Alt-BEAM Archive

Message #03297



To: beam@corp.sgi.com
From: Steven Bolt sbolt@xs4all.nl
Date: Sun, 16 May 1999 14:00:29 +0200 (CEST)
Subject: [alt-beam] The final SunEater



SunEater_V uses a single 74HC14 to do all his "thinking." Two
Solarbotics "tiny pager motors" provide the muscle. Together with
SMT components, they allow SunEater_V to fit in a 3.5cm x 2.7cm
x 2.5cm block, with just his wheels and feelers sticking out. He
weighs less than 14 grams.

The SunEater_V behaviour is based on three rules:

1. If no feeler switches are closed, the motors will obey the `eyes'.
SunEater_V moves towards the best light, while trying to avoid shadow
patches.
2. If one of the feelers touches an obstacle, SunEater_V "follows the
wall" in the direction of the better light. Both this and the first
behaviour are illustrated here. Thanks to the `mechanical memory' - the
robot keeps a feeler in contact with an obstacle during evasive action
- the motion remains deliberate, even if the voltage drops to zero
between steps.
3. With both feeler switches closed, the robot will push against one of
them, trying to get free.

SunEater_V is the smallest and most active of my photovores. With
the sun about 30 degrees above the horizon, its horizontal BP243318
(24x33mm 5-cell panel) supplies enough power for two or three
`steps' of about 0.5cm per second. When the sun gets higher, the
robot achieves several cm/s. And even in the shade there is motion
every few seconds. Photos, schematic, PCB layouts and everything
else you might need to build something like it can be found on:

http://www.xs4all.nl/~sbolt/Other/suneaterV.html

This is probably the final SunEater. The most BEAMish of my next
projects is the Robotic Easter Egg Hunt :)

Best,

Steve

----------------------------------------------------------------------
# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
----------------------------------------------------------------------




------------------------------------------------------------------------
eGroup home: http://www.eGroups.com/group/alt-beam
http://www.eGroups.com - Simplifying group communications

Home