Building An Obstacle Avoidance Robot

Just for kicks, I decided to build an obstacle avoidance robot.  That is, a simple robot that will drive around, and if it encounters something in front of it, it will turn and drive in a different direction to avoid it. While this is a fairly simple start, my plan is to use this as a base and incorporate some more advanced functions as it develops.  But for starter it's a simple problem with a well understood solution.

Here are some early thoughts about the robot.

The robot is based around a three wheel design, where the front two wheels are driving, and the third rear wheel is just a castor for balance.

It will use an Arduino for control (just because I have one spare).

The propulsion will be from a pair of simple gear motors, using differential drive to turn.

As the wheels do not have any rotary encoders fitted, I may end up using a single axis gyro to detect the rate of yaw to help keep the robot in a straight line (and to help it turn). But i'll see how t goes without it.

For vision I am currently deciding between an ultrasonic ping sensor, and an IR sensor.  Again I haven't decided which I will go with.

I have drawn a quick model in OpenSCAD to try to illustrate what I am thinking.