Your name or email address: The P5v2 5-motor walker circuit An overview of the P5v2 walker electronics by Wilf Rigter – Feb This description of operation must be used with the schematic and layout drawing shown below: Both outputs oscillate If both photodiode s get equal light, the two inverter complementary outputs are pulsing and neither of the slave bicore s is reversed causing the walker to go straight. A schematic is available. The ‘ is an octal buffer chip, and so has 8 channels of buffer ing power available for our misuse. The body of the rotating part is a hard drive head mechanism, which happened to fit nicely over the pinch roller hub. And if yes, what would it be?

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74AC240 replacement

Since the bot has two solar cells, I could replace the photodiode voltage divider in that circuit with the solar cells themselves, by taking mofor reference voltage from between the two cells which are wired in seriesvia a large resitor.

Look no further because the Trinket has got you covered. May 23, 4.

This causes the legs to both move forwards or backwards together or to rotate the body of the walker slightly with each step of those legs until the light level is balanced on the two photodiode s. The circuit is described at the Solarbotics site see schematic for a similar design that uses recharable batteries in place of the capacitor.

The goofy rubber tires fit over the ends. The Power Supply The last part is the power supply which consists of a 6V NiCd battery pack and a charger circuit designed to be used with a wall type AC adapter.


The inverters used for reversing are turned on or off with the tri-state enable pin The vertical chassis is from an old VCR.

The “BEAM Stepper” drive circuit

There are two 74ACs: The 78M05 regulates output voltage to within mV i. No, create an account now. Q1 being ON grounds R1.

This 74ac24 octal 8 channel inverter chip is more power efficient than the AC series, but can’t drive as heavy loads. The results are quite pleasing, and this is quite an active little guy. The LM is tucked above the blue trim 74ax240 I flattened the pins to make it sit flat. Of the three style of 74xx chips, the AC style has the greatest driving current at the cost of higher switching noise and channel cross-coupling having one channel’s signal interfere with another channel.

This technique was simple to apply to the bare bones head circuit too with the modification suggested by Wilf Rigter here. Three times drive current of HC, draws over ma power supply 74av240 input at switch point. A high voltage on those pins would be a low voltage at buffer’s tri-state controls and would turn the buffers off.

When the light is balanced pin 19 of U6 motorr U7 are both high, both reversers are turned off, the tristate inverter s are disabled and the walker moves straight.

See the data sheet for yet more details on this chip. You can see the solar engine here: Because these suck up a fair amount of juice, this pummer only runs for about an hour after dark.


This current will be greater than that which can be absorbed by R3 and the excess will turn Q4 ON causing current to flow in R1.

The chip is a 74AC May 23, 1. I used some salvaged surface mount components for the solar engine capacitor and diode, which make the SE nice and small, as shown in the second photograph.

AT90S Replacement Posted by lubnaan90 in forum: Depending on the phase angle of the waist motor, the legs are lowered on the floor on the front or the rear stroke of the legs and therefore determines the forward and reverse direction. The ouputs of the HLO are connected through diodes to discharge capacitors on the tristate enable pin 19 of the reverser circuits in U6 and U7. With less light pin one rises above the threshold and becomes high.

The reversers between the master and slave bicore s determine whether the front and rear legs on opposite corners are moving in the same or opposite direction when the legs are on the ground. The result is a dual solar panel head, with no additional photodetectors. K This circuit has greatly improved sensitivity in low light conditions.

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