I have a DC Motor Speed Controller (PWM) that uses 100KΩ potentiometer to adjust motor speed. And I also have an electronic throttle pedal that used 49E Hall-Effect sensor (+5V, 0.8-4.2V signal, 1KΩ). I want to use this pedal with this speed controller.
I measured voltage drop on the potentiometer and it is 5V. Confirmed that pedal's signal changes from 0.8V (released) to 4.2V (fully pressed) when given 5V. What would be a right way to replace potentiometer in speed control unit with Hall-Effect sensor? Note, that I would prefer to preserve full speed control range (from 0% to 100%).
If you curious about my application – replacing binary on/off throttle in kids ride on car.
UPDATE 1
PWM controller built-in potentiometer works like that:
- Max speed: GND to wiper = 0V, wiper to V+ = 5v
- Min speed: GND to wiper = 5V, wiper to V+ = 0v
And Hall-Effect pedal is opposite:
- Max speed (fully pressed): GND to signal = 4.2V
- Min speed: GND to signal = 0.8V
So as drop-in replacement pedal will behave more as a break 🙂
UPDATE 2
On further examination, it appears that potentiometer's GND
(I mean, one of its legs that I referred above as GND) is connected directly to input GND
of PWM controller (where negative terminal from battery goes). So, from practical standpoint, it's probably safe to assume that I also have GND
– Xv
at my disposal (Xv
however is variable, since it's coming from unregulated battery). But I think this extra voltage source makes this question less general and less useful for other people…
Best Answer
simulate this circuit – Schematic created using CircuitLab
This won't reverse it. Will continue to look at it tommorrow. I'm not sure I can do it without a negative supply.
https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWEA2AzNA7ATi8gHACxhaKTJYgIaWWQBQAhiAEx57hbMgGpfFfswSALRDw8eFGi5myBGDxyCyMs1QUYM5GhwZlYDAlbiJdAO4s24MF1aCMyKOe68OXHnxtOATpcFePay5IcAR4Ol8bf1srMC8QsFNfOxZIdhTmBEcEsLg6AHM-Fiyi1EgCHyLmNLdU9gTTAHkXPk5uXFqQ+gAHWurBNszsqCdC-mLHcbKK+gA3cGMhhfSakIqCBMwWaCQunYLlicPmDGCDqPAVQ4Ns5wv+vtW6VBnoPAA1AB0AZwAvAFMAHb-XybDBgHhGPD8aHwZj-YTUELBN50X7XK4XOK2KQfH4A4HeCLXLwXAj1EDqPIAJUO5IxIzWIV2jP2AHsQBRkDNuJAsOwkbB4FgHFlMiMwHQOexuSMNvzxFIJMwCEQNshxRBJUA