RE: [Paparazzi-devel] reply to:distance measurement for landing.(gisela.noci)

[gisela.noci]

Hi Chris.

I have not tried the senscomp product. This is basically the 'old' Olympus (
I think) camera ranging device, originally made by Olympus, now discontinued
and taken over by Senscomp. The transducer is not a Piezo element, but an
electrostatic membrane, which has a 200v plus DC bias on it, and then is
excited by a 200v Peak to Peak pulse train. This has a reasonable chance of
success I believe. What is desirable is however its beam width, which is
greater than the smaller 40Khz Piezo transducers. I am not sure how well it
will work at close range though - less than a meter? The transducer rings
considerably which creates a close in dead zone. Good luck with it.

Joe

-----Original Message-----
From: address@hidden
[mailto:address@hidden
] On Behalf Of Chris
Sent: Sunday, November 22, 2009 1:41 PM
To: address@hidden
Subject: [Paparazzi-devel] reply to:distance measurement for
landing.(gisela.noci)

Hi.
This is what i have done also.
I descend in to the wind with 5 degrees down attitude which translates 
to about 2m/s and when/if the ultrasonic range finder finds out that we 
are within the sonar's range AND the readings are good enough AND the 
sonar is enabled from the flight plan THEN the flight plan reduces the 
descent rate to 1m/s and below 1m it holds a level attitude with the 
throttle cut.
Only testing will show if the sonar is up to the job.
I will also try the Senscomp's sensor with uses 12W of power and its 
range is up to 10m according to the Senscomp site.
http://www.active-robots.com/products/sensors/sensors-senscomp.shtml
The Senscomp site says that it uses 2A at 6v during transmit and the 
transducer works with 400V !!!
What do you think about it, any experience?
Chris



_______________________________________________
Paparazzi-devel mailing list
address@hidden
http://lists.nongnu.org/mailman/listinfo/paparazzi-devel