Stepper motor gauges
Hello all,
I was wondering if anyone has tried to make a automotive gauge controlled by a BS2. I was thinking·it can be done if·I printed a gauge background and attached a needle to a small stepper motor. Of course this won't go in a car (no background illumination), but I was just wondering if anyone has tried to do this. How would one make a tach or fuel gauge? I know how to control a stepper motor, it's just the programming part (the pulses from the distributer and converting it to control the motor part) that makes me wonder. Thanks in advance.
I was wondering if anyone has tried to make a automotive gauge controlled by a BS2. I was thinking·it can be done if·I printed a gauge background and attached a needle to a small stepper motor. Of course this won't go in a car (no background illumination), but I was just wondering if anyone has tried to do this. How would one make a tach or fuel gauge? I know how to control a stepper motor, it's just the programming part (the pulses from the distributer and converting it to control the motor part) that makes me wonder. Thanks in advance.
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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
One thing you have to do, though, is zero the gauge upon powerup. This is accomplished by driving the needle against the lower pin, stepping it enough times that you know it's come around from its highest point. Since you'd be using a wimpy stepper motor, there won't be enough torque doing this to hurt anything. The needle, once it hits the pin, will just sit there and vibrate until you quit stepping it.
I did this once by converting a cheap outdoor thermometer to a gauge that counted people crossing the finish line in a 12K race. It was a pretty simple way to build a display that was visible over tens of feet away.
Another option would be to use a small RC servo motor and attach a needle to the control horn. You wouldn't necessarily have to keep pulsing it, assuming there was no ambient torque on the shaft, and it wouldn't need zeroing on powerup. Plus, no special driving circuitry would be required, as would be the case for a stepper.
-Phil