where can I get one? ----- Original Message ----- From: "Russell McMahon" To: Sent: Monday, November 18, 2002 5:18 AM Subject: [EE]: Electronic gyros Fw: [AR] Gyro Hunters Claimed to be useful gyro building blocks (see discussion below) http://www.spp.co.jp/sssj/sirikon-e.html Certainly look "fun" for experimental use. But also see John Carmack's comments at end - and he has hands on practical experience (including manned rocket only supported flight, *so far* for less time than the Wright Brothers first flight). RM _____________________ ----- Original Message ----- From: Scott Bowers To: AROCKET@HOME.EASE.LSOFT.COM Sent: Sunday, November 17, 2002 2:45 PM Subject: Re: [AR] Gyro Hunters I am not really the electronics guru. I have a friend in the aerospace industry who pointed them out to me. The price was approx. 37.00 dollars each, and you need three. John made a gyro unit for his rc helicopter. He designed the board and firmware himself. He put the thing upside down and locks it in and it stays there, pretty impressive. He will eventually be manufacturing some. He said they have a sample rate of about 90 times per second, and should be fast enough with the right servos to steer a rocket. We worked out an idea for X, Y, and rotational axis control using only two servos and a link similar to what they use in tailless planes. Been one of my goals to do this, may actually get around to it someday. Scott ----- Original Message ----- From: Brian Feeney To: Scott Bowers ; AROCKET@HOME.EASE.LSOFT.COM Sent: Saturday, November 16, 2002 5:20 PM Subject: RE: [AR] Gyro Hunters In a write up on their site they compare the different technologies employed in gyros. They claim to have solved the problem of external vibration normally causing the Vibration style to be ineffective. Have you flown this and or know of its use on rockets aka was it really effective in the context of the vibration from the rocket. How much were you paying for them? Cheers, Brian The da Vinci Project bfeeney@davinciproject.com http://www.davinciproject.com -----Original Message----- Scott Bowers wrote Sent: Saturday, November 16, 2002 7:47 PM I would use this one. Smal, fast, And cheap. http://www.spp.co.jp/sssj/sirikon-e.html Scott T Bowers ____________ At 07:45 PM 11/16/2002 -0500, you wrote: I've seen them fly and they are an interesting toy. There are several problems with the simple stability platform. They use solid state rate gyros and no accelerometers. The Dragonflyer does not hover without a lot of manual control. It rocks from side to side in flight due to the low resolution of the rate gyros. You must constantly correct for drift. If they added a three axis accelerometer then it would be a stable platform that would hover. It would be questionable as an active guidance system for a rocket. John Krell A three axis accelerometer doesn't have anything to do with attitude stability, and can't help sub-par gyros. Accelerometers are only needed (in conjunction with the gyros) for position, and it takes really surprisingly good gyros and accelerometers to make a 6DOF inertial integration not fly out of the room in seconds. 2D inertial with a single gyro and dual axis accelerometer is not that bad for human-scale movement, but as soon as you add the third dimension with the constant 1G gravity vector, the integration gets ugly real fast. A hovering vehicle done strictly with integrated inertial sensors (no absolute sensors like GPS, horizon, sun , electrostatic, magnetometers, barometeric, laser, etc) needs a much better set of sensors than the $9,000 Crossbow IMU we use. After a 15 second flight, the inertial position is already several feet off, and diverging with a velocity. It is good enough for things like apogee detection, but definitely not for the "hover steadily in front of me" maneuver. John Carmack -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads