The Sound Box has had another update, and now includes an external speaker socket. this means that it can be plugged into an external amplifier/speaker or some other output device that can handle the analog signal. The image below shows the new jack socket with a device already connected via a jackplug:

In the next image a surface transducer (a surface speaker) is plugged into the Sound Box. The transducer itself is attached to a 1.2mm zinc plate with a strip of BlueTack. The transducer makes the zinc plate vibrate to produce sound.

The final image is a close-up of the transducer. You can buy these for around £5.00 each (or less) from many outlets on the web.

The next experiment will be to connect the Sound Box to an external amplifier, and from this to a much more powerful speaker. The speaker will be attached to a metal plate and we will look at how the sound waves propagate on the surface of the plate to produce patterns (visible using fine sand or powder).

For one of the forthcoming workshop at MERL, we might explore how potatoes can produce energy using a setup similar to this, and demonstrate that you can do more with a potato than boil it, mash it or make chips (french fries, if you are not from UK). The images below show the simple battery setup using a zinc plate and a copper plate with a small gap between them.

A potato (or two in this case for a larger current) is placed across the plates:

The current measured across the plates was about 160uA:

The next stage of development will be to drive a set of LEDs to indicate the current generated.

The (temporary) sound boxes have been updated so that they can be triggered via littleBits circuits. Each box now has two littleBits connectors at one end – one for input, and one for output. They have been tested using a simple toggle button on the input side, with an LED connected to the output: