H-Bridge Motor Controller

After burning out the H-Bridge motor controller from Adafruit we tried the NYT version and had the same problem. We have started a new design based on the design by Radu Motisan at http://www.pocketmagic.net/. We have laid it out in Eagle and built it on a breadboard and its working well so far. We are trying to add forward and reverse LEDs before we move it over to a Radio Shack 276-150 board. If you need the parts list available from Mouser let us know.

C# "Software Joystick"

We've hacked together a C# program that writes motor commands like #+20-15; (motor 1 200 forward, motor 2 150 reverse). The serial port has Xbee connected to it. The only tricky part was the motor equations below.

double radians = Math.Atan2(dy, dx);radians = radians + Math.PI / 2;

m1 = (int)(Math.Abs(dx) * Math.Sin(radians) + Math.Abs(dy) * Math.Cos(radians));

m2 = (int)(Math.Abs(dy) * Math.Cos(radians) - Math.Abs(dx) * Math.Sin(radians));

(Equations from David "Wild Shot")

(ps: Its a Visual Studio 2005 project - We can post a copy once its been cleaned up.)

The Prototype "LV Tanker"

The first prototype with working Arduino, Adafruit motor shield, XBee, XBee adapter, motor power pack and 9V Arduino power, plus the Arduino sketch and Windows controlling program. The first try was buggy but working. Update: It turns out that the rechargeable power pack (from a swiffer) used to run the 2 DC motors was overheating the H-bridge on the motor shield. After switching to 4 AA batteries everything ran smoothly and we were able to drive it around the house.

XBee Adapter Kit

Making the XBee adapter ... about 1/2 done. After configuring with a TTL cable and testing the XBee adapter, the motor shield and the XBee adapter (both from Adafruit) were easy to get working together. (We were able to get analog pins 14-19 working fine as digital pins but could not get NewSoftSerial to read more then 2 chars in a row without errors so we went back to pins 0 and 1).

Fabricating parts

We have made 6 aluminum axils that are attached with nylon chain and turn in brass bushings. We are using nylon, aluminum and Lexan polycarbonate sheet to keep the weight down.

Initial Design

Prototype design of "The LV Tanker" - Blender perspective screenshot and underside render

The initial design done in Blender is a dual motor, 6-wheeled tractor controlled by an Arduino Duemilanove, remote controlled using XBees and a laptop. We are big Blender fans and have a lot of fun making things that are not real.