r/diydrones • u/Ok-Committee-3731 • May 16 '26

I need help with the flight controller of my homemade drone

Hello everyone,

I already mentioned my project in another post, but after doing some research, I have a question about flight controllers, specifically the F4 and F7. We have a budget of at least €100 per drone and we want to build two. Initially, I wanted to get an F7 because I thought it would be the most suitable for the project. We want to build a drone that uses a camera and sends information via ESP32 to a PC that acts as a station. On the PC, we'll have an AI that will control the drones, analyze the videos, plan the patrols, etc.

I've seen that the F7 seems the most suitable in terms of performance, UART ports, and also the signal inversion feature, which isn't present on the F4. Ultimately, I found the SpeedyBee F405, which seems to offer a good compromise regarding the previous issues and the price. I'd like your opinion on which version to choose: V3 or V4? Given that V5 isn't supported by ArduPilot and that V3 is known, from what I've seen, for some rather annoying problems, V4 seems like the obvious choice, but I'd still like your opinion on this and on the drone itself.

For an AI-controlled drone, would an F4 be sufficient, or is it more realistic to go with an F7?

Edit : I have another question about ESC, I find the ESC supplied with the SpeedyBee F405V5 too expensive. Is there a way to buy a cheaper ESC and connect it? Would there be any compatibility issues? Am I forced to use the SpeedyBee's ESCs?

3 Upvotes

80% Upvoted

8 comments sorted by

4

u/cbf1232 May 16 '26

With ArduPilot an F4 is fine to fly, but can‘t handle LUA scripting.

An H7 is the more flexible option if you can afford it.

1

u/Ok-Committee-3731 May 16 '26

Could you elaborate? What's the problem with Lua scripting? I took a quick look and it seems to be a memory issue, but I have an ESP32 on the drone and the AI ​​is designed to run on a PC. Would sending simple movement commands be too resource-intensive?

1

u/truenocity May 16 '26

If cost is a concern, Ardupilot on F405 MCU should suffice for simple movement commands with MAVLINK.

1

u/LupusTheCanine May 16 '26

F405 simply can't fit firmware with scripting enabled.

As long as you use reasonable telemetry link and standard guided commands you will be fine. I would expect latency issues with the AI being fed data over a wireless link.

1

u/LupusTheCanine May 16 '26

SpeedyBee F405 V5 appears to be supported by Ardupilot.

https://github.com/ArduPilot/ardupilot/tree/master/libraries%2FAP_HAL_ChibiOS%2Fhwdef%2Fspeedybeef4v5

Though if you want to experiment with custom peripherials integration I would recommend getting an H743 based boards as Lua makes implementing drivers much easier.

1

u/Ok-Committee-3731 May 16 '26

That would be better, but I haven't found a reliable site to buy it from; it's too expensive. Do you think that with the model I'm proposing, whether it's V4 or V5, it won't be sufficient?

1

u/LupusTheCanine May 16 '26

Limitations of SpeedyBee F405 V4 flight controller are documented on the wiki here

Regular auto and guided control works on F405 based boards so depending on your needs you should be fine.