The Picobotz, has two photo-sensors for line
following, and so performs better than robots with just one sensor
which can only follow an "edge".
The obstacle sensor uses a very bright red
LED instead of an infrared LED (as does the line sensor). It works
surprisingly well and can easily detect obstacles up to 15cm away.
Because it uses visible light, it can also detect the general
illumination level in front of the robot. The circuit has been
optimised for detecting obstacles so, when measuring the
background light level, it is not very sensitive. However it can
easily "see" a desk lamp or a window
The microphone is good at detecting
handclaps but it can be hard to make a sufficiently loud "long"
sound - whistling works best. The sensitivity of the microphone
and the centre-point of the line follower, can be adjusted with
The length of a "long" versus "short"
sound, the threshold for the background light level and the
threshold for obstacle detection can all be adjusted in software
via a PC. The PC can also show a real-time display of sensor