Hello Robert, Nate & PIC.ers, > >Date: Fri, 25 Jul 2003 10:31:34 -0600 >From: Robert Ussery >Subject: Re: [OT]: Dynamic tilt angle sensor > >Thanks, Nate! > As I said, I'm aware of the uselessness of a static tilt sensor in an >aircraft, since it will only function as a turn coordination indicator. I >was just wondering if there was some other solution, i.e., el-cheapo >gyroscopes, etc. >Fortunately, gyro or accelerometer drift shouldn't be an issue, since I'll >be able to periodically re-center it by flying straight on a heading for a > A long time ago (20+ yrs) I was also involved in the research side of a UAV project. It was my mission to dig up whatever material I could on guidance techniques, magnetometry, etc, etc. I've just had a quick grovel & can't find the report, but a description will do for now. Some privateers at NASA had built themselves a *turn rate* sensor using, of all things, an air stream generated by a very low flow (laminar region) jerry rigged fan. It was a *low* flow, as in your-breath-is-too-much. The stream was directed at a PTC thermistor (or pair, I think?) and these were kept at a `constant-ish' temperature by way of their resistance characteristic (cheap control-loop that). If the stream deviated from straight, then one PTC would be force-cooled more than the other & it would automatically start drawing more current to maintain it's temperature. The currents in the PTC were then monitored to find the rate-of-rotation of the device around the axis, I think they used a Wheatstone bridge with the two PTCs in diagonally opposite corners to give a directly readable voltage o/p. It was meant to be used as a yaw-rate sensor, much as the traditional panel gyro turn-rate indicator, but which had a transmittable output & could be used for a simple wing-leveller controller. Could a 3-axis version give you what you're looking for? bestos, John eMail from the desk of John Sanderson. JS Controls, PO Box 1887, Boksburg 1460, Rep. of S. Africa. Tel / Voice / Fax : 27 11 893 4154 Cell : 082 741 6275 email : john@jscontrols.co.za Web http://www.jscontrols.co.za Manufacturer & Purveyor of laboratory force testing apparatus and related products & services. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads