27 replies to this topic

[psupine]

I know this is an old thread, but I just wanted to add an observation that seems to be missing.

Even if you have some clever differential pressure measurement against a ground station reference, what if you want to land somewhere other than directly in front of you, and you don't have an expected pressure reference at that landing site?

At some stage, you'll need some means of measuring distance, be it ultrasonics or IR. Personally I'm all for sonar.

I also don't see the single head (combined Tx/Rx) minimum distance being a problem. By the time you are within 6 inches of the ground, the landing can be a pre-canned motor shutdown sequence. If having a combination Tx/Rx saves weight that has to be a good thing.

[dankers]

There is a sonar module already being worked on by a developer called Sambas, not sure if he has a test flight yet but it must be close.

[osnwt]

dankers, on 18 July 2011 - 01:02 AM, said:

There is a sonar module already being worked on by a developer called Sambas, not sure if he has a test flight yet but it must be close.

The sonar works for OP for a long time, and recently was ported to the CC using 2 PWM inputs for connection.

Tasks to be done:
- provide a dynamic hardware configuration to allocate inputs to sonar instead of servos (we just started adding such dynamic configs where possible).
- no altitude hold was tried yet. I thought it is quite easy, but it needs to be done.

Partially, I believe this waits for dynamic module start/stop framework, so optional modules can be started based on the run-time configuration, not a compile-time.

[joecnc2006]

Great, I have a module waiting for it..

[michel pet]

I have also a module waiting for it gread news.

[mnuapel]

will there be one or two pressure sensors on the openpilot board? Will we be able to measure airspeed?

[BrokenRotor]

I have a Compass (5883L), Baro and Sonar available for testing here, as well as a NEMA GPS.

[dankers]

mnuapel, on 31 August 2011 - 10:58 PM, said:

will there be one or two pressure sensors on the openpilot board? Will we be able to measure airspeed?

Its an external I2C device.