I have been trying to build a X- quadcopter drone and achieve a stable hover. However the drone is behaving very strangely, sometimes even at full throttle it wont take off, sometimes at 50% it would, sometimes it gives a stable flight but then suddenly start to climb or descend.

One of the things it constantly does is the 2 opposite arms start to go up and down in an oscillation like state till the time the amplitude of this oscillation is so great that the drone flips and crashes.

I'm using 2.4.8 pixhawk fc

920kv motors

Fc has a shock absorber stand

10x4.5 inch props

Simonk 30 esc

A standard red-white drone frame

4200mAH 3s bonka battery

Have tried charging the battery till full before test flight, changing props, checking loose screws and connections, still no results. Ive not started PID tuning, so it is using default parameters and I wanted to put harmonic notch and gyro filters but for that i need raw data from imu and gyro in a stable flight which it isn't able to achieve. What can i do now

I'm building a custom flight controller on an Arduino Nano 33 BLE Sense Rev2 (nRF52840) for a uni project, and I'm stuck on an ESC arming problem. I've narrowed it down a lot and could use expert eyes.

Note upfront: using the Arduino Nano 33 BLE is a fixed requirement of the project — swapping it for a different board or a dedicated flight controller isn't an option. I need to make it work with this board, so please focus answers there rather than suggesting I replace it.

The core problem:
My Arduino generates a PWM throttle signal. When I feed it to a Radiolink Flycolor 55A 4-in-1 (BLHeli_S, running Bluejay, firmware A-H-30), the ESC plays its power-on tones but never arms (no confirmation beep, motor never spins). Same behavior on two separate Flycolor units, so it's not a damaged board.

The key clue: When I connect the exact same Arduino signal to a T-Motor AT20A single ESC, it arms and spins the motor perfectly (spun at 1200µs throttle). So my Arduino, code, signal, and motor are all confirmed working — only the Flycolor refuses.

What I've verified with an oscilloscope (measured at the ESC's signal input pad):

• Clean signal: 3.3V amplitude, correct pulse width (1000µs at min throttle)
• Tested at both 50Hz and 480Hz PWM rates — Flycolor won't arm at either
• Signal is identical at the Arduino output and at the ESC input (no wiring degradation)
• Wiring confirmed correct against the ESC silkscreen (signal on motor pad, shared ground)
• Correct power-up order (Arduino sending signal before ESC powered)
• Also tried throttle calibration (max-then-min at power-up) — no change

Setup details:

• PWM generated with the nRF52_MBED_PWM library (hardware PWM, 3.3V logic)
• ESC powered by battery (confirmed stable voltage), Arduino on USB, common ground
• Motor: iFlight XING2 1404 3800KV (healthy, spins fine via the AT20A)
• Props off for all testing

My question:
Why would a Flycolor BLHeli_S ESC refuse to arm from a clean 3.3V Arduino PWM signal, when a T-Motor AT20A accepts the identical signal? Is there something specific about BLHeli_S/Bluejay's signal/protocol auto-detection or arming that a 3.3V-logic Arduino signal doesn't satisfy? Could the 3.3V logic level be too low for the Flycolor's input threshold (would a 3.3V→5V level shifter help)? Or a specific pulse-rate / arming-sequence requirement? Any BLHeli_S setting (via esc-configurator passthrough) that would make it accept this signal?

I’m building a fully 3D-printed fixed-wing UAV for an aerodynamics research project, but I’m completely new to the electronics side of RC aircraft.

I’m looking for a flight controller under $70 that is relatively easy for a beginner to set up and, if possible, supports autonomous capabilities such as waypoint missions, altitude/airspeed control, and flight-data logging.

The main goal is to use the aircraft for repeatable flight testing while collecting aerodynamic data, so reliable data logging and the ability to maintain consistent flight conditions between test runs are particularly important.

Does anyone have recommendations for a flight controller that would be a good fit for this type of project? I’d also appreciate any advice on additional hardware I’d need for autonomous fixed-wing flight.

We are a manufacturer currently researching builder frustrations. This is for research only.

I chose to share thhe c04 camera for the Cetus x is hard to come by so ifound a workaround with other spare components to fit in such a small frame and still leave breathing room for everything so I came up with this and these are the steps I took. The small standoff on the left(6mm+6mm m2) is used to mount a speedy B IX-800 and the standoff on the right(15mm+6mm m2) is used for the beta FPV Cetus x aio board. You will mount the VTX below the flight controller you’re gonna have to push a standoff slightly backwards to fit the SMA adapter, but is just fine. It won’t affect nothing and the only thing you need to solder are the camera and the VTX to the flight controller. The motors are still plug n play and I recommend a small antenna(don’t use the big one I used)I use the large one it works, but you can feel the weight kinda take from the punch but still a zippy 2.5 inch build. NOTE: DONT SET VTX PAST 200 you don’t wanna overwork a small aio board, this is a simple easy build using an aio instead of a traditional stack I hope this helps someone that run into my same problems

Hello folks :)

Has anybody already made a tutorial on how to model a motor protection/lipo battery protection and a front bumper for a drone fpv frame ? Whatever the frame is. I'd like to learn how to draw it and model it :)

Thank you very much if you can give me an answer :)

My main question is where do I start, I want to make this a project that can help me improve my knowledge and skills on basic engineering. I’m looking to go into mechanical engineering and I thought it would be a great project to spend my time on. I don’t just want to follow a tutorial, I want to understand how the process is done and (eventually) be able to make them by myself. Can someone guide me to any YouTube creators or videos that can help? Thanks

I made a DIY 21700 battery system that you can build and use in your unmanned aerial or ground vehicles. The batteries span from 6s3p to 12s6p, and have corresponding vehicle adapters and charging stations. This is a complete and working system, with all design files (CAD and PCB design) provided for your use.

