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  • Writer's pictureDr. Tõnis

Boss Detector


I was contacted from Seeed Studio to make a project with their new XIAO BLE products. I had already had some time in my mind a so-called boss detector project. Several years already one can see in the internet a gif about a device that switches computer active program wehn a boss approaches.

Project summary

I thought about using two BLE boards to make the detector. One is at the door and sends an alarm to the other one that is connected to the PC and acts like a keyboard. If the movement is detected an “Alt-Tab” combination is pressed and the screen switched. Why two BLE devices? The one on the door could act like a Bluetooth keyboard itself. However, what happens when somebody plays with the door or the “boss” is next to you and somebody else is opening the door again. To prevent multiple triggers I thought to add a reset switch to the second one and one could reset it after the air is clear again.

My responsibilities

  • Suitable software development

  • CAD design of the simple housing, 3d printing and assembly


The two used XIAO boards have very good hardware, however the software support is lacking. I was able to show that the advertised XIAO BLE functions work if you find the suitable library. I had difficulties finding suitable working libraries and that was the main limitation for me.

In the end I made 3 different “devices”:

  • Simple one connected with a cable to a PC - USB keyboard

  • Bluetooth sensor that triggers with a button pressing - Bluetooth keyboard

  • Two Bluetooth devices working together

Although the programming was like riding a rollercoaster I learned a lot about BLE and probably would use this communication method for some other future project. Anyway, the proof of concept of the Boss Detector is done.

A little longer journey description: Instructables

Used tools

SW: Fusion 360, Arduino IDE, Circuitpython

HW: 3d printer, XIAO BLE nRF52840, XIAO BLE nRF52840 Sense

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