9-Axis IMU LESSON 5: Calibrating the BNO055 9-axis Inertial Measurement Sensor

[@danielsaenz5570]

Great lesson!! Really enjoying this series of lessons! It's sad how few people watch these videos; they prefer watching silly cat videos. Thanks so much Paul!

[@sneezydanger]

Thanks a lot! I'm studying mechanical engineering and this series helps a lot on my research project on multibody dynamics measurement. Your lessons are well appreciated Paul!

[@jimfisher3372]

Got it. I used trig and was able to program a Tilt sensor around the X axis. Great series.

[@Mystic0Dreamer]

BOOM! Another lesson completed. This is great Paul. I can't thank you enough for making these courses. Love the little plotting program from Hackaday too. I'm all calibrated up. I'm going to leave the algebra up to you because I'm too lazy (ha ha), But I'll definitely watch that lesson next and learn how to do it. I'm sure I could figure it out myself if I had too, but I don't want to hurt my brain right now. (ha ha) So I'll just let you do it and then learn from what you teach. I have other lessons to attend to. I'm learning about a whole lot of different things right now. So I'm off to programming a speech engine.

[@paulmcwhorter]

I am enjoying this series of lessons. I really like the idea of a virtual environment where the objects track what is happening in the real world. To me that is a lot of fun. Thank you for the kind words

[@opalprestonshirley1700]

SOHCAHTOA, now that has been awhile. An excellent video, didn't take but a minute to fully calibrate. Thanks Paul.

[@darshb38]

Thank you Sir. You are Awesome :) . Such video lessons are additionally useful because of covid virus home schooling

[@juanfluxa6517]

Excellent tutorial with very clear explanations. Thanks Paul!

[@paulmcwhorter]

Glad you enjoyed it!

[@Dieselfitter01]

Fantastic information Paul. Always hooked on your content. Thank you for everything you do.

[@bluehornet6752]

Not sure whether or not someone has mentioned this already, but the line at 5:40 is not doing what you think it is. uint8_t system, gyro, accel, mg = 0; That likely doesn't set all those variables to zero, it only sets *mg* to 0. Well, it possibly does...but possibly doesn't. My guess is that it won't, as it doesn't seem to testing it here with avr-g++. Reviewing the compiler's documentation, it appears that *static* variables are in fact initialized to 0, but auto/local variables are not. So you can either put the keyword *static* in front of uint8_t...or just add another line to your above line, to set them all to zero: system = gyro = accel = mg; EDIT: Not sure why KZbin is suddenly inserting two newlines between paragraphs now, requiring you to have to edit the post to fix it.

[@bluehornet6752]

This IMU really takes some time to calibrate, wow. I mean, how would you use it in a serious project if you weren't sure it was actually calibrating each time the power was turned on? That's a bit concerning.

[@jeanmahe8657]

love watching your vids always easy to understand

[@SarkarMotion]

Now every time I hear trigonometry, I will have a smile on my face.

[@jstro-hobbytech]

this is most excellent. i drunk red bull, sugar free

[@gweliver]

Can not wait, very exciting!

[@bkane386]

The windows 64-bit Serial Plotter no longer appears to be available. I have downloaded the 32-bit, but the serial plotter seems to freeze most of the time and especially when trying to plot all 8 lines. Have you found this to be the case? If so, do you have another suggestion?

[@k1jo939]

Thanks for the tutorials. How can I store the calibration data to use it to configure the device later when it is no longer possible to manually rotate the device to calibrate it? I'm a ham radio operator and want to build a device to set my antenna azimuth and elevation for tracking ham satellites.

[@mustafabhadsorawala652]

Hi Paul, I am following your tutorial for a project. But I am running the calibration in a while loop in void setup() - till the acc, gyro and magnetometer reach calibration level 3. Is there a reason to run getCalibration() continuously in void loop() ?

