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Berlin
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Hi everyone,
I´m working on an project  were I have a cube which has an mini ardunio inside and somekind of sensor, which checks if the cube is turned.

So i searching von an "rotationsensor" or some other senor which works with the ardunio.

Maybe some has an good idear!

Thx Timme
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Hi Timme,

How about a mercury tilt switch ( like in http://www.technologystudent.com/elec1/switch4.htm ) or equivalent ?

If you strategically place a number of them in the cube (in the corners for example) then it should be pretty easy to detect the cube rotation.

Best regards,
Lionel.
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an electronic compass would do the job but costs about 40 euro:
http://www.roboter-teile.de/Shop/themes/kategorie/detail.php?artikelid=11&source=2
http://www.roboter-teile.de/datasheets/cmps03.pdf
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Daniel
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Quote

How about a mercury tilt switch ( like in http://www.technologystudent.com/elec1/switch4.htm ) or equivalent ?

I used to use these all the time too... They are terrific for sensing movement.

I stopped using them when I found out what a serious environmental hazard they are: even small amounts of mercury released into the natural environment end up accumulating in living things-- so the higher up the food chain, the higher the potential concentration of mercury. Ultimately it means you end up eating it, and risking the potential hazards of doing so. Not good if you like fish.

Anyway, buying mercury switches means supporting the factories that make them, which isn't really necessary when there are lots of alternatives. There are ROHS equivalent devices, David C. knows where to get them in Europe.

http://leahy.senate.gov/issues/environment/mercury/index.html
http://www.epa.gov/waterscience/fishadvice/advice.html
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> I stopped using them when I found out what a serious environmental hazard they are

You need to put things into perspective. If you reuse these switches and properly discard them at the end of their life there is nothing wrong with them. The amount of Hg that humans have already spread in the environment and continue to spread is enormous. You contribute to that simply by being alive and using industrial products.
If you are totally against using Hg then you cannot use fluorescent tube lamps either. What do you do with them once they cease to work? Properly dispose of them, or do you simply throw them into your regular household trash? What if you break a few of them (or even a Hg filled thermometer) inside your house? Do you evacuate the building and move out?

Anyway, I'd consider using a three axis accelerometer.
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Daniel
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Quote
You need to put things into perspective. If you reuse these switches and properly discard them at the end of their life there is nothing wrong with them.

When ROHS alternatives exist, then why not use them instead?

Quote
The amount of Hg that humans have already spread in the environment and continue to spread is enormous. You contribute to that simply by being alive and using industrial products.

I know the situation seems bleak, but in saying this you are discounting the environmental hazard, and also the idea that people have some volition to change the situation. Sure, the world is already screwed, so why not buy some more  mercury smiley

The fact is that there is a significant amount of mercury in a mercury switch (I just looked this up, and there is about 50-80 times as much mercury in one automotive trunk mercury swich as there is in a fluorescent light bulb), and it concentrates in fish.

So hey, why not use something that is less harmful?

 
« Last Edit: January 04, 2007, 03:35:56 pm by Daniel » Logged

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You can get mercury free tilt switches. They have a little rolling ball inside them. I assume this is how the RHOS ones work too.

http://www.dse.com.au/cgi-bin/dse.storefront/459d645604fcb9ac2740c0a87f9c0757/Product/View/P7863



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Daniel
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In North America Mouser seems to be the cheapest supplier for mercury-free tilt switches, with some models at about $1.25 each.

The Electronic Goldmine has them for $1 US each, new-old-stock.

Digikey also has about ten different mercury-free tilt switches, mostly $5-10 each:

Assemtech in the UK has a page describing about 25 different non-mercury tilt switches that they make, with links to their distriibutors.

This Assemtech ROHS compatible switch seems to be the popular on in the UK: the CW-1300-1, at about 1 Euro each. Looks like this:
« Last Edit: January 04, 2007, 11:15:49 pm by Daniel » Logged

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You can also build them yourself. A wooden base with a small hole in it, a steel ball (with a considerably bigger diameter than the hole) and two wires/nails arranged in an X shaped "dome" surrounding the ball.  
 
When undisturbed the ball rests on top of the hole, not touching the wires. When you tilt this thing the ball will roll against the wires and make contact between them.
Don't have a picture of this contraption, I hope the explanation made sense.
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