RE: motor control

["Steve Tyng" <stevet-at-stcharlesmd.com>]

>what are you guys using for motor control? I am planning on using 4 lawn mower 
>starter seinoids. 2 for foward and 2 for reverse. Do you guys think this will work?

I initially had installed electronic speed controls (ESC's) in the T005 that were 
attached to a mixer (for one stick steering).  This didn't work as well as I had 
hoped.  I am now building a relay based control system with a custom programmed PIC 
microcontroller to handle the mixing.  Starting relays will work, but if a recall, 
these are simple on/off relays (single pole/single throw or SPST) which means you 
will need four for each motor.  They will have to be setup in an H-Bridge 
configuration for forward/reverse control.  If you use single pole/double throw 
(SPDT) relays you only need two per motor.  Standard 40amp VF4 series automotive 
relays are SPDT.  Their cheap and readily available and are what I'm building T5's 
new control system around.  If you want to get fancy you can base your control 
system around solid state relays.  This is what Joe is doing with his "Stealth 
Hezter".  With solid state relays you can also pulse-width-modulate (PWM) your 
driving current to control motor speed.  This is how ESC's work.

Check out Franks excellent article on speed controls in the how-to section, 
particularly the section on the MAG speed control (not really a speed controller but 
a 'direction' controller).  In the warship world where the MAG speed control came 
from, speed is controlled by moving the transmitter stick rapidly back and forth - 
turning the motor on and off (a form of low frequency PWM).  A web search and a 
little research on H-Bridges and PWM is recommended for those not familiar with the 
concept.

Steve Tyng