Crawly Number 1

My First One
Two Motor WalkerSchematic
This one has a movie1.37MB MPG Movie, 320x200 resolution, 15 seconds..
Nihon Mini Motor Bug
The Gear SetGear Modifying Instructions.
Bridge Head
CyberArm revisited

Symet Page
Turbot Page1.37MB MPG file, first one.1.37MB MPG file, second one.
Biggie Page
Slider Pagewhine-whine-whine-WHINE-WAV file, 76K.Not Available Yet.
PIC-16LF84 chip, emulates a microcore.Schematic - JPEG image 925 x 683 pixels.Source file for GP16LF84.Hex File for programming into PIC-16LF84-04/P
You're already there!

On 3/17/2001 I added the last leg but haven't updated the pix.

On 3/21/2001 it walked! Kinda slow, but could be sped up with system tweeks.
I doubled the springs to the front knees as they were much softer and smoother in action.
The circuit boards and batteries need to be mounted in some kind of final positions.
The small brass rods that connect the two center motors together need to be stiffened
as it flexes too much.

Here is a new style of leg assembly (maybe)? It only has three legs for now, since I ran out of brass tubing. (I need a tire jack ! haha). This "crawly" is spring loaded to maintain clearance underneath.
click for larger 994 x 555
Side view. Shows only three legs, of course. The leg on the left, the one by itself, has been shortened. That's a brass thumbtack on the leg bottom for a "foot". You can see another DC motor in the back, used for a "tire jack", holding up that space where the last leg goes. The front pair of legs was constructed first, then the back set, the unfinished one.

click for larger 675x 663
Partial front view, everything "centered".

click for larger 410 x 471
Here is a shot of the inside of one leg (left front). Those legs are umbrella ribs.

click for larger 1152 x 768
Shows the center motor to one side (legs moved to your left).

click for larger 152 x 768
This shows the center to the other side (legs moved to your right).

It is mostly constructed with hobby brass tubing except the silver legs are unbrella ribs.
The springs came from an Ace Hardware $3.99 spring assortment blister pack.
Center gear-motor moves the whole leg assembly back and forth.
Each knee motor moves its' own leg up and down.
While building it, I realized that the knee motors don't need to be at the "knee" but could be at the "hip" instead. So that's where I put the "back-leg" motors.

The hexcore is a 74HC14.
Resistors are 1M with a 1M POT for speed control, caps are 0.22uF. The pot is set to about 400K.
74AC245 driver for all motors, no reversing for the current build.
Incluced are LED's to see the motor cycles running and to verify that it has only one cycle circulating.
The hexcore is wired as per Wilf Rigter's PNC version, with the exceptions of the resistor values.
Note: it takes 5 cycles of pulses to clear it, with each power-up. On the sixth cycle it is running at cycle #1.
So it does a little "dance" while getting ready to walk.
Thanks to Wolf Rigter!

Front legs:
Right front leg goes up, left front leg goes down, center rotates ccw (counter-clock-wise).
This pulls the left front leg back and moves crawly forward.
Right front leg goes down, left front leg goes up, center rotates cw (clock-wise).
This pulls the right front leg back and moves crawly forward.

Motors are numbered starting at the left front, #1.

Left Front is # 1
Front Motors
1 2 3
1 D
2 U
4 D
5 U
6 CW
Rear Motors
4 5 6
2 D
3 U
4 CW
5 D
6 U
Orange, Rows are HexCore states.
Blue, Columns are motors action.

Paul T. Barton

This page updated: February/07/2002