IR Sensor

I have been putting together an IR sensor based on this circuit:

Using a very small handful of cheap components, it seems to be an effective proximity sensor.

Here it is on the breadboard:

Testing showed that the sensor will detect objects within around 10 – 15 cm which should be fine for colision avoidance.

Due to the small number of components, it was easy to join them into a more compact in-line arrangement:

Finally, I heatshrinked the whole setup and added a 3-pin plug to make the unit more versatile and easy to change to multiple applications.

Using these sensors in place of the microswitch approach should enable the robot to navigate a space without having to constantly crash into objects. The IR will be affected by sunlight and other IR light so a more sophisticated circuit may be necessary in the future.