SEEKBOTS
SEEKBOTS is a collaboration with Nicolas Munoz for the Communicate project. The idea is to create two robots, one which can move but has no sensors to find its way while the other uses an ultrasonic rangefinder to scan its surroundings but is immobile. The goal is for the moving "Seeker" robot to locate and unite with the "Beacon" robot. The robots communicate through XBee transceivers so that the Beacon can call out to the Seeker, telling it if its going closer or farther away.
The communication is primitive yet effective - every time the Beacon detects the Seeker it compares the new distance reading with its last reading. To be able to detect the Seeker the beacon spends a couple rotations when it is first turned on to calibrate to its surroundings, finding the closest position which should be ignored. Anything within this max distance is considered to be the Seeker robot and then Beacon will send out a signal to it. If the distance between the robots is decreasing a "1" is sent indicating to the Seeker to remain on course. If the Beacon detects the Seeker to be moving farther away then it sends a "0" and the Seeker will reverse direction. If two reverse directions signals are sent in the space of four communications the Seeker will make a 45 degree turn and restart the procedure.
In the photographs below are some long exposure shots of the robots in action where LEDs in their circuits leave trails of light. You can see some of the movement patterns that the Seeker makes on its journey to the Beacon, unfortunately a max exposure time of 15s was not enough to see the robot complete its travel in most of these shots.
SEEKBOTS from Peter Rockwell on Vimeo.
