Short-range (<50 cm) object detection and ranging

Dear all,

for my internship project I’m investigating what type of sensor is most suitable for the following specifications:

A robot (with a surface of 60x40cm) must detect an object within a range of 50 cm. Then, the robot must be able to manoeuvre around the object and continue to its goal. The robot will be used inside.

Obviously, I have been searching on the internet and questioned some people about which is best, but so far the options have been either Sonar (ultrasonic) or IR.

Because of its wide angle beam and the sonar not being dependant on lighting of the object or its surroundings, my preference goes to sonar, but i’m curious if there are more possibilities and if you guys could give me some more advice.

Thanks in advance for your answers.


Sharp’s optical distance sensors (e.g. are a nice alternative to the ultrasonic units, and they are relatively cheap, so you can get one and see how it works for you. They have a minimum distance, so you’ll have to set them back a bit to be able to measure from 0 to 50 cm.

- Jan