Design link: https://oshwlab.com/jeffrey098765437/mini-fc

Small demo: https://youtu.be/RGNprXtU4pM

I love drones. I love flying them and building them. The problem is, I'm lazy. I don't like driving 20 mins every day to go fly and would much rather fly from my house. The problem is that all of the drones that I have are big. Like, scary chop your fingers off big. I dont like pissing off my parents with holes in the wall so I want to build a small drone. A drone that has a base of 65mm by 65mm. The problem is that the new technology, DJI O4, takes a lot of power, and most of the commercial ones are not made to handle 1.5 amps at 5V (yes, it sounds like not a lot, but if the Vin is just 3.3V, a 1s lipo, 5V at 1.5 amps is a good amount.) I want to design one that can handle the newest generation of VHD video transmitting in a tiny package.

Basically, a FPV drone is made of a few components. A frame, motors, an ESC (electronic speed controller), a vtx (video transmitter), and an FC (Flight controller). This project aims to redesign an FC that suits my needs. Later, I will also design an ESC, but that's the future.

A flight controller is essentially the brain of the whole drone. It takes commands from your transmitter and turns them into motor power levels. To do this, it needs a couple of things. First, it needs a microcontroller. I chose to use the F405 because it's easy to use, pretty powerful, and I've used it before. An FC also needs a gyro, a small sensor that detects the tilt of the board. This helps the drone stay alive and flying. I chose to use the ICM-42688-P due to its small size and its accuracy. The rest of the componets are there to keep these two things happy. This includes a buck-boast converter to convert the LiPo voltage into a stable 5V. You also need 2 LDOs to convert 5V into 3.3V, one for general use and one for just the gyro, cause it's picky and hates noisy power. Additionally, I added a black box that stores data, which is very helpful when this board crashes/bugs out. I also have some connectors to make connecting everything easy/

I will be using the betaflight firmware because it's the industry standard, and I have used it many times in the past for configuring drones. This FC was designed according to the Betaflight design guidelines and the connector guidelines and is plug/play with any other standard hardware.

Connection to the motors

Schematic:

BOM: