Saturday, 20-12-2003

Today's entry focuses more on PC hardware than Lego!

If you a curious type, and have an interest in how machines work, like me, you'll have found homebrew designs and machines scattered across the Internet...
Stirling engines, Humphry pumps, wind generators, air muscles, muscle wires and the air car to name a few of the interesting topics that I've been able to easily research thanks to the Internet... (run a search on using these phrases and be amazed at what ppl get up to! The Air Car is in production with international licenses!!).

On one of my research marathons into how wind generators work, I found a website showing diagrams for the windings on an alternator using bi-polar curved shaped rare earth magnets...

A few weeks later my PC died... total failure of the C drive... a 7 year old Quantum Sirocco...
and being the curious type, I bought the right tools to dismantle the drive...
...I wanted to see if the drive motor could be used as a mini wind generator to power a Lego motor.

I still haven't tried making the mini wind generator, but Thursday night I had a 'bing' moment, the magnets and coil that move the read head arm inside the drive are the same shape as the coils and magnets mentioned above...
1...4 magnets and 4 coils could make a small alternator.
2...The magnet and arm setup was right for the movement needed to move a Lego Pneumatic switch.

I soldered some wire to the coils and a Lego 9v connector. I then tried it out with a 9v battery box (6x1.5vAA), the arm flicked back and forth nicely drawing about 0.6A @ 9v, so I perfomed some major surgery on the drive case... see below :)

Click on a piccy to open in new window.

Huge and heavy, my 5 way electronic air actuator works, off a 9v battery box, but not an RCX.
The connecting arm from the air switch to the hard drive arm is a length of thick piano wire.
The hard drive case... mostly :) CAUTION: the magnets from the hard drive are very strong. They can cause damage to electronic equipment and to fingers. J5's upper body structure, made from Lego Znap.

Very crude and expensive to run, heavy and inefficient... a bit like the Wright brothers first plane (100 yrs ago) or Mr. Benz's first car. Like these pioneers, my gadget works... HOORAY!!!

This is the first electro-mechanical device that I have ever built that did what I wanted... I did find a micro 5 way actuator available from a US website... $110, draws 0.1a and would fit into a 3cm cube... efficiency verses cost.

I didn't test the drive arm under load for the current needed, and the setup doesn't work using an RCX to control the drive arm... I remember from a website that the RCX max output for each motor port is 0.5A, just enough to move the drive arm without load :(

The next step towards an electronic air actuator is to find some 12v automotive relay units, and salvage the solenoids... small and low voltage, could they be used to open and close air valves?

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This page is part a diary of the design and build of my Lego Mindstorms robot J5 (based on Johnny Five from the film short Circuit.
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