Computing stuff tied to the physical world

JeeBot Duo – in progress

In AVR, Hardware on Jun 7, 2009 at 00:01

To continue this bot-craze, here’s another design, the JeeBot Duo

More JeeBots in progress

This design is considerably more advanced. From left to right:

  • two 50:1 micro motors with wheels and encoders (Pololu)
  • a 6-pin FTDI header
  • the Baby Orangutan 328 motor controller (Pololu)
  • underneath: a low-voltage boost regulator (Pololu)
  • at a 45° angle: IMU board with 2-axis accelerometer and gyro (SparkFun)
  • a JeeNode v2 with on-board RFM12B 868 MHz radio module
  • underneath: a 860 mAh LiPo battery

It’s called a JeeBot Duo because there are two processors on board. The plan is to put the self-balancing smarts in the Baby Orangutan – which has all the hardware needed to connect to all sensors and motors. The JeeNode is available for telemetry, remote control, and perhaps to connect to further gimmicks later on.

Initial tests show that the motors have plenty of speed and torque, and draw 40 .. 300 mA each, depending on load. The boost regulator can produce a constant 5.4 V for the motors, while the battery level gradually decreases. There’s a tiny bit of slack in the gears, which translates to about 1 mm of slack/travel on the wheels.

The remaining space is for a compass module and an on-off switch. That makes this a relatively complete autonomous unit, able to sense its vertical position and change, as well as the distance traveled and the compass heading. With the proper software, it should one day be able to respond to commands such as “go 2 meter north”, or “drive around in a 1-meter circle”.

But that’s a long way off. Lots of tuning and software development will be needed to get there…