TinyTim by David Buckley
| May 1994
|
- A sub miniature self contained robot vehicle
with onboard computer programmed in a high level
language, capable of seeking light whilst
avoiding obstacles. Uses a five layer behavioural
control program.
Built May 1994.
Size - 1.5" * 1.9" * 1.3".
(yes, that is 3.8cm * 4.8cm * 3.3cm)
Operational area - 6" * 6" minimum.
On 20th May 1994 Professor Rodney Brooks gave a talk at the Royal Institution, London, about using robots to explore Mars, at which he demonstrated two hexapods. I built TinyTim hoping to use it as a sort of introduction but after the talk he was surrounded by lots of people clamouring for his attention and although he saw TinyTim we only exchanged a couple of words.
Tiny-Tim has is controlled by a Basic Stamp1 chipset from Parallax and has two forward facing Light Dependent Resistors (LDRs) for eyes, two front wiskers and one rear bumper for obstacle detection, and a small square cut from a piezo sounder soldered underneath the circuit board so Tiny-Tim has a voice. It now runs off three 1.5v Silver button cells athough originally as in the picture it ran off three 1.35v mercury cells. Initially I was worried about how long the cells would last and chose the mercury cells because they were larger, however their combined voltage of 4.05v was not really enough and the the Stamp crashed occasionally. Changing to three silver cells upped the voltage to 4.5v and Tiny-Tim is now reliable. The wheels are filters from water-taps (faucets) with glued on 'O' rings for tyres and the front castor is a cut down drive wheel from a micro-cassette deck. The motors and gearboxes were bought from Conrad on a trip to Munich and run at about 18mA. They are driven directly from the PIC controller of the Stamp, each motor being driven by two pins of the PIC as a H-bridge.
connected@telegraph.co.uk - The Daily Telegraph, Tuesday 2nd July 1996