e-heli
Heliman
Location: Kentfield, CA
| When Futaba came out with their GY501 with non-piezo gyro technology (their Silicon Micro Machine technology), I was hooked. Last year I finally got rid of all my piezo gyros and haven't looked back.
One of my other hobbies is electronics. I had worked on a piezo gyro a while back, so I had access to the sensors used in these gyros. These sensors were originally designed for use in video cameras for image stabilization systems. Typically there is one sensor used for left/right and another used for up/down stabilization.
The sensor contains a triangular steel beam that has one piezo element on one side used to cause the beam to vibrate. There are two additional piezo elements on the remaining two sides of the triangular beam that sense the amount of rotation. By comparing the phases of the two signals of the sense piezo elements against the drive piezo element, one can compute the angular velocity.
Now here is the scary part. I took one of these sensors apart and here is what I found:
http://home.attbi.com/~anilpatel/heli/Piezo-1.jpg
http://home.attbi.com/~anilpatel/heli/Piezo-3.jpg
Sorry for the slightly fuzzy pictures. My digicam didn't do macro pictures well.
Notice how the beam is suspended by two tiny wires. The whole assembly looks terribly fragile. I can easily see how this sensor could be damaged in a crash. The assembly reminds me of the inside of a receiver crystal. Ever opened one of those?
I personally don't ever want to fly piezo again. S.M.M. sensors look more robust to me. For more info on the S.M.M. sensors, go to the manufacturer site:
http://www.siliconsensing.com
Hope this was informative.
--Anil |
