Five years ago, back when I was making a load of Contact Mics, I soldered some guitar string offcuts onto the back of a C-mic and enjoyed the plinky fun sounds that resulted:
Recently someone reminded me of these and I thought I'd make a new version mounted in a little box. Here's a simple DIY guide to make your own (click images to enlarge):
It is a very simple setup - a c-mic mounted inside a little box with some guitar string pieces (c. 6" length) soldered on to the back of the c-mic.
I used some plain and some wound guitar strings of various diameters - you can experiment with different gauges and different lengths.
The only slightly tricky part is how to effectively solder the strings onto the back of the c-mic - what is important here is to get decent heat-transfer - make sure your soldering iron is as hot as it can be (I turn mine up full) and that it is clean.
- I first make a blob of solder on the back of the c-mic, about 1cm diameter
- I then tin the ends of the guitar strings
- clean the iron tip and re-tin it, but with quite a lot of solder
- now re-melt the solder blob and fuse in the guitar string
- repeat for all the other strings, spacing them very slightly apart from one another
- you can see in the 2nd image how I stripped back the ends of the wound strings to expose the plain central core
I mount strings onto the c-mic and then use epoxy resin (araldite etc) to fix the c-mic into the plastic case.
The Piezo element is just a standard 27mm piezo disc.