potentiometers on eBay or AliExpress, and they usually cost less than $10. If you're into DIY, just mount a standard 10K potentiometer with a small lever arm on the shaft. A spring can help return it to the center position. A simple 555 timer PWM circuit works really well with Scalextric. If you're okay with basic coding, using an Arduino Nano makes things even easier.
 
I found my old micro Scalextric track stored away in our old house and I thought I could do some tinkering to make it work, maybe give it to my nephews. The plan is to build a PWM speed controller using a potentiometer shaped like a trigger. Anyone here have a clue where to find one that's budget-friendly? I mean, if it's breaking the bank then might as well get something new for the kids, right? If not, anyone has a simple idea how to attach a small trigger lever to a standard rotary potentiometer for smooth, proportional control of the PWM signal going to the car?
Cool project! I think the biggest challenge here is converting a linear pull into the rotary motion the potentiometer needs. If you're open to a simple and low-cost DIY, you can use a string or flexible wire attached to the trigger, which wraps around the pot's knob. When you pull the trigger, the string rotates the knob, and a small spring can pull it back to the starting position. This can be a bit tricky to get right, but it's a great low-budget option! Another idea is a mechanical linkage. You could craft or 3D print a simple lever that pivots to push on the pot's shaft. This gives you more control over the feel of the trigger pull. Both methods use a standard, cheap rotary potentiometer. I hope I explained them clearly.
 
You can find finger trigger potentiometers or throttle potentiometers on eBay or AliExpress, and they usually cost less than $10. If you're into DIY, just mount a standard 10K potentiometer with a small lever arm on the shaft. A spring can help return it to the center position. A simple 555 timer PWM circuit works really well with Scalextric. If you're okay with basic coding, using an Arduino Nano makes things even easier.
Thanks for the leads! Just would like to know though, how smooth is the response with a basic 10K pot and lever? And if we go the Arduino Nano route, can it handle braking too, or just speed control?
 
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