For this you will need:
- A Box (small, chunky and sturdy is best)
- A wooden stick of some kind (could be a mop handle, dowel, again anything sturdy) All i happened to have was some bamboo from grandmas garden.
- 1 long bolt with 2 nuts to fit it
- 1 piezo transducer (I think in the states you usually buy a buzzer and take it apart, here in the UK we have maplins who sell them naked - http://www.maplin.co.uk/piezo-transducers-3202)
- 1 1/4 inch mono chassis socket (again, maplins comes in useful http://www.maplin.co.uk/1-4-mono-chassis-socket-1252)
- 1 piece of wire (guitar/banjo string would be ideal, if you don't have that you can strip a small length of washing line, they usually have a good width wire inside the plastic core)
- 1 piece of very hard wire, or a nail, bent into a figure of 8. or a washer with a hole or a small L-bracket would suffice. as long as it can fit onto your long bolt. (i'll explain more in step 6)
- 1 small piece of scrap wood to act as a bridge
Red/black to either pin, it makes no difference.
You have now made the easiest contact mic set-up you're likely to find anywhere.
Cut out the hole and insert/screw tight the chassis socket.
Head back inside the box and tape the piezo disc onto the surface of the box you want to be your front.
this is where we will thread our wire into laters.
One at the bottom end, close to the edge. This one is best done at an angle with the hole going from the bottom of the stick to the side. (go peek at step 6 to see why)
And also 3 at the top end of your stick, with the middle hole large enough to fit your long bolt.
insert your bolt into the middle hole, with the long shaft of it at the back end of your instrument (look at first step if i've not explained it proper)
now put both nuts onto the bolt all the way to stick, also place your bent nail/washer with hole/figure of 8 bit of wire (again, i'll explain in a step or two)
MAKE SURE to not drill into the piezo disc at this point. That would be bad.
First tie your wire to the base, loop it around the holes in your stick and the corner of the box as shown.
To tie it at the top end, you're going to first thread it through the small hole underneath the bolt, then thread it through the bent nail/washer with hole/whatever you have, then thread it back through the stick through the top hole and pull it tight before anchoring it to the head of the bolt.
the reason for the bent nail/washer with a hole thingy is thus: when you 'unscrew' the second nut, it will push the wire further away from the stick and increase the tension in the wire and therefore change the pitch. with a bit of careful tweaking you should be able to tune it to whatever note you desire! This, in my opinion, is the easiest and most effective way of making a homemade cheap as chips tuner. I've not seen it used anywhere else but I'm sure I won't be the first person to have used this method.
Step 7: Fin
I didn't put any thought into making this build pretty, as it was more of a prototype for the different way of tuning a string. You can obviously decorate the box in any way you desire, and can substitute what you use for the resonator and the neck and the wire with a plethora of other materials to make a wide variety of different sounding instruments!
Once plugged in you can tap the sides as a percussive Cajon, or use the string with a slide to play like a diddley bow!