Here's all you need to build the Pressure-in-a-tube foot wah

[Skidood]

Please let me know if you build this.
Pics of the project are forthcoming.

Andy

PS..The problem I reported in my last post has been resolved in this build.

//www.saa-online.ca/text.htm

//www.saa-online.ca/tube.htm

[aron]

Thank you. I can think of a few other things I can use this pressure sensor for.

[brett]

Hi.
Has anybody else tried Hall effect sensors?  I built a wah with one.  A magnet stuck under the pedal and the sensor in the base.  Worked 100% good.  I did look at pressure sensors once, but they seemed kinda expensive.
cheers

PS the idea came from work, where the mad scientists do some very sensitive weighing.  One thing is to weight a big drum of soil and grass or crop.  A small magnet is stuck to the bottom of the drum, which is on springs, and the sensor is a UGN??? magenetic field (Hall effect) sensor on a concrete pad below.  The more weight, the more the springs get squished, the stronger the magnetic field at the sensor and the more voltage it passes.  Magnet plus sensor costs $5 and can detect about 0.001mm (1/25000th inch) height change or 0.01g weight change in a 500kg drum.  Neat, huh.

[Paul Perry (Frostwave)]

When I was a child (!) I had a rubber bulb operated swimming frog, you squeezed the bulb & this increased the turgidity of the hollow legs, straightening them out & giving a kick effect.
I suppose you could make a low cost led/ldr unit on this principle.