Arduino experiments at the Purley Hackspace

Last weekend our good friends from France stayed over at the Purley Hackspace. Fearnley and Pierre had never encountered an Arduino but were intrigued. With no programming or electronics experience the teenagers set about replicating the simple circuits and demos that come with typical starter kits.

Spurred on by their success, they proceeded through a variety of their own experiments, gradually integrating more and more functionality onto the board. 

It surprised them how tricky it was to develop the digital code that, combined with a simple 'push-to-make' switch, could turn into what they wanted: a 'push-to-make push-to-break' toggle switch. They also began to understand how integrating the code from one experiment, into another, was not trivial, and they eventually realized that the concept of an 'interrupt' would be very useful.

The pièce de résistance came in the form of a circuit with many features: on/off, speed control, colored LEDs and a chain of relays able to control any mains voltage device (up to 40 Amps) such as lamps, toaster, power tools, vacuum cleaner, cooker and beyond. Here it is controlling the lamp:

In another refinement, they added a light sensor and were able to activate the Arduino 'hands off' by turning off the main room light, with the effect of turning on the table lamp via relay chain. Pretty cool!




An 'end of day' final experiment which would have triggered a firework in the garden simply by turning off the house lights, failed to work. There was probably insufficient power to the firework-ignition circuit.