WALLY

This is how it started off. I had to put the balance spring in as otherwise there would be no possibility of any kind of walking gate. I wanted to do it with    circuitry but the consensus of opinion was that it would not be that easy.

Once the frame and gate were to my satisfaction I went on to the circuit.

This is how I decided to lay out the circuit on the strip board. I have learnt from other bots that sockets and pins are a must if you want to be able to tinker with values. The left socket is the Master/slave bicore and the right one is the motor driver socket. If you look towards the bottom of the page you will see the schematic. I used the  Almost Complete Walker circuit, the 74AC245 driver circuit and the Miller Solar engine.

This is how it looks once it is populated with the components. Far left is the Miller engine then the ACW and finally the 245 driver. The cap is a 1F 5.5v memory cap from Maplins. After this was taken and the bot put together I added a second 1F 5.5v cap. This gives him more of a kick to start and his steps are higher.

The values I have indicated are just the values I find work for this particular bot, experimentation is half the fun!

 

Values for ACW circuit

 

Yellow = 1 x 10uf cap

Red = 3 x 1.5meg res

Green = 2 x 47k res

Blue = 1 x 2.2meg res

Pink = 4 x 0.22uf caps (224)

 

Values for Miller engine

 

1381 Q     (3.8v trigger)

2n2222    (or 2n3904)

2x 1F 5.5v    Memory cap

SC3766   5.5v solar cell

33uf timing cap (this is what I ended up with although the diagram says 47uf) Trial and error!!

Values for M1 & M2

 

2 x nihon mini motors

(AKA BG Micro motors)

On the left you can see the motor         connections  and the yellow tactile sensor wire. The round white bits under the pcb are pieces of rubber tube to keep the board from shorting on the metal base.

The right hand photo shows the Miller    engine and the 33uf timing cap. The black lead going off to the left is a separate earth for the tactile sensors.

He looks quite bug like from above, although he is quite tall really.

I first used the 74HC245 driver but found he would only vibrate on the spot. I adjusted the timing cap and this allowed him to take 4 steps per pop. I decided to try the AC instead and to my  amazement he now walks about 11 steps per pop. When I get some real sunshine I will try a bit more tinkering to optimise this.