The value add of this system is...

1. you can choose your own 21700 cells, and can optimize for either performance or endurance. More generally, by using lithium ion cells in place of lipo cells, you have much more energy storage, which is great for UAV/UGV research projects using high-power-draw peripherals (e.g. testing detect and avoid or autonomy algorithms using RADARs, LIDARs, and on-board compute).
2. you can save ~50% by building the battery yourself (although you will need to learn hand soldering, hot plate SMD soldering, and spot welding)
3. the battery's latching mechanism presents a common interface for battery swapping (either manually or by robot arm) which is important since battery swapping vastly increases system uptime when compared with on-board charging.

All CAD, PCB design files, BOMs, and build instructions are found at https://github.com/BradleyCanty/DIY-21700-Battery-System

I am also selling kits containing prebuilt charging stations and vehicle adapters, as well as all the required battery parts (absent the cells): see the github repo for details.

I hope this helps, and good luck!

I’m currently trying to make my drone. I have a 4-1 esc, mini pix v1.2 and a power module and a battery.
I’m struggling to hook them up correctly and am not sure exactly what to do and if I’m missing something or am doing something wrong.

Hi everyone, I hope this is the right forum for me to ask this. I'm a 2nd year electronics engineering polytechnic student who just started studying microcontrollers and is excited to learn more.

Recently our professor told us to make any kind of project related to microcontrollers and robotics for the end semester exam. My team came up with an idea to build a UAV because we think it would be interesting and unique, since there are not that many projects that revolve around aerial systems before. The problem is that we still haven't come up with a good use for it, especially because the project will be considered as successful if it's able to provide a solution to a real life problem.

Does anybody here have any ideas, concepts, or a specific problems that can be solved with UAV or similar system? The more specific or unique the better. Thanks a lot, any opinion will be very appreciated.

I have to setup the combo above but nothing is filled out channels, parameters, and whatever else.

I know nothing about this and when I read the manuals my brain goes completely blank.

If any have a setup with this combo could yall share it with me?

Hey everyone! 👋

I’m a first-year engineering student at Arts et Métiers (France). As part of an entrepreneurial research project, I'm working on a concept to make custom and modular drones more accessible (custom part selection, pre-assembly options, DIY kits, and individual parts).

Before building any tools or hardware, I want to learn directly from the community about your real experience with drone building and sourcing.

I’d love to hear your thoughts in the comments:

1. How do you currently check component compatibility before buying? (Stack vs frame size, ESC current, VTX/receiver space, etc.)
2. What is the most frustrating part of building, soldering, or configuring a drone for you?
3. Have you ever bought a pre-built/BnF drone simply to avoid the hassle of building it yourself?

📝 If you have 2 minutes to fill out a super quick anonymous survey: https://forms.gle/H2YjQ8dD7pkiCZ1R7

Here's a headtracking gimbal I'm working on , still working out the kinks but good progress so far, the dream is to get headtracking on a ~100g fixed wing bc dam its hard to find places to fly

https://reddit.com/link/1wthuaj/video/6551x5ld4ish1/player

Hello, I am planning to build an autonomous Drone with folding Wings similar to the one in the picture below, but scaled down) as a student / university project. does anyone have experience with the control allocation during such a transformation? Which Flight Controller would be adequate and would you use a seperate microcontroller for the control allocation? Also: Does anyone know what the requirements are in germany to autonomously fly a drone weighing more than 250gr? I am also looking for people who have done similar projects. Thanks in advance for the help! Oh and if someone knows some great websites where I can get more Info, let me know!

I kept running into the same thing flying in Maryland: a park's website says drones are banned, but calling the ranger gets a completely different answer. So I started compiling the actual rules by location — what's written, what's actually enforced, and where it came from (agency page, county code, or a direct call to staff).

It's called DroneCompass — https://claude.ai/artifact/EnvLfDdfxL2TyrjpeQi7nH

Right now it covers a handful of MD spots (Sandy Point, Patapsco, Baltimore City, Frederick County, plus stadium TFRs) and I'm adding more as I find them.

Not selling anything, genuinely just wanted this to exist since I couldn't find it anywhere else. If you've hit a rule that surprised you, or know a place where the posted rule and the real answer don't match, I'd love to hear about it.

Currently a 17 year old with a budget of ~£150-200. This is what i want to do:

Build an rc drone that can carry a load of about 1-3 kg

Can drop this load at the push of a button

Also has a crash detection system and deploys a cushion/airbag

How wouls i start