wanting to make a prototype
Chaslie
Posts: 7
Hi,
I have a limited knowledge of electronics and need·assistance on a project that I am trying to do.
I am wanting to make a prototype of what I think should be a fairly simple device that will play a short audio clip (less than 1 sec) when activated by motion.· In this case, I am referring to·when the device itself·is·moved and not·to a motion sensor that detects another object's motion.
More specifically, I·want·the device to trigger a short·audio clip (like a door slam or a gun firing, for example)·when it reaches a certain magnitude of acceleration, inertia, or perhaps velocity.· I also want·it to·be able·to·reset and trigger·the audio clip again in under one second so that it can replay the audio clip·repeatedly if it experiences·a vibration or oscillation of sufficient magnitude.
In order to accomplish this, what all do I need?··Would an accelerometer or some other kind of inertia switch work? ·Also, is there anyone out there who·engineers schematic designs·for prototypes?··I would appreciate any help.· Thanks,
Chuck
Post Edited By Moderator (Joshua Donelson (Parallax)) : 10/23/2009 4:30:37 AM GMT
Comments
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Post Edited (Paul Baker) : 2/10/2005 8:10:31 PM GMT
Chuck
·
Post Edited (Paul Baker) : 2/10/2005 10:03:54 PM GMT
The Memsic is a nice sensor...but Analog Devices sells them too.· The ADXL202 is a 2g one and the ADXL210 is a 10g one.· I believe they have a 50g one too!
I've played with the 210 and it has a pulse width that's representative of the g you're at.· so, with no motion and sitting level, it's pulse width is 50% of what you set it to (can't remember the minimum option--might be 2uS).· Anyhow, the higher the g the higher the duty cycle and vice versa.
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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
Post Edited (Paul Baker) : 2/10/2005 10:18:19 PM GMT
Also, (this is to Steve) when you mentioned using an opto were you refering to a motion sensor?
He himself sat in the rocket sled and sped off at whatever speed.· Well, I guess when he hit the water (you usually see it spray up like a log ride) he hit 15G's.
He survived, but detached both retina's.· At least that's all the damage I remember.
In Canada, our air guys wear G-suits to stop the blood from pooling in the torso.· The US has just come in to using them in the last bunch of years.
They would just 'grunt' to keep from blacking out.
Chaslie: What I'm refering to as an opto is simply a light source (IR or visible) and a light detector.
They do sell them in a package where they face each other and are separated by a cm or 2.· The device just needs something to split the beem.· Usually a small blade of somesort to break the light beam and it changes state.·
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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
You may also want to capture situations where an object exceeds a velocity without reaching a 2 g acceleration, like if you were on a swing and threw the object forward at the low point of the swing arc, the acceleration due to the swing may not be over 2 g the throw may not be over 2 g but the resultant velocity is greater than your threshold.
One thing to consider is the sensor above is a 2D sensor, it will not detect acceleration in the direction vertical to the sensor. If you cannot gaurentee the object will accelerate in one of the two axis, you'll need a 3D accelerometer. To get the total acceleration of the two axis would be a = sqrt(ax^2 + ay^2), for 3 axis a = sqrt(ax^2 + ay^2 +ax^2).
Steve: ick, my gma had her retinas detach but not through such spectacular means. Its estimated that Princess Di experienced 100-150 G causing the aorta to detach from her heart.
Post Edited (Paul Baker) : 2/10/2005 11:47:46 PM GMT
Paul
Re: detaching aorta.
Same thing happened to Eval Kneival when he tried to jump the fountains at Caesars.·
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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
REFRENCE YOUR COMMENT ABOUT THE "SLOTTED OPTICAL SWITCH" ABOVE. THERE IS ANOTHER WHICH HAS VERY GOOD UTILIZATION BUT NOT KNOWN AS WELL SINCE MAG TAPE IS NOT THE TOP DOG IN STORAGE ANY MORE. IT IS THE REFLECTIVE OPTICAL SWITCH.
http://www.fairchildsemi.com/ds/QR/QRB1113.pdf
THIS IS JUST ONE TYPE AVAILABLE. IT CONDUCTS WHEN THE BEAM IS REFLECTED BACK WITH THE BEAM PATH IN THE SHAPE OF A "V".
SPENCE
K4KEP
Here's a supplier up here in Canuck-land http://www.hvwtech.com/pages/products_view.asp?ProductID=377
He's got some nice goodies on there.
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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
use a piece of silver paper like off of a pack of cigarettes and glue on the dot to be detected. We used to use clear tape to hold a piece of foil on tape when we could not get the foil with adhesive already on it. Rubber cement a dot of foil to your mark is another way.
73
spence
k4kep