Can It Be this SIMPLE? (the Off-Topic continuation)

[Mike_Lynch]

Melanie,

Thanks for explaining what you meant. My first reaction was to ask for a schematic,
but I want to stir some brain cells and actually THINK about what it is you are describing.
(Amazingly Sad how rusty I am on this stuff these days, if you don’t use it you LOSE it.)
I’ll have to sit down with pen & paper to see what I come up with before I come BEGGING
and have to bother you for a schematic. 8-)

Thanks
Mike_L

[Archangel]

When my Daughter was about that age I bought her a Suzuki JR50 motorcycle which she rode exactly once. Too much power and she bailed off never to ride again. So here's a suggestion: install a 1/4 inch headphone jack on the rear of this vehicle, break the power connection and wire it through the jack. the plug that mates gets a string attached to Dad or Grandpa. short the inner to the outer conductor of the plug. when it's plugged in he has power, if it gets away from him, the plug pulls out and it stops. You could get creative and use a shorting type jack so instead of stopping it switches to low power. I doubt
Dale Earnhart JR's. first ride was souped up very much.

RULE 1, SAFETY FIRST (Especially with kids)
RULE 2. Go back to rule 1

[Acetronics2]

Hi, Joe

I see something ... a DC motor Torque is a major function of the drawn current ...

soooo, limiting the Max current is a fair way to achieve your goal.

Now how ??? ... Mosfets have an internal ON resistance ... so, using PWM, just measure the D to S voltage, during the ON state ( 100% will also work ...), exactly as with a shunt ...
A simple comparator will short the gate voltage to ground if overcurrent... and allow to easily trim the limit.

That's what used on Power speed regulators for Electric models ...

now, you DO NOT have PWM aboard ... so, just sample D/S Voltage , say @ 500 hz to 3 KHz ( match to the motor ). Limitation will then be smooth enough.

Using a PIC to slowly automatically increase the PWM rate will add the soft start function ... and you've what you want

AND the MOTOR is SAFELY DRIVEN ...

Alain