toy rc car steering mod
I just got a sorta good used R/C toy car for $2, pretty nice for $2, and it works too
full suspension, differential drive, two speed gearbox, and the steering mechanism uses a servo
but this servo has all of it's control electronics out side the gearbox and on the single PCB the car uses. I just want to hack it so that I can turn it into a 2.4ghz (freebie RF modules from cypress yay) controlled "hobby grade" car with variable speed and such
this gearbox has 7 wires sticking out of it, 2 are to power the motor itself, another 2 is 6v+ and ground ( - ), the last three is a potentiometer in the mega ohms range, higher than 20 mega ohms for sure, because it goes out of my multimeter's range if it's at neutral, but goes to about 10 mega ohms when the wheels are turned
now, my datasheet for my PICmicro says in the A/D converter section "The maximum recommended impedance for analog sources is 2.5 kÃÂ©"
I can't really replace the potentiometer inside the gearbox, there is room for me to fit in my own, what would you do?
*add parallel resistors to the potentiometer (probably easiest)
*I can have a piece of paper shaded from light to dark and have a photo resistor tell me the darkness of the paper (might get jerky)
*I can probably directly attach a potentiometer outside the gearbox directly in line with the output shaft (durability issues)
*or I can put a gear on the shaft and have a potentiometer above the gearbox (I would need to cut my chassis to fit it)
what sounds good?