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

[Jansuhn]

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.

 

[cr0sh]

What you may want to do is use multiple types of sensors; use sonar, use IR, and add some bump/whisker sensors (just in case things get past the sonar and IR). Integrate the readings from all the sensors so that if one fails to pick up an object, the other might and you'll still detect it (worst case for the sonar and IR would be soft fuzzy black pillow).

You might also want to add a camera (or two) and experiment with a vision system (your robot sounds rather large - so there should be room and power available for the cameras and computational needs). Also look into SLAM (Simultaneous Localization And Mapping)...

 

[FreeRideSkier]

I've been using an IR detector (Sharp GP2D12 IR Sensor) which seem ok between 20-40cm. The key is to mount it on a scanning servo so that you can detect the edge.

Using ‘FlowStone DSP’ software I set five scan fields for the servo and decoded them into Left, Left-Mid, Middle, Right-Mid, and Right. This way my bot could decide to back up and turn or just side step to avoid the obstacle.

 

[misterT]

Silicon labs have some great looking IR sensors. They are designed for user interface products and can detect 2D position of an object. I think they could be used in a robotics application also.

Infrared Sensors
IrSliderEK