[@jackd6134]

Accel cal readings are a little lower by 0.1 for me. Gravity must be a little less in Arizona than in Texas. ; )

[@NVANAPALLIVENKATASATYAUMASHANK]

Awesome sir... you are very helpful to me to learn Arduino from base.. to some amazing kind of stuff ... Thank you so much SIR ...!!😍😍

[@Каксваритьпельмени-ы4ч]

I calculated the tilt using equation of the line which I learn from your wonderful Arduino series. So when the acceleration is 9.8 then we have 0 tilt and as acceleration decreases we’re going down to -180 degrees. Equation is Tilt=9.34*accZ-91.58

[@Ticdou777]

Thank you for your explanations, but what are exactly the calculations done with the data to do the calibrations on the accelero, gyro and magneto ? You use a function for that but how can we have the details of this function ?

[@NaveenKumar-rx9zk]

Thanks again Paul for imu lessons.

[@rantheone9789]

Hello, Is there a way to close the bno? Like the command begin.bno(), is there something that do the closing when I am not using the bno and want to save battery?? Thank you for your help!

[@TinFoot]

Thank you for the demo of how external objects effect the calibration. For example I could not get 3,3,3,3. Finally, I noticed in your video that the motor effects the calibration. when I moved my BNO055 9-axis Inertial Measurement Sensor away from all wires, magnets, and especially the Huion board, my BNO055 calibrated immediately. Thank you, Thank you , Thank you!

[@usrrsr]

Is it like that calibration data is saved on chip or each time needs to be done

[@quaternion-pi]

You are an awesome, motivational teacher. I am implementing the homework assignment as a matplotlib real time plot. It really would be nice to have a dedicated forum either on your toptechboy website, or something like reddit to actively share ideas . Another suggestion is to consider a github account to put code - others could modify and post their code also with your permission. I don't know where you find all the time to do what you do. Greatly appreciated! Proposed Homework Solution: Using python math library for atan2() since it accounts for quadrant of solution and then converting from radians to degrees: degrees_tilt = math.atan2( acc_Y, acc_Z) * 180/math.pi # acc_Y, acc_Z are the Y and Z acceleration values from the BNO055 acceleration vector

[@paulmcwhorter]

" I don't know where you find all the time to do what you do." Simple . . . I dont own a TV, and dont go to movies. I spend my time DOING not WATCHING. I see the benefit of a forum somewhere, but you might have noticed I turned all commenting off at www.toptechboy.com. The issue is all these new crazy privacy laws, I do not want to open myself up to frivolous litigation over protection of privacy, hence I dont want to host a forum that has user names or passwords. I do enjoy the comments and interactions on youtube comments, and wish we could get a little more of a sense of community among the channel followers. As you know, there is 1 of me, and 100,000 subsribers, so I am not able to look at code people post, or help debug, but do think it would be good if you guys intereacted more among yourself, and help each other out. Thanks!

[@qzorn4440]

Always a wealth of information, such as the plotting software to enhance the Arduino IDE support. A tilt warning alarm to prevent a crash might be good? Thank you, Paul.

[@sushmitapanigrahi5484]

Hello, truly appreciate your lecture series. Have 1 question, how does IMU calibration take place ? what is the science/tech behind it ?

[@IHRNepal]

Hello Sir, i am learning arduino programming by watching your videos. It really helped me but if i have to execute' if ' condition only once then which syntax do i need to follow ? its not about this video but its the latest video so i thought i will get reply here.

[@joshbarron7406]

is there any way to have it calibrate it once and then run a separate code to only pull the data?

[@hello81642]

They say this product is discontinued. What is a suitable replacement?

[@dcpowered]

Great video! Please make more videos on the fantastic IMU! Can you explain how to use the linear acceleration data to find distance moved by IMU?

[@SarkarMotion]

More than 500 views and just 50 likes for this great video. Were it in my control, I would have given 500 likes just for SOH CAH TOA. Cheers!

[@paulmcwhorter]

For some reason it sounds like a extinction level volcano event.

[@SarkarMotion]

@@paulmcwhorter hmm, SOH CAH TOA is the evil brother of Krakatoa

[@ericsmith7988]

Hello, I ran the calibration and it doesn't want to stay in calibration for very long and is hard to recalibrate it. Could my mouse or keyboard be causing the problem? I have noticed that it is very sensitive and when I have it perfectly level my "x" and "y" axis are zero, and my "z" axis stays around "9.65". I have never studied Trig so will watch and study along. Thank you Paul for a great lesson.

