Looking for a (tilt?) sensor.

W9GFO

I'm searching for a very cheap and small sensor to use in a POV wand. The idea is to sense the abrupt change in direction when you wave the wand back and forth. I found a couple inclinometers but reading the data sheets, I don't think they would like operation above 10 hz.

A SPDT reed switch that has both poles normally open might work but I can't find such a thing.

What should I be looking for?

Rich H

Mike2545

If you just want to detect movement then something like this might work:

www.goldmine-elec-products.com/prodinfo.asp?number=G16881

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Mike2545

This message sent to you on 100% recycled electrons.

W9GFO

That's close. The problem I see with that one is that it can't tell which way it is tilted, only if it is tilted.

Rich H

Franklin

An accelerometer is probably what you will need.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen

W9GFO

Franklin said...
An accelerometer is probably what you will need.

Maybe so. They aren't that expensive, I was hoping for something under a buck and not quite as fancy.

Rich H

edit: found a freescale 3 axis accelerometer with an SPI interface for $2!

Post Edited (W9GFO) : 8/3/2009 12:13:00 AM GMT

Carl Hayes

Why not use a small weight on the end of a small straight spring, and contacts surrounding it? Make the spring from something like a safety pin (straightened out), mount one end solidly, and ground it. Put a weight (fishing sinker) on the free end. Put contacts (perhaps made from, for example, other safety pins) around the free, weighted end of the spring, separated by a small distance that determines the sensitivity. When it's not waving about, the spring is not deflected and none of the surrounding contacts are grounded. When you wave it about, the spring gets deflected because of the weight on the end, and hits one of the contacts, grounding it.

This has the disadvantage, for these forums anyway, of being simple, reliable, and inexpensive. Such properties almost disqualify it here. But you can overcome that by, perhaps, gold-plating everything.

Of course, if you're determinedly resolved to enrich the manufacturers of accelerometers and associated circuitry, you can simply order their products and have them delivered straight to the landfill, saving time and effort.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
· -- Carl, nn5i@arrl.net

Post Edited (Carl Hayes) : 8/3/2009 10:50:24 PM GMT

W9GFO

Carl Hayes said...
Why not use a small weight on the end of a small straight spring, and contacts surrounding it?

That is essentially what I was looking for, but in a component form.

Carl Hayes said...
This has the disadvantage, for these forums anyway, of being simple, reliable, and inexpensive. Such properties almost disqualify it here. But you can overcome that by, perhaps, gold-plating everything.

Of course, if you're determinedly resolved to enrich the manufacturers of accelerometers and associated circuitry, you can simply order their products and have them delivered straight to the landfill, saving time and effort.

So $2 accelerometers deserve to go to the landfill but disfigured paperclips safety pins and repurposed fishing weights don't?

What if I gold plate the accelerometer?

Rich H

Post Edited (W9GFO) : 8/4/2009 11:44:12 PM GMT

Whit

You might find a damaged Wii controller at a yard sale or thrift shop.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Whit+


"We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney

Carl Hayes

W9GFO said...

Carl Hayes said...
Why not use a small weight on the end of a small straight spring, and contacts surrounding it?

That is essentially what I was looking for, but in a component form.

Carl Hayes said...
This has the disadvantage, for these forums anyway, of being simple, reliable, and inexpensive. Such properties almost disqualify it here. But you can overcome that by, perhaps, gold-plating everything.

Of course, if you're determinedly resolved to enrich the manufacturers of accelerometers and associated circuitry, you can simply order their products and have them delivered straight to the landfill, saving time and effort.

So $2 accelerometers deserve to go to the landfill but disfigured paperclips and repurposed fishing weights don't?

What if I gold plate the accelerometer?

Rich H

No, not at all.· But when you want only to sense the existence, rather than to measure·the magnitude, of an acceleration, a safety pin and fishing weight are considerably cheaper.· And who said anything about paper clips?· Not I.· Paper clips are made from steel that's inferior to that in safety pins.

My point was that those who insist on doing everything in the most expensive possible way might still want to spend for an accelerometer -- let's not forget the associated circuitry, which is not free -- and these people can still use the inexpensive solution but might find their houses cluttered with unemployed accelerometers and circuitry to run them.· The landfill is a solution to that.

Of course,· instead of buying accelerometers they could instead send the money to the landfill directly.· This would have the same ultimate effect as actually using an accelerometer where it isn't needed.

Alas, the spirit of homebrew has atrophied, and the safety-pin industry must languish in desuetude, or else fall back upon dry cleaners, and·parents of toddlers, to provide a market.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
· -- Carl, nn5i@arrl.net

W9GFO

Funny, I was thinking safety pins but wrote paper clips...

Rich H

Carl Hayes

Not as bad as me, though. I've got to proofread everything I write, or I'll write of paper pins and safety clips --

73 OM

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
· -- Carl, nn5i@arrl.net