Open Sky Anchor WiFi Drone Brings The GIG

4 pounds 5 ounces, it is light considering everything that is on here! In retrospect in the future I would do the prefiltering and the voltage dependant resistors and capacitors on the ground before the tether. It is not as effective because over the length it is possible to absorb noise agian, but I think it would save maybe 6-8 ounces with that one change alone.

4 pounds 5 ounces, it is light considering everything that is on here! In retrospect in the future I would do the prefiltering and the voltage dependant resistors and capacitors on the ground before the tether. It is not as effective because over the length it is possible to absorb noise agian, but I think it would save maybe 6-8 ounces with that one change alone.

An overnight Digikey delivery to the rescue! The resistor buss alligator clamps are soldered. It can test up to 600 watts. Also I received the missing capacitors and resistor parts for the third power supply.

I used white and black paint pens to make the custom hackaday lettering POP off the arms.

As expected both space and weight on a small drone like this are a premium. I did a quick weight in with the test heatsink and fans still on and we grossed 3 pounds 15 ounces.  Thurindu and I are working on a different rack that angles the power supplies similar to the top picture that encourages fresh airflow across the heatsink. The goal is the trade the heavier heatsinks with fans for custom made heatsinks that bolt to the top of the AC to DC converter. The custom heatsinks would not have fans and I would plan to continue trimming them down until I start to see a rise in temperature under full load. This way I only have the heatsink we need and nothing more in terms of weight. We will monitor this through a thermometer device and FLIR ONE cam.

I have heatsinks and fans now. It is time to start testing the power supply, first that it puts out clean 12volts and second that it can handle a load up to the full 500 watts. We will use the Flir camera on this one as well as a thermometer device to monitor temps. Also we may have an oscilloscope to check the power output is clean as well. ( I mean it should be with as many chokes, capacitors and voltage dependent resistors in the circuit. 

This project requires a highly reliable and relatively powerful power supply. It needs to operate in harsh conditions, handle near full load constantly and also have a built in backup in case of overheating or any other failure causing output to drop to the electronics or motors. I am using a combination of Switching AC to DC Module with power smoothing and onboard dual Lipo battery backup as well. It is not done, but here is the progress before dinner. On the DC side (was o the right) there are four slots for Velcro straps and two Deans connectors to add or swap our battery connections. There is nothing to prevent a larger battery from being plugged up, but they would need to be stored somewhere other than on the small footprint I made for a emergency backup battery. In hindsight and better planning I could have reduced the board size about an inch in length, but overall most the components are packed tightly together. I will put a heat shield on both rows of capacitors with the gold foil I have to help reduce radiant heat from the heatsink. This is a bare plate with no heatsink. I have four heatsink options, one of them having forced air from fans, but as Dink pointed out, there should be plenty of airflow under the drones downward draft from the twelve props.

In order to establish good clearance from the carbon rods and the bottom set of propellers , we designed a “universal” spacer that could be used on a variety of drone frames besides this F550 style one. 

All 3D printed mini dish with gold foil glued to the inside of the dish. This is meant to clamp to the cross braces on the landing gear. It is always pointed at the ground for drone to ground communications link.

Two zip ties on each set of ESCs hold them securely under the arms. They are vented from the top , sides and open bottom so cooling should not be an issue. There are two 30a ESCs beside each other in this arrangement.