How do i build or where can I find an interactive capacitive proximity sensor?

I am building an electronic version of an old Brazillian instrument called a Berimbau. Part of it is played by moving the cabaca or gourd closer to or further from your body. This movement bends the pitch or mutes the output. I'm attempting to replicate this effect with a proximity sensor that will do the same job as I move the instrument back and forth from my body. My problem is all the sensors i find are just on off switches. I need something that will increase gradually with the distance. So if anyone out there has a solution then do please help! On a note tho there is a device available for guitar called a wah probe. It is exactly what im attempting to build but costs in excess of £300 so when the first thing i will be doing is dismantling it and hacking up the copper plate i dont see the point in wasting the money! Especially when it will probably take several attempts to get right...

Kiteman7 years ago
"Stud detectors" sometimes have a some-what analogue output, lighting up a series of LEDs as they get closer, or putting out a changing tone.

There's an instructable for making a door-bell out of a stud-finder, but I can't find it now...


jeff-o7 years ago
There's an instructable here that documents a 3D position sensor based on capacitive sensing.  As an object withing the sensor field moves, the capacitance changes, and this changes the RC time constant.  This change is detected by a microcontroller.

Perhaps something like this could be adapted to your use?

The alternative solution is to use an IR range sensor.  They are available with either analog or digital PWM outputs.  Again, the output varies depending on the distance between the sensor and the object.
Hmm, People like Atmel/ Qprox and Analog devices supply silicon to do what you want directly.

Like Nacho says though, the classic theramin is "body sensing" , so you could use that to give you an audio signal that can be onward processed.

Steve
NachoMahma7 years ago
.  Anything like a theremin?