Motion switch, need suggestions

[Andres Rodriguez]

I am planing to make a wand type POV sign. I would like to use a motion switch on the wand that will cause an interrupt (either high or low on an input pin). I would appreciate suggestions about the type of switches and sources.
I recently made a rotating POV sign with a 28X chip. The sign is rotated with an old RC car motor and the letters start forming when an interrupt occurs (using an IR sensor to cause the interupt).

 

[slurp]

Are you trying to detect the direction the wand is being waved or if the wand is moving in general?

regards,
colin

 

[Andres Rodriguez]

Moving in general will work in this case.

 

[slurp]

Have you considered tilt sensors orientated to give an open contact when waved in one direction and closed in the other?

I guess the complex solution might involve an accelerometer!

regards,
Colin

 

[Andres Rodriguez]

I have an accelerometer but it would be an overkill for this application. A tilt sensor will do fine. Can you suggest a manufacturer and/or supplier?
Thank you for helping
Andres Rodriguez

 

[MFB]

A tri-axis accelerometer (eg.MMA7261QT) would be your best bet for this type of application and they are pretty cheap these days.

 

[boriz]

Or a piece of springy wire passing through a little hoop. A bit of Ernie Ball standard 0.013 gauge electric guitar string works for me. I used it ‘coz I just happened to have some to hand, but I’m sure anything similar will work.

 

[hippy]

A commercial refinement on Boriz's suggestion is used in those balls which flash LED's as you bounce them - A very weak and flexble spring with a weight on one end, the other end connected to the PCB, the contact is a pin running up the centre of the spring.

 

[MFB]

DIY

I bet some of you even like rolling your own capacitors using baking foil and greaseproof paper!

 

[Andrew Cowan]

I like hippy's idea - I believe this is how some vibration sensors work.

A

 

[BrendanP]

Parallax do accelerometers mounted on small 100thou pin break out boards that are easy to interface with picaxe.

 

[eclectic]

@Andres

One of these perhaps?

http://www.rapidonline.com/Electronic-Components/Sensors/Tilt-Tip-Switches/Non-mercury-vibration-sensors/72379/kw/78-0769

Reading the datasheet for the above, it appears that they're “Comus”

This also might help:
http://www.comus-intl.com/comus-vibration.asp


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[gengis]

I bet some of you even like rolling your own capacitors using baking foil and greaseproof paper!

Of course. How do you do it?

Keep 3/32" window glass, and sheet polypropylene on stock. Wax paper is iffy.
Aluminum foil for the small stuff and aluminum sheathing for serious high current, HV caps.

 

[Andres Rodriguez]

First, I want to thank everyone for their suggestions.
Second, I tried Hippy's idea and it works great.
Third, MFB, I have not rolled any capacitors during the last 3 months but now that you remainded me I will start tomorow.