Hi guys,

This is my first post on the forum, and hope someone can help. I've been
through the threads and haven't found a solution yet.

I have, amongst other r/c aircraft a Dragonfly 2 channel helicopter,
really just a toy. Controls presently are up, down, hover, spin left and
right. Although described as a 2 channel control, chips used are the
tx/rx-2b 5 function job designed for toy cars. Data sheet is here

http://www.datasheet4u.com/html/T/X/...ctors.pdf.html

It occured to me that if one of the functions could be made proportional,
it would leave 2 spare channels to control direction (currently not available).

Early experiments are good. Replacing the original full speed on/off
switch in the transmitter with a PWM circuit to control the main motor
works, the motor speed being truly proportional, giving much better
control. (so far without any changes to the receiver end). I'm keen to get the directional problem sorted.

However there's one snag with the circuit I've used. If any part of my
body gets too close to the circuit (or the aerial), the motor spins up to
full speed, dropping back to controlled speed if I move away again. Some
sort of capacitance problem but although I can find my around a circuit
board, I'm self-taught over many years but not clever enough to know what
to look for. I've tried various decoupling caps etc to no avail.

If anyone can help I'd be much obliged.

Davegriff

Sorry, I've posted this twice.

Attached Images

circuit.jpg (28.5 KB, 6 views)