I began my RC drone hobby with the first generation DJI Mini. My second drone was a DJI Mini 3 with the RC (built in screen) remote. Third was the disastrous FIMI X8 Pro/TX10A. My last consumer drone is by far the best of the four, a DJI Air 3/RC2 kit. As good as the Air 3 is, I wanted more. I do not like how any consumer drone platform you can choose (particularly DJI) locks you into their product ecosystem. Sure, there are a few minor accessories by outside companies that are compatible, but only small cosmetic or functional things. Never major components. If I wanted heavy lift capability or infrared camera payload, it typically meant buying yet another entire drone system.
Because of these things, I have transitioned to large DIY multirotor drone platforms. (Not small FPV drones) I'm curious if anyone else has made a similar transition and what your reasons and experiences have been. Anyone?
Sure. The starting point was an Arris M900 frame, motor, ESC, and propeller combo. I purchased my kit from RC Wing and it was $559. Next, you have to decide which firmware platform you want to use. The major options are ArduPilot (ArduCopter), PX4, Betaflight, and INAV. This is an important decision as it will dictate which flight controller you will need and affect which advanced functions will be available. Nearly every blog or website about getting started with DIY drones will tell you to build a small inexpensive FPV drone for your first build. To be fair, that's not bad advice. That is not what I did, but it's still not bad advice. I say this because it's likely that you will flip or crash a time or two. I am an industrial automation engineer, so I'm pretty capable with stuff like this and I have flipped my Arris M900 twice. Both times were due to faulty components but it still happened. The good news is the Arris frame is very strong and I didn't break anything either time.
Betaflight is, perhaps the easiest platform to learn but it's also the most limited. If you plan to have functions similar to DJI drones such as vehicle/people tracking or automated flights that go from one way point to the next, don't choose Betaflight. Betaflight does have basic GPS functions like RTL (Return To Launch) but that's about it. I don't know much about INAV other than it's supposed to be similar to Betaflight. The other 2 firmware types are ArduPilot and PX4. These are essentially the same. ArduPilot and PX4 were once the same platform but split into separate platforms several years ago. If you Google ArduPilot vs PX4 you will find that the big difference is the type of open source firmware license each employee. ArduPilot requires all developers to share their upgrades or modifications to the ArduPilot community for screening and approval. If the code is good, it will be added to the ArduPilot database. PX4 does not require any modifications to be shared. Basically PX4 is a more basic platform that's often used by manufacturers who want to develop their own versions for proprietary projects. ArduPilot is the platform I chose. There's a version for nearly any type of RC vehicle. Multirotor, helicopter, fixed wing, boats, and land vehicles like cars trucks or robotic tracked vehicles. I don't know about RC devices like a biped or quadraped walking robot "dogs" etc.
For my quad drone, I used Arducopter. Arducopter has the functionality to do anything that you can think of with a drone. From FPV drones to completely automated drones that are launched and operated by a computer. Things like GPS way point missions to high end camera and gimbal control, ArduPilot/Arducopter can do it all. The downside is it's more complicated to learn the system. Nit hard but harder than Betaflight.
Once I decided on the firmware I wanted to use it was time to pick out a flight controller and radio system. I started with DJI drones before changing the DIY. I don't care for radios that you have to attach a cellphone to in order to have a screen. I much prefer all in one transmitters which combine vehicle control, telemetry and video stream all on one device. There are basically 3 options, Skydroid, Herelink, SIYI, and to a lesser degree Tarot. Except for Herelink the other systems will work with a fairly wide range of Flight Controller brands. Herelink only works with "Cube" autopilot/Flight controllers. I chose the SIYI MK32 remote controller/transmitter. It has a bright 7 inch touch screen, works with a wide variety of cameras and Flight Controllers and was cheaper than the other brands with 7 inch screen. Now, SIYI has the UniRC 7 radio which has up to 40km control/video range. I noticed that Skydroid has a new G series of transmitters with 20km range. Unless you go with fixed wing, that kind of range isn't necessary. Multirotors are very versatile but require more power to stay in the air. Plus BVLOS is illegal anyway. I look for long range control because that also equates to better control and reception in urban areas or anywhere there is a lot of interference. Because I am new to DIY drones and after I decided on the SIYI transmitter, I chose the SIYI N7 Autopilot and Flight Controller as well as a SIYI A8 4k camera/3 axis gimbal. I chose all SIYI components because I assumed that they would all work together in an easier and more seamless way. Turns out I was right. The camera and gimbal were literally plug n play. As soon as I connected the camera to the AirUnit (the receiver that goes on the drone) and turned the system on, I automatically had a great video feed and gimbal control. (One less thing to worry about). The SIYI N7 Flight controller was a little more complicated but still fairly easy. Other than those things you will need at least one battery and a battery charger. For big Multirotors like this one, the battery is expensive. I'm using a Tattu Plus 6s lipo battery with 22,000mAh capacity and a 25c discharge rate. My other battery is a Zeee 6s 20,000mAh battery with a 10c discharge rate. I'm not very confident with the 10c discharge rate. This number represents how much amperage the battery can provide per minute. A racing drone that needs super quick acceleration will have a 80c to 120c discharge rate. A large, slower moving drone like mine doesn't require a high discharge rate. Also the cell count is important. The higher the cell count the higher the voltage of the battery. Most big drones use a 6s battery system or larger. The big Agricultural sprayer drones use up to 18s (18 cell) batteries. This is enough to get you started. I began my first drone build in December and I just made my first test flight last week. There is a lot of research that goes into building a drone and it can get frustrating at times. But it's been a very rewarding experience for me and I plan to continue building drones. Feel free to reach out anytime.
