Monday, 13 June 2011

First Joule Thief circuit

It's amazing thing seeing a 'dead' battery produce useable power!

Alternatively, using this circuit, you can use a regular 1.5V AA cell to light up a white LED which normally only wake up at around 3V.   Very clever!

To learn the how and why of it all, visit Wikipedia

JP helped me do the soldering on this.  He was in charge of the solder (new lead free solder by the way).  I plumped for a big fat ferrite core that I had lying around.  It can be done with teensy tiny cores but I didn't fancy the fiddle - especially with JP and it being my first attempt.

The circuit is built freeform - that is to say without a circuit board.  Heatshrink comes in handy here.  It fired up first time.

Here's a trace of the waveform on the oscilloscope.  If I'm reading it right, it's peaking at around three volts.

The AA cell, under load, is putting in 1.3V at about 40mA

Putting the 'scope into XY mode produces this gorgeous trace.  Fascinating - especially when you realise it's running quite fast... by my calculations, this is running at about 70kHz — 70,000 pulses a second!

For thems that wants to know mores...  I was following the circuit diagram and recipe here.


Friday, 10 June 2011

Guernsey Racing Limpets™

You saw it here first folks!

If you want to learn to how to build a Racing Limpet contact Gen at and sign up for my Limpet Racing Masterclass (should be on Sun 31st July).  I can't wait!

Thursday, 9 June 2011

ArtBot making

I'm soon to be teaching a class of children how to make ArtBots — a type of vibrating robot that has felt-tip pens for feet.  Fun fun fun!

Alternatively, the 'bot can be decorated and dressed up as a weird and wonderful new creature the world has never before seen then left to explore it's new environment.  Sort of a robot pet.

To be a part of the fun contact Genevieve at