YMFC-32| Altitude hold programming and implementation| The Arduino - STM32 DIY autonomous drone 

I’ve implemented something similar using an STM32, I was taking 20 point averages of a value, after some analysis I realised a 1D Kalman Filter was more responsive, used less processing power and gave a smoother output. Estimate(new) = Estimate(old) + gain(0.15)*(measurement - estimate(old) ). Gains around the 0.1-0.3 mark have good smoothing ability without too much lag. Hope that’s useful.

Nice to see you are further developing the project! I myself got into multicopter because of your DIY projects, both YMFC-AL and -32. My first iteration was with atmega328p using your code, and then, again from you, I discovered stm32 and got me some boards. I was having some flight stability issues, I guess because of the unstable power from the ESCs. But now with a dedicated mosfet I had laying around things are improving! I keep a log of my build on rcgroups if you want to have a giggle at my progress so far.

What fantastic attention to detail of the sort hopefully turns this project from ‘it worked for me’ to one that should work when people build their own with different motors/ rotors/ ESCs/batteries/bregulators/arometer mounting etc. etcI built a YMFC-AL & modified the code a little. Rock solid stable in flight, but the hardest thing to do when flying was to keep it level. Although changing the throttle response on the RC transmitter helped a lot, I figured adding a barometer to YMFC-AL was doable. It didn’t work & I never worked out why - but there are at least 3 ‘gotchas’ explained in this upload.

I am very excited about this serie.

Few points: 1. Both the I2C ports of stm32f103 are 5V tolerant, then why to worry about I2C signal levels? 2. Try gy-86 breakout board. It contains mpu6050, ms5611 and hmc5883l all on a single board! Here's what I do: 1. I request temperature with 1024 osr and pressure with 4096 osr as follows: -> Setup() - request temperature with 1024 osr -> loop 0 - read and calculate temperature, request pressure with 4096 osr -> loop 1 - idle -> loop 2 - idle -> loop 3 - read and calculate pressure, request temperature for next loop After calculating altitude I take average of 16 altitude readings and update baro_updated flag so that pid outputs are calculated only when new averaged data is available. This gives accurate altitude with 62.5Hz refresh rate and 7cm precision. 2. When my throttle reaches hover point, I activate the altitude hold algo. When the throttle is raised I increase the setpoint of altitude hold algo and vice versa so that altitude hold algo is always running and the flight is more stable. Great video as always :)

Hey joop...I am a big fan of your project and your knowledge and the way you described the project it just awesome..

You are amazing! There is so much practical info in your videos. Not just theory that only works on paper.

My dear Joop, thank you so so much for you passion and inspiration of drone and embedded programing. I was one of your big fan when I studied in university. Now I am working on software field in Japan but I can not forget the time I was in love with Arduino and AVR MCU. I think that I will comeback to my truly passion in the future. Thanks so much for your inspiration :)

Good tutorial! Unfortunately averaging 20 measurements seems like a lot of time with this output data rate. Ive tried median filter with 3 measurements and it gets rid of those annoying spikes aswell. Then Ive used "simple" kalman filter and complementary filter at the end (like you did). Ive noticed very fast response with smooth signal :). Its recommended to have very smooth and responsive signal for altitude hold. D term of altitude hold algorithm put a lot of stress on battery esc and engines.

To get rid of the 5V level shifting you can also just desolder the two 5V pull-ups on the clock and data lines (and - if you don't have pull-ups elsewhere - add some new pull-ups to 3.3V). This is a lot easier than trying to solder wires to the 3.3V side.

This is a great failsafe function. Definitely getting an FC that has an baro on my next built. Those F7 boards are looking mighty-nice 👌

Excellent video. Thanks a lot for the dedication you put in this project.

excellent contribution, I have been following your projects for a while now and I have decided to replicate your YMFC autonomus project. One question, is there any way to get the PCB that appears in the videos? Is there a way to buy it? Sincerely jose

You could use lidar sensor with accelerometer (which you already have onboard) to get altitude when you're in horizontal position in x and y and use altimeter for getting altitudes beyond the lidar range.

Hi Mr. Brokking why when I enable alt hold quad fly up? hover throttle about +/- 1500 and I guarantee barometer reading is good

It s a pleasure to see your videos, thank you for sharing your passion :)

Hello, Why did you use a pressure sensor instead of using the altitude value from the gps when implememting altitude hold? Is it because the gps altitude value is not too accurate or there is another reason? Thanks in advance.