[@nathanleopold8972]

Thanks for the tutorials Paul. These are amazing! I'm working through this lesson but I'm running into a two issues. My Gz is not close to 9.8 even after i calibrate. It seems to come in at different values each time too! I ready anywhere from 9.5 to 9.7 after calibration with my breadboard sitting in the same spot. My Gx and Gy are also all over the place. They will be anywhere from +/- 0.2 Doesn't seem like much but when I start trying to get an angle I'm getting 1-3 degrees. Second issue I'm having is with the serial plotter. Are you using any add in software for your plotter? Mine doesn't have any options to turn curves on or off, change the scale from auto, or rename the curves. Sorry if I missed something there. These are great videos and you have a great community here. Thanks Nathan

[@leonardcheri2118]

If I dont want to go through the routine to calibrate sensors espeically the acclerometer. Can I use lets say GPS readings to calibrate? I have an imu and gps in same module. Since gyro and magnetomer calibrates easy.. Im thinking now at least I know where is the x and y and z for my accleration readings and my GPS can just correct that next step in a kalman filter implementation for example. Does it work?

[@Gabriel-iy1zq]

Great video! I have enjoyed every video. I do have a question tho, how long can an IMU stay calibrated? Like, once you complete the calibration process and the system is in lvl 3, how long can it stay there?

[@RithJosef]

Hello teacher, after you calibrate already Dose its save or not ?

[@paulmcwhorter]

Does not save it, unfortunately.

[@wayneswan3092]

I'm sorry, I'm hearing impaired. what kind of trig is that you are saying we need for the homework assignment?

[@nobodyeverybody8437]

Dear Paul, is there any other method (or code/algorithm) that we could use to manually calibrate the signal of any 9-Axis IMU, instead of using .getCalibration() method?

[@mamaigoodgirl]

I don't get it, why I cannot calibrate it shows only Ac, Mg :Partially Calibrated

[@snowflakes003]

in my case, I am getting accelerometer's calibration in no time, but cannot get gyroscope's calibration : - 0.08,0.04,9.6,3,0,3,3

[@eng_zahra1998]

Hello thank you but I need code pleas

[@toddduffett1378]

Please explain how rotating the assembly into various orientations, exposing the Accelerometer to the force of gravity from all angles, translated to exactly 9.8 not 9.7 or 9.9 without the system knowing what the known value is. Did the rotation simply zero the accelerometer by exposing it to all angles as opposed to truly calibrating it? For example, when I calibrate a micrometer or caliper, I use a certified gauge block with traceability to NIST standards. How does the chip know what to associate with the values it reads?

[@paulmcwhorter]

Understand we are doing this as a desktop demo, not an actual navigation device. A lot of the calibration is stuff going on inside the BNO itself. This board is a great learning platform, but I am not at all suggesting it should be used in deployed systems.

[@toddduffett1378]

@@paulmcwhorter Is it possible that the integrated software assumes 9.8?

[@paulmcwhorter]

I think it probably finds the maximum deflextion of the acceleromter, and then assumes 9.8 . . . . i dont think it is actually flat out measuring the acceleration of gravity

[@toddduffett1378]

Coming back to this subject to develop a variable frequency flashing LED that flashes faster with increasing deceleration rates. Oh by the way for anyone giving this a try, be aware that the mag sensor will be negatively impacted if you happen to be using a steel desktop for your worksurface. 😳

[@pudelfan3059]

Hi. First of all, great series of videos. Learning alot. I do however have a question about the calibration. If I put this board on let's say a quad, do I have to go through the calibration process every time I turn the device on? Pudelfan

[@paulmcwhorter]

I would really discourage a DIY quadcopter using this sensor. It has a tendency to lose calibration under different cirucumstances. I dont view quadcopters as good DIY projects because of safety issues.

