StoneAge DiskDrive Logo Turtles

StoneAge DiskDrive Logo Turtles

Never heard of Logo? Then visit The Logo Foundation

Turtle1 JPEG

The prototype - total weight: 800 grams
(the motors weigh 250 grams each!)

You could use it as the base of a mobile mount for a camera

Coming soon: The Return...

Ingredients

Two KP4M4-type stepper motors or similar, salvaged from "Stone Age" 5¼" disk drives.
An old IBM-PC power supply unit for +5v and +12v
Assorted plastic bricks, 4 cogs, 2 axles from that Danish Company
Two wheels from an old toy car
A section of a wire coat hanger (to prevent the cable dragging)
Sticky tape and foam rubber to taste
Here's the circuit I used

Patrolling the Lab

Control

Since the motors are mounted "back-to-back", they need to be stepped in opposite directions to move the turtle forward/backwards and both in the same direction to turn the turtle left/right. Because of the gearing, each wheel will turn in the opposite direction to its driving motor.

With coils 2 and 3 of the motors connected up as follows to an IBM-PC's Parallel Printer Port

       7   6   5   4   3   2   1   0   I/O Port              
     +---+---+---+---+---+---+---+---+ ========              
Data |   |   |R2 |R3 |   |   |L2 |L3 | Base = 278/378/3BC Hex
     +---+---+---+---+---+---+---+---+

These (repeated) Two-Coil Excitation sequences will move the turtle

Forward
Right Motor Anti-Clockwise		Left Motor Clockwise		Output Byte (Hex)
Coil 2	Coil 3	Coil 2	Coil 3	Output Byte (Hex)
1	0	0	0	20
1	1	0	1	31
0	1	1	1	13
0	0	1	0	02

Reverse

Right Motor
Clockwise Left Motor
Anti-Clockwise Output
Byte
(Hex)

Coil 2 Coil 3 Coil 2 Coil 3

0 0 1 0 02

0 1 1 1 13

1 1 0 1 31

1 0 0 0 20

Left

Right Motor
Anti-Clockwise Left Motor
Anti-Clockwise Output
Byte
(Hex)

Coil 2 Coil 3 Coil 2 Coil 3

1 0 1 0 22

1 1 1 1 33

0 1 0 1 11

0 0 0 0 00

Right

Right Motor
Clockwise Left Motor
Clockwise Output
Byte
(Hex)

Coil 2 Coil 3 Coil 2 Coil 3

0 0 0 0 00

0 1 0 1 11

1 1 1 1 33

1 0 1 0 22

Here's a simple QBasic Program to illustrate it all.

The ideal control language may be MswLogo - FREE from Softronics, Inc.

One of my project students gave the turtle a good SMACK

Stepper Motors Index

last updated: 8-Dec-98 Ian Harries <ih@doc.ic.ac.uk>

Reverse
Right Motor Clockwise		Left Motor Anti-Clockwise		Output Byte (Hex)
Coil 2	Coil 3	Coil 2	Coil 3	Output Byte (Hex)
0	0	1	0	02
0	1	1	1	13
1	1	0	1	31
1	0	0	0	20

Left
Right Motor Anti-Clockwise		Left Motor Anti-Clockwise		Output Byte (Hex)
Coil 2	Coil 3	Coil 2	Coil 3	Output Byte (Hex)
1	0	1	0	22
1	1	1	1	33
0	1	0	1	11
0	0	0	0	00

Right
Right Motor Clockwise		Left Motor Clockwise		Output Byte (Hex)
Coil 2	Coil 3	Coil 2	Coil 3	Output Byte (Hex)
0	0	0	0	00
0	1	0	1	11
1	1	1	1	33
1	0	1	0	22