Shop OBEX P1 Docs P2 Docs Learn Events
Modulated Light Beacons for Orientation in a Room — Parallax Forums

Modulated Light Beacons for Orientation in a Room

Christof Eb.Christof Eb. Posts: 1,463
in Robotics

Hi perhaps someone has done something similar or has some other comments? - Thanks in advance!

Idea is:

  • A robot is moving inside a room.
  • Goal is to have position and orientation.
  • It has a fototransistor mounted similar to the robots having a ping sensor, so that it can be turned horizontally with a servo motor. Actually the idea is to use the same servo. The fototransistor is sitting in a tube, so that it's angle of vision is limited. - A 1 pixel camera.
  • In the room there are at least 2 light beacons, which each have a light (preferable visible). These lights are modulated as square wave blinking on/off but the two (or more) beacons each have their own frequency, to be able to distinguish them.
  • The signal from the fototransistor is high pass filtered, amplified and fed to a P2 ADC then filtered again either with the Goertzel Smart Pin Mode or with Goertzel Software working on a sampled buffer.

I had done something in this direction using a camera some time ago. It's frame frequency was low and the blinking frequency was also low. Now I am more thinking of something like 10 kHz.

The method seems to be interesting, because a beacon can be build cheaply and the hardware on board of the robot seems also to be very simple, if the P2 can do a lot.

Of course wondering about resolution and possible range.
Cheers Christof

Comments

Sign In or Register to comment.