[ggrif]

Hello all. I'm building a 650+ heavy lift experiment and am curious if there are any options out there for radar and/or sonar for RC craft. Or LIDAR. Also, a way to control 2 camera gimbals, one on the front another on the rear. And maybe two more gimbals, left and right. 

Thanks

[TheOtherCliff]

I suggest reading this sonar thread with the understanding that you should not use the HC-SR04, but probably the Maxbotix 1240.
https://forum.librepilot.org/index.php?topic=3390.0

For more channels use something like SBus, DSM, or even PPM to get around the 6 channel FC PWM input limitation.  I hear that many professional rigs use two transmitters and two receivers, one set for the pilot and one for the photographer.

Part of your problem is that you will want to control 2 or 3 rotation directions (requiring 2 or 3 transmitter knobs) on each gimbal, and PWM going into the gimbal.  Converting a lot of channels from a "one wire" (SBus, DSM, PPM, etc.) receiver connection to individual PWMs can be a challenge.  Assuming a single RC radio with enough channels to do what you want and a protocol (e.g. SBus, DSM, etc.) that can read all the channels in LP firmware, there are for instance, SBus to PWM and PPM to PWM (etc.) converters available.

But the best way might be to retask one or more old CC3Ds ($10 shipped on eBay) to turn them into WhateverProtocol to PWM converters.  Connect it to the same stream as the main FC and set it up to to select a set of channels from the input stream and output those channels on the 6 ESC servo connectors (and other places (Flexi-IO?) too).

Look into CourseLock flight mode.

[ggrif]

Thanks for all the advice Cliff, much appreciated. I'll get to work now.

[octavvian]

Hello, can this project be done on LP and REVO FC?

%https://youtu.be/kmpxkKq3zNA%

%https://github.com/Shaofuhw/UltrasonicMavlink%

[TheOtherCliff]

Yes.  It only needs someone to code it and champion it.

Be aware though that cheap sonar sensors (HC-SR04/05) do not work if there is prop/motor noise.  It probably requires the MaxBotix 1240 sensor which is about $45 each, so that would be $225 worth of sensors.  Also the HC-SR04 / 1240 use a port for each sensor.  You would need to use a version of sensor where 5 can be multiplexed and individually addressed from one port.

[Mateusz]

• For altitude hold you need narrow strong beam that is not disturbed by props to get accurate altitude estimate
• For obstacle avoidance anything that stands out from props noise would be good enough I guess
• MaxBotix sells sensors which have different beam patterns as well as I2C bus sensors. So you could get sensor with I2C bus and connect as many sensors to one port as needed.

In the attached movie project the guy covers only front, back, right and left, if these sensors they use have narrow beam they won't cover diagonal directions well. That's why in demo they push board on the copter from the sides and not diagonal directions.
Also wide beam won't be very robust against prop noise. Better than ultrasonic sensor would be some sort of laser or IR sensor/Camera.

I am pretty sure such a project is possible, but seeing that movie I doubt they have a good results that are practical, it's probably more fun to play.

[octavvian]

Thanks for replies.

[ggrif]

Thanks again. I'll continue to noodle and root around on this, appreciate the tips