[@pudelfan3059]

@@paulmcwhorter Hi. Thank you for the quick answer. The quad was just an example. Here in Austria there is a lot of hassle to go through to fly anything weighing more than 250g. But the question still stands. Is the calibration necessary every time the module is turned on? Pudelfan

[@blackboxcameracom]

@@pudelfan3059 The BNO055 has a number of different modes which use the sensors in various combinations. For the IMU modes where the internal microcontroller is fusing the data from the individual sensors to give the output you will need to calibrate the sensor on each power up. The calibration data can be read from the sensor, stored, then reloaded on power up so that the time required for calibration is shortened. However this does not really work very well for the 9DOF mode as the magnetometer does not calibrate that well from the stored data if the sensor is not in the same orientation. For some applications the IMUPLUS mode which uses the accelerometer and the gyro is better as both these sensors calibrate more easily. Without the magnetometer you cannot relate your heading to north, but for many applications your course over ground will come from a GPS anyway. The IMU would be used for stability and measuring rotation when turning.

[@adamsvette]

@@blackboxcameracom Thank you for answering that question. I have the same question, but am now wondering how do I LOAD a calibration into the IMU?

[@billfield8300]

HI Paul.. in an effort to go under the hood, I was hoping to get a definition of the 'uint8_t' variable type. I am more than willing to use it as prescribed but (and no disrespect intended) even if given by God, I still need a way to understand it.. Keep up the good work. Im all in with all 3 series you are currently doing. Thanks for the effort.

[@TinFoot]

I too had this question. I think the following link is a good explanation: stackoverflow.com/questions/14515874/difference-between-int32-int-int32-t-int8-and-int8-t

[@codecage9333]

I can move my IMU around and get all 4 calibration values to read as a 3, but then some times when I set it back down the system value returns to 0(zero)! Some times it might change from 3 to 2 or to 1, but most of the time it seems to go to zero. Any thing you can add would be helpful. When I start moving it again it will go back to 3 after a short time.

[@codecage9333]

I figured it out! I was setting it down on my laptop keyboard! Guessing the electronics in the laptop was messing with the IMU unit. Setting it down on top of my empty ceramic mug, that originally had my HOT coffee in it, and all is fine. Had stopped the video to play around with my calibration right before you brought the stepper motor into the picture! :-)

[@paulmcwhorter]

I dont know how to turn off the automatic continous calibration mode on this sensor. Sometimes in its effort to improve calibration in real time, it actually loses calibration. I have found the auto calibrate 'feature' to be a nuisance that actuallly can make more problems than it solves.

[@terranceparker2015]

@@paulmcwhorter It is in the sensor library...buried.

[@manojentcal]

Hi, Teach!! Wonderful lesson once again. Have been following this series with the latest Arduino Series. Am using the identical hardware as you are. However, am facing a situation with the calibration of the BNO055, as taught in this lesson. After getting a 3 on all four parameters, the calibration is mainatined only so long as I have the Serial Monitor/Plotter on. The moment I turn the Serial Monitor/Plotter off, I lose the calibration. I need to re-calibrate the BNO055. It would be prudent to add, that I am only turning the monitor off and not the device ie the Arduino Nano/BNO055 off, per se. Is this normal? if not, a little help from you or any of the learned friends following this channel would be of great help. Regards.

[@paulmcwhorter]

Turning the serial plotter off resets the arduino, so you have to recalibrate. The BNO055 is also bad about losing calibration if the sensor just sits. So, it is good for learning and benchtop demos, but hard to use in real deployed system.

[@manojentcal]

@@paulmcwhorter Thank you Teach. Really appreaciate the prompt answer. Spent a lot of time surfing the net, wondering whether something was wrong with my module. Thank you again!!

[@signature445]

Sir could you please help how to fetch 1000 samples(accx,accy,accz,gccx,gccy,gccz) in one sec

[@Tosoruth]

Not sure what the deal is but none of my calibration data is showing up in SerialPlot. Settings are the same as last lesson, updated them as we went through this video(Data Format>Number Of Channels:7, etc.) COM is good, calibration works in Serial Monitor. Only thing I'm seeing is a [Warning] Data parsing error for channel: 3 under the Log tab in SerialPlot. Any suggestions would be greatly appreciated. Thanks everyone!

[@paulmcwhorter]

Make sure you are building your string you pass perfectly, not forgetting any commas. Last print should be a println. Check and see if you can pass one value only and graph it.

