[Bluetooth 5.0 Accelerometer+Inclinometer] WT901BLECL MPU9250 High-Precision 9-axis Gyroscope+Angle(XY 0.2° Accuracy)+Magnetometer Compass with Kalman Filter, Low-Power 3-axis AHRS IMU Tilt Sensor

I had problems with the first unit I purchased. I followed the manual provided but I could not get it to work. Also, the software on the company website included source code examples for Windows but only the compiled apps for android, not source code examples. So I sent and email to the company contact, asking for source code examples for android. The reply was almost immediate, very helpful and polite, with a link to download the code samples. I then wrote again regarding the issues I was having with the device not connecting neither via USB nor BlueTooth. Again, the reply was immediate, and we went back and forth before reaching the conclusion that the device was defective (I was worried it was a compatibility issue with an old BlueTooth 4 device, but that was not the issue). I asked Amazon for a replacement which arrived promptly and is working perfectly. So overall, although I had some issues, the customer support was outstanding and solved all of them. As for the device, it does what it says it does, and well. As for the worries indicated in another review: I agree, the documentation could be better and more clear, but it is clear enough. As for the app not being on Google Play, I believe the app is an example, not a commercial application. This is a sensor to be used in custom solutions/applications, the software is just to show its capabilities. But it is not spyware not does it contain viruses (I have a very strong protection system with 3 different scanners and no one found anything). Actually, the code package downloaded from the company web site even includes firmware code and PCB layout, so actually it seems that rather than trying to steal the customer's intellectual property they are making their own available to their customers!

## Technical Details - Product: WT901BLECL MPU9250 - Interface: Bluetooth BLE - Issue: Gyroscope unit oscillation (rad/s ↔ deg/s) - Reproducible: Yes, every session shows oscillations - Firmware: [check your version] - Tested on: iOS 18.6.2, iPhone ## Recommendation **DO NOT BUY** if you need reliable data. Spend the extra $20-40 for: - MetaMotionR by mbientlab - Movesense sensor - Adafruit BNO085 For hobby projects where precision doesn't matter, this might work. For anything serious, the unit oscillation bug makes this sensor garbage.

Got this for my daughter to use in a science experiment. It connected to both our Android phones and older cheap low-power model and a much higher end model. It did this very quickly and very easily. You need the app or to use PC software to actually visualize and record any information coming off the device unlike an older larger and much less capable accelerometer I used to have which would save text files in its on board memory. I believe this system is much better. We have not tried hooking it up to PC computers yet because that process looks much more involved in the app connection to phone to less than a minute. Recording and sharing the data stream from the phone is also pretty easy but it could use a little bit of improvement. Currently files are only available to be transferred off the phone by accessing them one at a time with the built-in file previewer and then hitting the share button and saving them out to a service like Google drive or OneDrive. This works but it would be better if there were a way to select the multiple saved files and export them all at once. Newer versions of Android do not allow the app to save these files in a commonly available folder such as downloads so using a file manager or plugging the phone into a computer via USB doesn't let you access the saved data files. In early testing the device appears to work perfectly well for the intended purpose.

The Wit Motion WT901BLECL solved a perplexing problem. Purchasing was easy via Amazon, delivery was quick. I had several start up problems, promptly solved by Tech Support. Most importantly "Lucy" was professional, knowledgeable and great to work with. She downloaded the correct app with instructions. "Lucy" was patient and understood my questions. I needed instruction and Lucy provided insight. The device worked efficiently, at a good price and Tech Support is 5 Star. Thank You !!

Got this to record some roller coaster acceleration data. Long story short, if you're willing to spend some time putting external software visualization together, it's great. The Good: * Quick and easy to setup and use, no issues with the app. All of the axes looked great out of the box. * Very high precision in all measurements based on my observation. * Data can be exported to a few different formats to make use of in your own way. * Compact and easy to integrate or mount on your body Why I gave it a mixed review: * After a few uses one of the axes began to skew and it needed recalibration. It's not difficult to do, and perhaps it only needed to be done once, but I didn't want a product that may require recalibration often. Once in a while, but not after a couple of uses. I also found it odd that a device that went through QA check needed calibration out of the box, but maybe it's due to magnetic field variation. That only made me wonder, if it needs such calibration often. That's fine, just annoying. * The PC software is functional, but seemingly not useful except to show a proof of concept. * You can see the data, but there didn't appear an (obvious or easy) way to export the visual data as a video file. I'd rather not have to create or use separate tools to generate visual overlays, but that would seem the best approach with this product. * The best way to use this would be to simply export the raw data and import it into software tools of your own design It's possible I missed some tools in the software, it just wasn't apparent.

Once I got this working it was pretty good. The manual is fairly complete but the translation is rough. One important note. Android now requires location permission to pair to Bluetooth. This only makes sense in the mind of a Google engineer, but the "logic" goes like this. To pair you need the address, and if you have the address you can theoretically get the location from some big database that knows where every Bluetooth device is. So now you have to explicitly grant the permission in order to get the app to work, which makes your private information less secure. None of this is the fault of the device maker, though. Just remember, without location permission the device may reject pairing if you have a recent version of Android. Support email drew a response within minutes.

I've been thinking of making a super-simple dynamic wheel balancer. There is no simple way to read the torque and display the waves on the screen until now. With only one of these gadgets, I can display the angular speeds of the yaw or rotation along the vertical axis. The best signal for wheel balancing purposes is angle speed, not angle itself or accelerations.

After working with this sensor, I learned that it does not have an onboard clock. Observations are timestamped according to the point at which they are received on the device receiving data over bluetooth. This is influenced by transmission lags and load on the device, meaning that there are large variations in the timestamps, and it is not possible to reliably relate them to clock time. I was informed by Witmotion support that another of their devices does have an onboard clock. It is not sold on Amazon, so I went to their website and ordered one. What they shipped me was a sensor with a different part number than what I ordered. They refused to replace it with the sensor I ordered, claiming that I somehow selected the wrong sensor even though *I clicked on a “buy now” link for the exact part number they gave me* and received a purchase confirmation for that number. I recommend staying away from this company! Update: I got a reply to this review asking me to contact the company via Amazon seller feedback. I did so, and they haven't replied. WitMotion I am willing to change this review if you send me the sensor I ordered. I will be happy to return the one I didn't order.