profmason.com

March 8, 2013

Vexduino Working!

Filed under: Daily — profmason @ 6:10 am

I have been a fan of Robot C since Dick told me about it at the first Vex World in Northridge in 2008. I have taught a mechatronics course for the past 3 years for which ~30 vex 0.5 kits were purchased ~6 years ago.  These kits are superb and it is amazing how well the vex stuff holds up to continued student use.   However, the Pic 0.5 brains are showing their age, and several will no longer program.

Based on the motivation that the Original pic brain fits a very different niche then the current vex cortex, I designed a VEXDUINO shield that gives access to 6 digital, 6 analog and 6 motor ports in a format reminiscent of the pic-brain.  The board includes a screw terminal connector to connect a Tamiya connector to allow the use of existing Vex Batteries.

In combination with Robot C for Arduino, this allows the replacement of the classic Pic Brain with an Arduino + this shield.  I have a laser cut case in production, which means that my cost for this is about $30, significantly less then the pic 1.5.  In addition, we can hope that Robot C for Arduino will continue development.

Having received the Vexduino shields I had designed last month and soldered up the connectors.

I am happy to report that while using Robot C for arduino the board performs flawlessly.

The screw terminal package that I used was slightly different from the library but I made it work.

Items Tested so far.

  • 4  vex 3 wire motors simultaneously running from the external Vex Battery
  • 2 quadrature encoders
  • Vex touch sensor
  • Vex line sensor
  • HC-04 ultrasonic sensor
  • Vex ultrasonic sensor

To do:

  • yellow receiver module?

I have written code for decoding the TDM PWM signals used by the classic 72MHz radio control module.  Getting this into Robot C may be challenging given that it is closed source.

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