[@Tosoruth]

@@paulmcwhorter Thank you, Sir. I'll give that a shot. 👌

[@JoeLyddonWWR]

Paul, This is REALLY COOL... but, I still have a problem of how this is going to help me with real problems. ... other than just being an interesting expensive toy... How would I use it around the house? Would I develop a system that I could use in the car while traveling? Doing what? What does IMU mean? It looks like it responds to movements very quickly... Perhaps the system should be shielded to prevent it from being effected by motors & other devices around it? Otherwise, it could not be trusted 100% of the time. Thank you.

[@paulmcwhorter]

You could put it on your head, and track your head position, and then have a camera remotely on a servo pan tilt unit. The camera would move in response your head motion, and you could create a remote reality system. Just one idea.

[@codecage9333]

@@paulmcwhorter Must be how the those gunship pilots look at their target and the guns point to where they are looking!

[@arifemrekocoglu2579]

thanks, dayii

[@JoeLyddonWWR]

Paul, your MIC is still very HOT... I have my system audio level almost to Off and you are coming in Loud & Clear... When set at the normal level, it is BLASTING HIGH... Thank you for turning it down... a lot... :) Glad you got it fixed... from the other day... I think it was a loose plug-in... What was it? Have a good one! Thank you very much.

[@paulmcwhorter]

This video was made before I got the new Yeti microphone. Understand when you give feedback, I already have 50 or 60 videos all made and queued up for release. Hence, you are watching a video made some time ago, and probably will be more coming out with the old microphone

[@mohazez6094]

Dear Mr.Paul I thing it was wrong to said that "the Gravity pull the sensor down" ( at 2.40 min) .according to albert einstein special relativity theorem ,the right thing to say is the spacetime push the sensor down ..this is how the gravity work

[@gweliver]

OK, SOH CAH TOA it is then. I always must review everything it appears, but there are a lot of web-sites when I searched; Trigonometry, Sine, Cosine, Tangent, review

[@bambumbambu]

at first sight, it seems very unstable for a 31 pounds sensor board. even if it has 14 bit precision....

[@Hino_55]

I kinda want to stick to what I got used to in the New Arduino Tutorials... That is, I get obsessive compulsive on the grounds that I want my variable declarations to be at the top of the program (after the #include, if there are any) ...and not do it inside the void loop() For Example: #include #include #include #include . . . uint8_t system,accelerometerCalibration,gyroCalibration,magnetometerCalibration; void setup(){ . . . } void loop(){ system,accelerometerCalibration,gyroCalibration,magnetometerCalibration=0; . . . } I just don't know if that convention will work for this line of command, imu::Vector accelerometerData = myIMU.getVector(Adafruit_BNO055::VECTOR_ACCELEROMETER); I plan on putting the imu::Vector accelerometerData; at the very top of the program (after #include) and put accelerometerData = myIMU.getVector(Adafruit_BNO055::VECTOR_ACCELEROMETER); inside the void loop()... so we remain consistent. ^Will this work Sir Paul?

[@Hino_55]

P.S. Regarding this line that you used Sir Paul: uint8_t accelerometerCalibration,gyroCalibration,magnetometerCalibration,system=0; I find that only the system is set to 0. As I understand, you put a zero such that for every loop, the calibration value resets to 0. Will putting zero in the system variable suffice? I mean would it automatically reset the calibration values of the other three variables to zero as well by doing this? I am thinking if this is the more correct way of doing it: uint8_t accelerometerCalibration=0,gyroCalibration=0,magnetometerCalibration=0,system=0; so that all calibration variables are reset.

[@SarkarMotion]

Always remember kids, when in trouble, uncle SOH CAH TOA will come to the rescue.

[@For_the-love_of_physics]

12:35

[@arifemrekocoglu2579]

Hello, Can you explain me how I can get data from BNO055 on Arduino using UART protocol?

[@jacobdavidcunningham1440]

"yellow or pink cancer packets" lmao

[@paulmcwhorter]

You are the first to comment on that . . . went right past most. I would never use those things.

[@V_Pavlov]

For some reason I get 0.00, 0.00, 0.00 readings on acc.x(), y , z it was not like that a minute ago. What a disaster.