Posture Pack WFH

wearable posture sensing with bluetooth module

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My DIY version of a posture sensing wearable. I think this project is a great entry for: 'Refresh Work-From-Home Life'. It addresses workspace ergonomics specifically as a way for users to receive real time feedback on the device they're actively working on. It's intended to improve a users posture by providing feedback via bluetooth when slouching is detected.

It's been designed to be worn in a pocket sewn onto the back of an undershirt.

This device contains

- A BN0055 9DOF IMU to measure users posture
- ATmega32U4 operating at 3.3V and 8MHz
- Adafruit BLE UART module for bluetooth communication
- 500mAh LiPo battery

I'm using the free Light Blue app to receive notifications from the device. Instructions to connect below.

I know products exist with similar functionality but I decided to build one myself for the fun of it.

I was happy with the final functionality and repeatability of the measurement output by the BN0055.

I had the board manufactured at

All the components were ordered from DigiKey.

I used a toaster/reflow oven to surface mount the components.

I 3d printed a case, I had to divide the case into multiple parts as I have a very small print bed.

I did not break out the ICSP pins to headers/connector on the attached PCB files, this means I had to solder jumper wires directly onto the ATmega32U4 to upload the bootloader.

h - 3.15 kB - 07/09/2021 at 03:20


ino - 6.13 kB - 07/09/2021 at 03:20


  • Rev2 Design update.

    ImageryEel10/04/2021 at 20:02 0 comments

    Just wanted to post and mention I am working on another revision of this with a haptic feedback motor which should allow this to be used without bluetooth if necessary/more convenient. When I was testing this I often wanted to have a simpler feedback mechanism. 

  • Action Gif

    ImageryEel07/09/2021 at 03:24 0 comments

  • Video Log

    ImageryEel07/09/2021 at 03:21 0 comments

    Quick video showing the process I used to create the posture pack:

View all 3 project logs

  • 1
    Uploading bootloader/ino file

    I used a teensy 3.2 to flash the bootloader via ICSP.  See attached image for connections.

    Install pro micro library as described:, select teensy port, Change board to ‘pro micro’, Programmer: ‘Arduino as ISP’, now you can flash the bootloader and you can upload a sketch by selecting  ‘upload using programmer’.

  • 2
    Making a pocket

    I'm not a experience tailor so I won't offer detailed instructions for the pocket, however I did use these shirts:

    They were long enough for me that I could cut off the bottom 15cm or so and use that to create a pocket as shown in the image.

  • 3
    Basic use of the Posture Pack

    There are three modes for the sensor, 

    1) Acceptable posture ( >70 based on my measurements and testing)

    2) Below threshold, user receives 'You're Hunching!' notification followed by measured posture

    3) Sensor is placed on flat surface, outputs current posture, average angle, number of samples and firmware version (sample output below shows current angle -12, average: 75, samples 1662 and version 7.

View all 3 instructions

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