Great job, and easy to follow. Thank you again

I am happy to see your new video Mr. Joop :)

Dear Joop, thanks again for this informative video. Doesn't the MS5611 have a read out of "uncompensated" pressure data? Because your FC is merely interested in changes of pressure and temperature is considered mostly stable, one probably can neglect the temperature reading and calculation. Just using the raw values ...

Awesome! I have one notice: Why not to activate altitude-hold when throttle became stabilized? I mean when difference in throttle is about some value of error? In your case I have to remember to center stick every time. In my case it'll calculate altitude for any value of throttle

Great work, I would like to know more on that telemetry system. Looks interesting.

Great project Joop. Really good ideas n developments there.

Thank you! It's very interesting, can't wait to repeat it by myself.

nice job bro. i always new videos from you. thanks

Thanks,Mister I study a lot of it from you ,say Thanks from Taiwan.

interesting, thanks. just curious, at the end when you are flying, on the right, is that the highest mountain in Holland?

Thanks joob, excellent work, I really appreciate the effort that you put on, GREAT

Nice job! Very clear explanation!

Hey Joop, as a hobbyist, recently I have been following your videos, instructions and have successfully flown auto leveling drone. Your simple and yet effective way of explaining fundamentals is amazing! After auto level, I am now trying out the altitude control. Here I have trouble working with MS5611. To experiment, I have taken snippet of your code to play with MS5611. My code reads very high raw temperature & pressure values, almost like full scale. Any suggestion what could be the issue? Could the daylight be interfering with MS5611 (i did putting the breakout in a closed box). Or could the light from LED on the GY-63 breakout interfere with pressure reading?

Hello sir. You wrote about getting the temperature of Barometer. "After that we can poll the pressure data and immediately request the temperature. And again we need to wait for 2 loops before the temperature data becomes available." Why not using the temperature value from gyro, which created in every loop.

have you thought about trying your codes on a Multiwii flight controller, your videos are very inspirational.

Nice project and excellent explanation of how works this system for hold altitud, i want suggest in the future if possible can you explaint how works a code of ESC controller without sensors, i see many tries in RU-vid but not work good, thanks for share.

Wow finally you decided to share it with us. Thanks for all your efforts

Dude you are awesome. I will use your technique in share market also. For scalping

Thanks for sharing this filtering method, I may just try something like that myself. Out of interest, would 2048 not have been sufficient resolution?

Hi....May I know if you have some lessons about the openCV and image processing....I like your codes...They are easy to understand and can be readily implemented without using libraries as you explained them very well......Thank You :)

I use arduino ONU and I make a quad like your ymsc-AL (see your video) how can I add attitude hold to my ymsc-Al.. Ymsc3d is very costly for me... Please tell?

@Joop Brokking I dont know if you still read the comments, but I am building the YMFC-32 at the moment. In one of yor videos you showed the telemetry of the copter on a notebook an there was a max altitude set. I dont have found this in the code you have published. Is there any way to limit the height it can fly? In my country a restriction of 100m is given and I want to add this in the software.

can you please provide 3d design of that which you build in cnc machine. you are doing great work. but please help me. and also can provide the detail connection of how to connect STM and barometer.

Joop, In this video @ 2:12 you use a PCB. Any plans to publish the scheme and design? Or did I miss it?

Hello. I really like your project. Does the Quadcopter have enough lift to get for example a camera / gopro in the air? Which ways can you mount a camera like a gopro or a camera for fpv funcionality? Whats the flight time you can get with the battery? And the last question: Whats the weight of the drone? Thank you very much in advance.

Hello sir Joop Brokking, really thank you for your wonderful work, I learned a lot from YMFC-AL, which I am currently mastering. I recently developed the YMFC-32 with GPS, normal flight works fine, but I am having difficulty maintaining altitude and position, I have already traveled a wide range of PID values ​​for GPS and altitude. The altitude still works but is not always stable, my real concern is position hold, when I activate it the drone lands on its own, then the propellers stop after 5s. Please answer items.

Great work Joop !!! Can I modify and use this code on YMFC-AL (with. Arduino Mega) + GY-BMP280 Sensor ?

Hey Joop, I always wondered how you graph the data with the arduino software(not excel) because I want to see a live feed of sensor data.

Hello, and thanks again for this wonderful fun and educational project. I am however confused regarding the need to power the MS5611 breakout board with 3.3 V. As far as I understand, the I2C pins used on the STM32 (B10/B11 - RX3.TX3) are tolerant to 5V. And indeed both the HMC5883L and the MPU6050 are power with 5V and connected to the same I2C line. Since both the MS5611 board and the STM32 pins accept 5V, why should we power the MS5611 board with 3.3V ? Thanks for any information.

