Radical Magnetic Sliding Volume Control

[Stocker]

I have been listing for sale lately a lot of this sort of thing at work and I have had an idea. These are basically switches, activated by a magnet passing in close proximity.

Volume control: slide the knob or whatever up or down or alternatively left/right to change the volume, across the width/height of the amplifier. A magnet on the back of the operator actuates the magnetic switches.

These particular switches seem ill-suited for the task. If some could be found that have low resistance, it would be a pretty neat volume control.

[cliffforrest]

Do a search on REED Switches.

A bare switch has very low contact resistance. The one you have found includes 3 metres (!) of wire in the test spec.

[I_Forgot]

You can buy the raw reeds in glass tubes very cheaply at many surplus electronics dealers (maybe 10 cents each). I don't think it would be hard to mount a bunch of them on a rotary switch frame, then remove the switch's wiper and replace it with a small magnet, or arrange them in a linear pattern with a magnet on a slide nearby.

I say do it. I can think of all sorts of nifty Rube Goldberg type contraptions that could be used to move the magnet past the switches. It should be a lot of fun.

Don't let the nutz who claim that magnets and magnetic materials near and in the signal path will degrade the sound stop you.

I_F

[Stocker]

Cliff, by this type of thing, I meant auto switches for pneumatic cylinders. Some are reed, some are hall effect solid state. This was the first one I could think to remember where the datasheet was. The 3m wire by the way, could be trimmed.

I_Forgot: The concept was what I was trying to get across. We are too proud of our industrial automation stuff for it to be affordable for me to tinker with. ($). The linear array/slide was what I was getting at, but it is pretty clever of you to think of a rotary array.

I have many, many other projects in line before I even start considering using this for anything for myself. I wanted to present the concept for you guys to consider and play with if you were so inclined.

As for the folks concerned with the magnets in the vicinity of the signal path, to them I say I will likely be equipping my amplifier with an IEC standard power jack and using a *gasp* free power cord of the <$5 variety, so you might guess my position on the hazards of these (tiny, fixed) magnetic fields in the area. Let's not mention the overwhelming magnetic fields from power transformers, overhead lights etc. shall we? Oops, guess I did.