Are you hot to trot, wanting to start playing with your new
MIDI Drum Kit? Let’s get started with building it.
Following on from the circuit description of the SILICON
CHIP MIDI Drum Kit in the first article last month, we shall now describe the
construction of both the main unit and the different types of sensors.
This shot clearly shows (a) how the
two PC boards are piggy-backed together, and (b) the many holes in the box which will have to be drilled very accurately. The cutout for the display will differ according to the brand of display.
The unit itself is constructed using two PC boards, the main PC
board (coded 01211051 and measuring 187 x 104mm) and the display PC board (coded
01211052 and measuring 140 x 100mm).
The assembled PC boards are fitted, one on top of the other,
into a plastic box measuring 197 x 113 x 63mm. The box is actually used
upside-down; that is, the normal lid of the box becomes the base and the display
board sits in what would normally be the bottom of the box – turned upside down,
it becomes the top! Confused? It will all become clearer as we proceed . . .
Before starting construction, check the PC boards for correct
hole sizes and that there are no breaks in the copper or shorts between tracks
or pads. Hole sizes for the corner mounts on the display PC board and for the
LCD module should be 3mm diameter (~1/8").
Check that the mounting holes for the external jack socket,
the DC power socket, the DB9F serial connector and the MIDI output socket
are all correct. Finally, the main board has four corner cut-outs, which you can
clearly see in our photos, to enable it to fit snugly inside the box mounting