hi, i got a new proyect going on.. im just starting, and i need an altimeter i'll build something like an helicopter but i need to know at what altitude is it to do something (ie. descend) some one knows how can i do that?
Depends on what altitude you want to measure. The ones based on air pressure are not accurate enough for a few feet. An ultrasonic tape measure (http://www.nwbuildnet.com/stores/bm/calc/3312.html) pointing down could do a better job for the first 50 feet of altitude and will be cheaper. Of course you have to mod it to get your control signals and shed some weight. For real close ground work this may help http://www.pololu.com/products/misc/0136/ . There are also accelerometer/gyro based systems around that calculate position relative to starting point based on acceleration and orientation, but as far as I know those are all very expensive. If your radius of action is small enough you could try tracking with a ground bound system. Your helicopter would only have to carry a cats eye reflector, so ground bound lasers (3 for triangulation) are able to track it. Electronics will be reasonably simple, but software will be a major task.
Has anyone tried to chop up one of these ulatrsonic measuring tapes for a good logic output? That would have some usefull applications in amateur robotics.