Hello, In the complementary filter, does the coefficient value should always add up to 1?

Thanks my frinds, so good work fantastic arduino profec man.

Hello Mr .Brokking . i have seen u r video on ms5611 , in the video u are explain 25 ms to acquire the ms5611 data . i had developed ms5611 code where i use my one loop as count each loop is 2ms , once it reaches 10 i acquire the data and it works well .I just want to know why this extra 5 ms u had used in u r code . i have seen u had made a black container to over come the light sensitivity of ms5611 , i have used a black tape ( not touching the sensor) but i see a drift in the altitude over a period of time . do the black tape cause the drift ? or drifting the air pressure is normal for me i( the diff is around 2 meter in 30 minuts ). can you share ur experience. thanks in advance .

Hi. I have a project. In my project, I designed a four-engine drone. My teacher made it a condition for me to graduate. This condition is that the drone will go down at the desired speed, it will go down at 6 m/s by increasing the pwm according to the height, and I am thinking of doing this task with a pixhawk, which will fix the altitude at 100 meters. Can I change the descent speed continuously by adjusting the pwm according to the altitude? (It will be a fully autonomous system). I would be very happy if you have any suggestions.

Is there any difference your altitude holding technique and beta flight ? I am just asking, I don't know what are the techniques used by the other stable drones and commercial versions, like DJI. Please can you enlighten me Mr. Brokking.

Hi, can I use the MS5611 barometer on the stm32 the controller board (PCB) and by covering all the flight controller with a special case?

Finally come!

Another great work Thanks

I noticed that it was a little windy in the very last video. How did you keep the copter from drifting away in any direction? Some new copters use a downward facing camera to keep them from drifting.

Can ultrasonic module be used for the purpose of altitude hold

Thank you. Appreciate it very much

Only this code can be used with any flight controller?

Can we connect resistors to the pins of the MS-5611 to step down 5v to 3.3v

Sir, is it possible to use brush motor with same code in arduino ??

May I ask a question? ! Do you calculate PID altitude in every loop ( 4 microseconds ), or every time the actual_pressure is updated?

Why can't you use timer interrupt to get data from pressure sensor ? Or does the sensor itself offers some interrupt??

Amazing job

How can I add servos or a 12v moter to this ?

hi where is the schematic of this case ? i would like to do it with 3d printer can i have measure i will design a .stl file and there s no other way to welded wire on CMS components ?

nice complicated job !

Is the VCC of the ms5611 connected to 5V or to 3.3V?

so smart, fantastic

Great !!! I want to be like you. Thanks!

very good work , thanksfor the share

Sir can i use chaper version of barometric pressure sensor

i really enjoy watching your video's ! but i would really like you to explain this to a flat erather :))

Hello brooking sir!! I am trying to develop a flight controller by stm32f4 (according to our future requirement)..i have already spent 9 months on it, to only fail..so could we use the same stm32f1 code for stm32f4 (by changing the timer configurations accordinh to stm32f4 add on and necessary pin outs)..and yes how much do i need to change the timer configuration..

great effort, good representatio brother. please make RC control with LoRa sx1276/1278 Module with arduino.

why not use an IR sensor/camera/ultrasonic module instead of this? IR and ultrasonic is unaffected by light changes, you could have ultrasonic for low altitude and IR for above.

I made a quadcopter with P I D method. But even at the best p i d values, it doesnt balance well its position. 2-4 degree vibration. 2-3 vibration per second. What can i do to fix this? ;(

Hello sir I am Sourav. Sir can I use arduino uno or mini instead of Stm32

Good job.

Sir I am not able to access the content in the website sir. It says 404 ERROR what to be done Please reply

can i use one battery only for arduino and the other only for motors?

Thank you.

MS5611 - How many meter can hold altitude?. It can hold in the 30 or 40 to 100 meter?.

Thumbs up.

can you calculate average time of 1 mesure of altitude ?

Can I use an bmp180 or BMP 280 instead of 5611

GREAT!

Sir i want to know when yiu will release code

Can I purchase the MS5611 case from you?

if im using ultrasonic sensor instead of the barometer how do i change the code ?

👍👍👍👍

Error 2 - Program loop exceeded what should i do?

How about PID Altitude Tuning?

uint8_t max numbers of likes

Make a ai for camera to detect people and use it in drone

now just one more to go gps hold