Posts

Jetson Nano and AI / Vision

  It would be nice if a solar drone could detect ships for boarder patrol, people in the water for rescue, and clouds for maximizing solar collected by the plane.  It could then plan a route to get closer pictures of ships or people and avoid clouds.  This paper on ship detection also compares Jetson Nano to Raspberry Pi and shows that Jetson gets more processing per watt.   We have thought this too and have been playing some with Jetson Nano.   In ArduPilot a Jetson Nano can be the companion computer for both 4G cell data and for image processing/AI stuff.  It can run at 5 watts and is about 135 grams.      We are collecting links to work on some of the vision problems that we are interested in below.   Boat or Ship Detection       There is plenty of work on using computer vision to detect ships.   Cloud Mapping        We would like to know where the clouds are and where the blue sky is so that we can navigate a path with plenty of solar power.   Searching for "cloud" gets

S800 Group Build, Project Rosetta Stone

    This seems a great source for learning iNav:   S800 Group Build, Project Rosetta Stone    

Cellular Data Connection

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 If we can use cellular data to connect to the airplane then it could go really far and we could stay connected. 4gUAV Peter J Burke connected 4G to an airplane and wrote about it .  He also wrote some later papers with projects using 4G .  So far we are just looking at how to do it but will probably do this at some point.   The first thing is a USB to 4G adapter like:     Next a very tiny Raspberry Pi Zero W : Then it seems ArduPilot is needed.  It runs on the flight controller but talks with the Raspberry Pi as a companion computer .   The 4G modem plugs into the Raspberry Pi.   Peter has setup a 4gUAV gitlab repository that is really the place to go.  Here is a video where Peter flies a plane just from over cellular. UAVPAL Disco4G   Also interesting is  UAVPAL Disco4G .  This uses a drone that can operate over wifi and puts a cell hotspot/wifi on it.  This has latency issues for control.   Over a cell network it is probably more reasonable to be sending GPS waypoints and not tryi

Facebook group Solar RC Airplanes

  I created a Facebook group called Solar RC Airplanes .  I am hoping to find other people interested in this topic.   If you are and use Facebook please join that group.

Nature's Flyers Tricks For Efficient Travel Over The Ocean

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  Nature's flyers (Birds, bats, and insects) have some tricks they use to travel over the ocean without using much energy.  Some travel long distances over the ocean while hunting (sea birds) and others mostly for migrations.   I am collecting some of the tricks nature's flyers use to save energy here with the idea that maybe drones could use some of these eventually. 1. Dynamic Soaring         By moving back and forth between two layers of air that are moving at different velocities an Albatross can soar for long distances over the ocean.  The video below explains how it works.           This trick is a bit like sailboat.  A sailboat has a sort of wing in the air and then a sort wing in the water (keel) and gets energy from air while the keel keeps it from being pushed downwind.   An Albatross gets energy out of the air when it is up high and then pushes off the low air to keep from going downwind.  The Albatross is very efficient in that it uses the same wings for both jobs. 

MPPT in iNav software

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  Solar panels produce the most watts when operated at some ideal voltage called Vmppt. Normally people use special hardware called an MPPT controller to draw power from the solar at that voltage and then convert it to the right voltage for a battery. We have worked out a program for iNav so that this extra hardware and weight won't be needed.   The idea is to adjust the throttle higher if the voltage is higher than ideal and to lower it if the voltage is lower than idea.   Since we already have a computer onboard that knows the battery voltage and controls the motors, we can get things operating at the ideal voltage just using some software.  This will help keep weight down on solar airplanes we make.   We also save any conversion losses or power limitations of the MPPT hardware.   You can see this in the video and the picture after that.     Here is a shot of the program: A shot of the supercapacitor, flight controller, volt meter: The solar out the window: The power mete

Putting Solar on Opterra 2M

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  The manufacuter of our F2X5S solar panels,   solarealdrone.com , said they use Super Glue (with Cyanoacrylate) to glue them on foam planes.   The nice thing is it dries really fast.  We got some Gorilla Super Glue.   Here is a video the company made about how to attach panels to a foam wing and wire them up: To fit the solar panels on our Opterra we needed to remove some bumps on the top of the wing and cut a bit off the edge of the ailerons.   To remove the bumps we used a couple guides and a small hotwire as shown below: We cut out a piece of the aileron and glued it in the old gap to make end section fixed to the rest of the wing, so there was a bit more room for the solar panel. We taped one edge of the solar panel so it could act like a hinge and make the solar panel in the right spot as we were rushing to do the glue.   We lifted it up, put the glue on the foam close to the hinge side, then folded down the solar panel and held it for a minute.  Then we lifted up a bit and put