Parallax and speed controllers

[The Analog]

Has anyone use a Parallax basic Stamp/SX/Propeller micro-controller to drive a Jag or Victor? And if not do you think it would work?

[EricVanWyk]

Wow, that Propeller thing is... unusual*.

The propeller claims to be able to do 40mA per pin, you can probably do it by just putting a ~330Ohm current limiting resistor in series. If you are having trouble, consider putting a buffer in between.

You can see how the digital sidecar buffers its signal on page 3 of http://usfirst.org/uploadedFiles/DSC%20Schematic%20v7.pdf

Then it is just a matter of creating your PWM signals, which should be relatively straight forward.


* This (http://www.parallax.com/Portals/0/Downloads/docs/article/WhythePropellerWorks.pdf) document was my introduction to it. Wow.

[The Analog]

thanks for the link to the Digital sidecar, that really helps.

[Foster]

Basic Stamp will drive a Victor, so the propeller chip should also work.

There is huge forum for all things Parallax. Some digging came up with this post http://forums.parallax.com/forums/default.aspx?f=25&m=369650 that has code attached to it.

As always Google is your friend!

[keen101]

I once used an arduino to test our victors/jaguars once. It was great. It was fast and simple.

All i had to do was use the old <ServoTimer1.h> from ladyada and use the following code. http://www.ladyada.net/make/mshield/use.html

#include <ServoTimer1.h>

ServoTimer1 servo1;
ServoTimer1 servo2;

void setup() {
Serial.begin(9600); // set up Serial library at 9600 bps
Serial.println("Servo test!");
servo1.attach(10);
servo2.attach(9);
}


void loop() {
Serial.print("tick");
servo1.write(180);
servo2.write(0);
delay(1000);

Serial.print("tock");
servo1.write(0);
servo2.write(180);
delay(1000);
}

[Al Skierkiewicz]

Aaron,
The RC was originally a Basic Stamp in a special box and programmed in PBasic.

[engunneer]

Though in that case, the Stamp was running the user code, there was still another controller that handled all the PWM signals.

Oh, those were the days. 26 Bytes of RAM. Though there were a few bits here and there that you could use in an emergency.

Working on the Stamp based RC got me a job at Parallax for an internship.

A note to the OP. I'd recommend getting something like a serial servo controller, which allows you to deal with mutiple Jag/Victors using only one or two pins for serial communication. If you are using something like a stamp to control them directly, you may notice minor delays that can affect steering, since the control signals are not updated exactly simultaneously. Also, without the SSC, you have to constantly refresh the output signals, which makes the code architecture slightly more difficult. It can certainly be done, but the $30 add-on really makes it easy and powerful.