Which hardware (MCU, gyroscope, BT) is used in smart rings? I would like to make my own smart ring for fall detection.

 

Start with raising a billion dollars or so for a fab....

 

In case anyone wants to know what is the topic of discussion, watch this.




https://www.indiegogo.com/projects/ring-one-the-most-advanced-smart-ring-for-you#/

 

In case anyone wants to know what is the top of discussion, watch this.

View attachment 305291

It doesn't have fall detection.

I am good in 8/32bits Microchip MCU's programming and assume to use AI and Machine Learning. But I may use STM32WB15CC (320k/48k) in WLCSP 49 3.3x3.4x0.6 P 0.4 mm with Bosch BMG250 (2.5 x 3.0mm) Low noise, low power triaxial gyroscope.

 

It doesn't have fall detection.

I am good in 8/32bits Microchip MCU's programming and assume to use AI and Machine Learning. But I may use STM32WB15CC (320k/48k) in WLCSP 49 3.3x3.4x0.6 P 0.4 mm with Bosch BMG250 (2.5 x 3.0mm) Low noise, low power triaxial gyroscope.

Good luck finding the BMG250. They are obsolete by Bosch. I've used several of their IMU products but it seems they are leaving the market.
https://www.sparkfun.com/products/18799 A CLICK with the BMA490L.
https://forum.allaboutcircuits.com/...controller-and-sensor-node-for-canbus.189388/

My latest IMU project used a PIC32MK with the BNO086 which is a former Bosch product now made by CEVA. It works very nicely but the device firmware is not directly register based. It uses a middle-ware level for most application functions but does have a simplified UART interface.
https://www.ceva-dsp.com/wp-content/uploads/2019/10/SH-2-Reference-Manual.pdf
https://forum.allaboutcircuits.com/...tter-for-this-application.193257/post-1816822

 

Good luck finding the BMG250. They are obsolete by Bosch. I've used several of their IMU products but it seems they are leaving the market.

My latest IMU project used a PIC32MK with the BNO086 which is a former Bosch product now made by CEVA. It works very nicely but the device firmware is not directly register based. It uses a middle-ware level for most application functions but does have a simplified UART interface.

I did the same a few years ago with Arduino Pro Mini ATMega328P 3.3V and 6DOF MPU-6050 3 Axis Gyro With Accelerometer Sensor Module For Arduino. See MPU6050 Orientation Tracking – 3D Visualization .

 

I just looked at another Bosch imu project. The BMX160 has built-in free-fall detection using a interrupt. A nice Bosch chip that's also off market but can still be found.
https://forum.allaboutcircuits.com/...2210-on-linux-with-libusb.179080/post-1691118

 

That expensive ring might track your health but do nothing about it. Then you die.
My body tracks my health then my medications make suitable adjustments to my health.
When I exercise, my heart rate automatically speeds up. When I rest, my heart rate automatically slows down.

 

I did the same a few years ago with Arduino Pro Mini ATMega328P 3.3V and 6DOF MPU-6050 3 Axis Gyro With Accelerometer Sensor Module For Arduino. See MPU6050 Orientation Tracking – 3D Visualization .

Great! Experience makes it easier. What exactly do you want to build? For a practical device a good set of hardware/software requirements is a must have.

Parallax LSM9DS1 9-axis IMU (accelerometer interrupts for detecting freefall)
https://forum.allaboutcircuits.com/threads/pic32mk-mc-qei-example.150351/page-2#post-1559735

Building a ring sized unit from scratch (chip level PCB design and programming) would be a lot more fun.

https://forum.allaboutcircuits.com/threads/accelerometer-vs-pressure-sensor.187911/post-1746984
Drop testing for free-fall detection with the BMX160 IMU.

The tiny chip between the pin header and the USB socket is a BMX160 IMU.
https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmx160-ds0001.pdf


The yellow line is the Z axis. You can easily see the pull of gravity and handling movement, release acceleration, free-fall (Z goes to zero) when dropped and the impact from just a couple of feet drop to the seat of the chair.
https://peer.asee.org/newton-s-law-and-accelerometer-integration-applied-to-impact-analysis.pdf
https://ntrs.nasa.gov/api/citations/19970034695/downloads/19970034695.pdf

Data point update every ~6ms.

1-55 1G -> falling at 9.8m/s
https://www.phidgets.com/docs/Accelerometer_Primer#:~:text=On the earth's surface an,sensor in a particular direction.

Accelerometers measure acceleration. As such, you might expect an accelerometer to measure the acceleration of the sensor relative to the space around it, and that if the sensor is standing still it should read 0g. This is not entirely accurate. On the earth’s surface an accelerometer that’s not moving will register a reading of 1G (9.81m/s), straight upwards. So what’s going on here? Accelerometers work by measuring the movements of small internal structures caused by accelerating the sensor in a particular direction. When an accelerometer is stationary on earth’s surface, the sensing part of the accelerometer (as with everything else) wants to fall at 1G towards the centre of the earth. However, it is being held up by the casing of the accelerometer by an equivalent 1G in the other direction. Thus, the equivalent measured acceleration is 1G away from the ground. The only time an accelerometer will register 0G in all directions is if it is in freefall in a vacuum.

55-73 was the release and drop acceleration.
73-103 was free-fall post drop acceleration to zero G reading.
https://physics.stackexchange.com/q...lerometer-shows-zero-force-while-in-free-fall
103-115 was the impact with the chair seat
115 - impact decay (bounce)

 

That expensive ring might track your health but do nothing about it. Then you die.
My body tracks my health then my medications make suitable adjustments to my health.
When I exercise, my heart rate automatically speeds up. When I rest, my heart rate automatically slows down.

Thanks Captain Obvious.

 

Great! Experience makes it easier. What exactly do you want to build? For a practical device a good set of hardware/software requirements is a must have.

Building a ring sized unit from scratch (chip level PCB design and programming) would be a lot more fun.

I am not a beginner. Hardware and software design is no problem for me.

For example, working prototype of GPS/LoRa Micro Cat Tracker embedded in a cat collar (PCB width 12 mm). The problem was just that build in SONY GPS in S76G chip had not sufficient sensitivity to process GPS wire dipole antenna signal. Although I designed and built the 40 dB GPS amplifier, I am now testing u-Blox MIA-M10Q GPS Receiver controlled by ATSAMR34 MCU/LoRa.

 

I am not a beginner. Hardware and software design is no problem for me.

For example, working prototype of GPS/LoRa Micro Cat Tracker embedded in a cat collar (PCB width 12 mm). The problem was just that build in SONY GPS in S76G chip had not sufficient sensitivity to process GPS wire dipole antenna signal. Although I designed and built the 40 dB GPS amplifier, I am now testing u-Blox MIA-M10Q GPS Receiver controlled by ATSAMR34 MCU/LoRa.

OK. We both can handle the job, so what's the actual question about the ring design as the hardware and software design for fall-detection functionality (I've already investigated several methods) are easy. The practical integration into a ring sized practical device seems to be the true issue.

 

OK. We both can handle the job, so what's the actual question about the ring design as the hardware and software design for fall-detection functionality (I've already investigated several methods) are easy. The practical integration into a ring sized practical device seems to be the true issue.

It would help me in my own smart ring design to know, which hardware is used in the Best smart ring 2023: the top sleep tracking and NFC tech at your fingertips.

 

 

Pretty close to what I thought. Standard SMD stuff in a ring sized and shaped package. Knowing that doesn't help much to integrate the parts into a usable product.

 

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Perfect and thank you. That is I was looking for.