EDISON by Leonardo F. Urbano

EDISON the robot was a substantial leap from AMBER. EDISON was
equipped with sophisticated infrared ranging sensors and
simple photo sensors. EDISON would navigate through complex
mazes and find a medicine box sitting on top of an aluminum can
with a light bulb anchored to it. EDISON would get to the
aluminum can, grab the medicine box which would shut the light off.
Another alumnium can light would turn on at the opposite end
of the maze. EDISON would navigate to the new light source and
deposit the box on top of the can. EDISON was by far the biggest
and most complex robot I've ever built. He stood about 2 and
a half feet tall, weighed over 9 pounds, utilized over 129 wires,
elicited 5 behaviors and sank over 57.6 watts of power.
EDISON was an awesome robot. 

Specifications:
Body - black-painted plywood base with 3 stackable layers 

Electronics - 1 BASIC Stamp II microcontroller unit, 1 BASIC
Stamp stretcher board (no longer made), 1 Scott Edwards Mini
Serial Servo Controller, 2 servos for backward facing gripper,
2 servos for pan/tilt camera system, 1 black and white CCD
camera, 2 heavy duty DC brushless motors with wheel attached,
1 8-channel MAXX DUAL H-bridge motor driver circuit, 3 Infrared
Rangefinders, 3 photo-voltaic cadmium sulfide photo sensors,
1 2x20 character LCD, 3 9V batteries (one for Mini SSC, one for
STAMP2, one for B&W camera), 2 Ni-Cad 7.2v 2amp batteries wired
in parallel for drive motors, 2x10 button keypad, RJ11
programming port, and 6 sensor activation indicator lights. 

Time to Build - 8 days

Cost - $750



 The design made for easy programming, disassembly, modification,
 expandability and durability. An RJ11 jack in a box was
sticky-taped to the second level of EDISON's body. A 50 foot $3
phone line interfaced with the laptop for programming. You
could expand EDISON by simply unscrewing the bolts on the four
threaded rods and inserting another plywood plate. The frame
was strong enough to carry a laptop onboard.

One of the cooler parts of EDISON was the pan and tilt black and
white CCD camera. The camera was a hacked FisherPrice: My
first Video Camera toy for $30. Great for outdoor lighting, the
camera had awfully good picture for it's price. The camera
board easily interfaced with an AV cable to any standard TV or
VCR input. 

Metal detection whiskers - the robot has 2 metal detection whiskers
mounted on the lowest level of the robot in front of the
battery box. Each whisker is curled over the other for maximum
detection area. When both whiskers touch a metal surface, a
circuit is made. The stamp registers an impact with a metal object
by getting a +5v spike at the specified I/O pin. 

Photosensor - Three photosensors are mounted on top of the robots
body. They each consist of a single cadmium sulfide cell, 1
.1mf capacitor, 1 220ohm resistor and 3 wires: 1 to +5v logic, 1 to
ground and 1 as a signal line to the STAMP II processor.
The stamp sends voltage through the resistor, then counts how long
it takes to discharge, which is determined by the light
level. In this fashion, the stamp can measure light levels. Each
light sensor on EDISON had a corresponding green light to
indicate light detection.

Infrared Ranging Sensors - the IRPD unit was purchased at www.wirz.com
and comes with a 4-wire j-connector. It occupies 2 I/O
pins on the stamp. The onboard analog/digital converter sends back a
digital byte value of 0 to 255 for distances 0 through 4
feet. Only additional parts were two capacitors and some diodes. Each
IR sensor on EDISON had a corresponding red light to
indicate obstacle detection. 

Motor Driver - MAXX DUAL H-bridge - The robot uses a single MAXX DUAL
H-bridge motor driver board to drive the motors from a
signal supplied by the stamp. Four wires are connected from the MAXX
DUAL inputs to 4 I/O pins on the STAMP II. The four
output pins on the MAXX DUAL H-bridge are hooked up to the motors,
2 leads each. By throwing input 1 high and 2 low, a motor
hooked up to outputs 1 and 2 will spin. Reversing 1 and 2 will
reverse the motors spin. The same applies to inputs 4 and 3,
and outputs 4 and 3. The motor driver's supply is 2 7.2v 2amp
Ni-Cad batteries. The motor batteries are optoisolated from the
logic supply of the robot. 

The EDISON Robot was used in a series of experiments to test the
Taskable SOAR controller. The successful results of the
project were published in my Intel International Science and
Engineering paper. EDISON won 4th place at the grand awards
ceremony and over $2000 from corporate prizes. 

Visit my robotic homepage:
Leonardo's Workshop on the Web
www.ilrobotics.com

-Leonardo
9-1-2000


Email: stiglie@aol.com