Following the circuit description of the MIDI Theremin in the first article last month, we shall now describe the construction and setting up procedure. Software will also need to be installed and to do this you’ll need to download some files from the ’net.

Firstly, though, let’s start building the MIDI Theremin.

Construction.

The SILICON CHIP MIDI Theremin is constructed using two PC boards. The main PC board is coded 01204051 and measures 187 x 104mm, while the display PC board is coded 01204052 and measures 142 x 99mm. The assembled PC boards are housed in a plastic box measuring 197 x 113 x 63mm.

Begin construction by checking the PC boards for correct hole sizes and that there are no breaks in the copper or shorts between tracks or pads.

Ludwig van, eat your heart out! You can become a composer with the MIDI Theremin and sequencer software!

Hole sizes for the corner mounts on the display PC board and for the LCD module should be 3mm diameter (~1/8"). Check the mounting holes for the external jack socket, the DC power socket, the DB9F serial connector and the MIDI output socket are all correct.

Check also that the PC board to fits into the box neatly at the side pillar clips without bowing the box. If the box does bow out, the edges of the PC board will need to be filed off by a small amount so that it is a better fit.

We assume that the Theremin is being built from the Jaycar kit (the only place you can get it!) – in this case all the holes in the box will have been milled out and a screen-printed front panel will be supplied.