Building a Contact Microphone


Equipment:	www.allelectronics.com

soldering iron & solder
epoxy

35mm Piezo element w/wires 		PE-44
22 guage shielded cable w/drain		2CS22
1/4" mono connector plug		SPH
outer heatshrink tubing			HUG-18
inner heatshrink tubing			HUG-116


Instructions:

1)  Prepare the piezo element by twisting the red & blue leads together.

2)  Prepare the cable by stripping both ends to expose a positive, negative & 
shield (drain) wire.  On one end (the side for the piezo element), cut the shield off 
completely.  On the other end (for the plug), twist the shield around the black wire.

3)  Unscrew the plastic casing from the mono plug.  Attach the black wire & shield to 
the larger connection point of the plug (sleeve).  Attach the white wire to the smaller 
connection point (center). Solder to fill all holes completely and cement the wires in place.  
Screw the plastic casing on again to complete the plug.

4)  Place the outer heatshrink tubing over the wire and leave at the bottom near the 
plug.  ItŐs important to do this BEFORE soldering the piezo leads to the wire.  Also 
slip the inner heatshrink tubes over the black and white wires that will be soldered to 
the piezo leads.

5)  Twist the white wire together with the blue & red piezo leads, and the black wire 
with the black piezo lead.  Solder the each of these connections to keep them in 
place.

6)  Use a hair dryer to shrink the inner heatshrink tubing over these solder points, 
then slide the outer heatshrink tube up to the piezo element and shrink it.

7)  Finally, apply a glob of epoxy over the solder connections on the piezo element 
itself.  This will protect its fragile connections from being broken.