Open Sky Anchor WiFi Drone Brings The GIG

The first test prints on this design, which is the second iteration, just started. I am printing tests in PLA, but I will consider getting PETG for the airworthy version. I do not have PETG on hand and I have never printed with it, though I hear it is a lot like PLA , but hotter.

Ok We have been working to design a new arm style that has a quick disconnect option and also can fold away and stay assembled for temporary transport. This is also useful when calibrating sensors as handling a drone while calibrating by yourself can be a touch task when the arms are attached and spanned out. Quick disconnects can resolve this and may long term storage options much more compact.

Two through holes take long thin bolts. Removing only one allows the arms to fold down for easier handling and transport in a small vehicle. I drive a Mitsubishi IMIEV Electric bubble, for example, so size matters. :)

Ok so Part 107a FAA rules say I need to have a regular transmitter and receiver on the aircraft in the event that the Raspberry Pi malfunctions or becomes disconnected as a backup. So I bit the bullet and bought a reputable radio and receiver combo from Radio Link, and Pix Hawk from Radio Link as well for stabilization. The goal, of course, is for this to be remotely connected to the onboard raspberry pi as a mission planner and could receive new missions or adjustments remotely through WiFi without having to manually pilot it. One step at a time though. Hopefully I get some bootstrap money to get the power supply, wire , Ethernet and stuff like that as this is not the cheapest endeavor. Even so, it is tens of thousands less than the nearest option if you are trying to setup a tethered drone. There are only a handful of companies that will sell you a tether kit and even then they start at $12,000 for something you can build yourself for 500-1000 dollars.

So I needed to do a great deal of research on this one. I have found some AC to DC converters that are both high quality , within budget and are ultra light. 250 gram, less than 1/4 the weight of the nearest competitor I was looking and and supports voltages up to 240 volts meaning I could reduce the gauge of the tether and further reduce the weight.

To get 1000 watts which is more likely what I would go for I would run two in parallel. Redundancy is important for reliability. I will be able to get these if and when I get a boot strap award to go forward with the project, which would be really nice because I already have $800 of my own money into this project. #BrokeInventor

This is a modified DJI style f450/f550 arm, which has been cloned dozens of times and is more popular now than ever because DJI retired the style. One of the aspects of running dual motors on one arm is the weight issue.  Double motors , motor controllers and wiring can increase weight. Some buy frames like a hex 6 from Tarot for example that is made from a bunch of carbon fiber tubes. There are a few reasons I am not doing this. First, The  carbon frames can be 200-600 dollars by themselves. If you buy china direct it is cheaper, but then there is the risk of getting fake carbon fiber that is mostly fiberglass or even plastic that has been hydrodipped to look like carbon.  3D printing is a good alternative to carbon in the sense you can make them lighter with infill, and still get a functional end product. It may not be carbon fiber, but functional is what we are looking for right now. Initially I will use PLA, but for motor temperature reasons I may swap to PETG to handle higher heat and still maintain a light weight part.

Below is a iteration of the F450/F550 Drone arm that is basically two full arms slapped together with 8 supports connecting them. I am sure this is very stiff, but it also more than doubles the material and weight of the arms. Multiply that few ounces by 6 and you added an extra pound to your aircraft for no good reason.

In addition, I am not fond of the look either. It looks like it would fly like a brick.

So I appreciate this guys efforts in his design , but we need to go a little lighter...

This is my idea for the long range directional antenna, I have the choice of either running an ethernet up to it, or having a second AP that perhaps is pointed down for example or 360 degrees so that there is general Wifi in the basecamp area as well.

https://www.amazon.com/EnGenius-Technologies-EnStation5-AC-Outdoor-Wireless/dp/B073H5KSSJ/ref=sr_1_50?dchild=1&keywords=directional+wifi+ap+2.4&qid=1594271959&s=electronics&sr=1-50#customerReviews

Based on others reporting a max 540 watts and 360 watts hovering with conservative flying, I am planning to have a 16 gauge aluminum wire that is 1.08 pounds per 100 foot, so 2.16 pounds for  200 foot. The planned ceiling that I plan to operate under is 10 amps , 1000 watts

https://www.amazon.com/gp/product/B006LW0W5Y/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

Ok so without too much explanation, the power supply I use on the air frame needs to be powerful and also reliable. Additionally it much be compact and light as possible. What ever unit I get I will do as much as possible to reduce the weight, likely removing the steel or aluminum casing, as the board will have plenty of airflow opportunity right in the middle of 6 x 10 inch props. In the future I could use a vacuum table to vacuum form a clear or thin white plastic cover just for safety from touching a 110v transformer or capacitors.

First option I found at only 1.9 pounds WITH THE CASE, losing the case could make a big difference.

https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2274719&productId=2274719

https://www.jameco.com/Jameco/Products/ProdDS/2274703.pdf

Second Option on Amazon that is physically larger and claims a 100 watts more for a rating but there is also the obvious draw back that the board is a little wider, but the weight is about the same.

https://www.amazon.com/gp/product/B0781V1D7Q/ref=ox_sc_act_title_8?smid=A2231Y3TO3624O&psc=1

Here is a third options, a little heavier and larger than the slim line but agian also claiming 600 watts instead of 500

https://www.amazon.com/gp/product/B082NSVWJY/ref=ox_sc_act_title_11?smid=A27SLSMOK7EK4X&psc=1

I know there are likely mosfets that need to be cooler so I would opt in for smaller dedicated heat sinks for those and loose the heavier case if at all possible. If nothing else I could drill large holes in the case to swiss cheese it, giving it more airflow and also reducing the weight from the casing. Right now I am leaning towards the first option as the supplier is more credible and it has a smaller form factor.

RGB  flexible matrix 5 units $35.88 each

https://www.amazon.com/gp/product/B01DC0IPVU/ref=ox_sc_act_title_2?smid=A35UAT07QG3EC6&psc=1

PLA Filament 2.2kg

I imagine this will take 4 rolls a filament as an estimate, around $25 each.

F550 DJI frame

OK so when going through the use case and proof of concept phase. Realistically I need to build two air frames to demonstrate the function of rapid deployment and air to air radio communication bridge. There are other functions too we will discuss, but this is the initial basic use case.

I try to be clear about what I am using and also offer similar alternatives for those who one day want to duplicate the results.

I scored another good deal, but take in mind that this format has been cloned several times and you can get entire kits will all parts like remote and flight controller for this price, however we have obvious time constraints as estimated shipping from China would have put us right before the end of the competition.

Here is an example of buying a full kit with pretty much everything you need all in one for a low price

https://www.amazon.com/Hobbypower-Hexacopter-Pixhawk-Controller-Simonk/dp/B0759B6SD5/ref=sr_1_1?dchild=1&keywords=f550+drone&qid=1593989739&sr=8-1

Above is an example of China Direct close shipment.