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View Full Version : [Question(s)] BS2 to Duratrax Sprint interface



butchalline
11-04-2008, 06:52 PM
The Duratrax Sprint ESC (used on R/C cars) is cheap, can drive a brushed motor forward and reverse, and can handle 12 VDC input. I'm trying to get a Basic Stamp to control the Sprint but can't get it to work. It controls a motor just fine when controlled by an R/C receiver.

Has anybody done this? Any ideas?

Thanks

jes1510
11-04-2008, 07:27 PM
I've never actually used an ESC with a micro but you should be able to control it just like a servo by varying the pulse width between 1-2mS with 1.5mS being stop (or thereabouts). This should be repeated every 20mS.

Edit: You may need to apply low throttle first to arm the ESC and wait for a little bit before increasing throttle. That is how my airplanes work.

One more edit: You may have to apply 1.5mS pulses first since this ESC was designed for cars instead of airplanes.

Here is the manual for your ESC:http://manuals.hobbico.com/dtx/dtxm1200-manual.pdf

Adrenalynn
11-04-2008, 09:33 PM
I concur, Jes. From the manual:

"Make sure the throttle trigger is in the Neutral position before turning on the ESC.

1) With the transmitter throttle trigger in neutral, turn on the ESC. The
green LED will light up for about 1 second.
2) Pull the throttle trigger to full forward, the red LED will light up to
indicate the full forward is now being operated.
3) Push the throttle trigger to full reverse, the green and red LED will
light up to indicate full reverse is now being operated.
4) The ESC will hold this setting until it is reset.
5) Repeat this procedure if any or all steps fail to operate as expected.
(Note: The motor does not function during the set-up process.)

So the BS needs to send a 1500uS pulse repeatedly until after the ESC is switched on. Once it sees the 1500uS pulse, the LED will turn green for about 1Sec.

THEN

The BS needs to send a ~2500uS pulse a few times. Might not like more than 2100uS, but I'd try 2500uS first myself (more granularity of control later if it works). The Red LED will light.

THEN

The BS needs to send a 500uS pulse a few times (might not like less than 900uS, but again as above, I'd try 500uS first). Both the Red and Green LEDs will light.

If it doesn't happen this way, the process needs to be repeated until it does. Rinse, Lather, Repeat as the shampoo moguls would have it. ;)

I would probably put a potentiometer on an analog pin and scale 0 = 500uS to 1023 = 2500uS myself, and mark the 511 spot as center. Then you could have a calibration routine that you could call on the BS whenever you needed it. Bonus points for adding a momentary push-button to send 1500uS whenever it's pushed.

Oh, and WELCOME to the TRC!