Project rebuilt

This project has been rebuilt into Lync presence (busy) light with navigation LEDs.

Lync presence light, green LED
Green LED lit on the Lync status light.

When I am at work, I use headphones; a lot. About half the time I am listening to music, the other half I am talking with someone on Lync (Skype for Business). This has made it difficult for my colleagues to know whether I am available or not, so I get interrupted when I’m on the phone. I needed a way to communicate my availability, and Lync already does a pretty good job with this; it’s red when I am in a meeting, on the phone or simple do not want to be disturbed. Yellow when I’m away; I don’t think the away part is a problem, when my chair is empty I am usually away… And green: come on in! Enter the Lync presence light, or busy light if you will. Yeah there are some you can buy, but where is the fun in that? So I made one using an Arduino board.

Table of content


LEDs connected inside Lync light
Inside the Lync light, LEDs connected to the Arduino board.


I used three LEDs, but you can use an RGB LED instead. Each LED has a resistor in series, the size of this resistor depends on the LED. I used 100 and 150 ohms. The outputs on the Arduino has a maximum current of 40 mA, now that is the absolute maximum, so it’s best to stay a bit lower than that. A typical LED is 20 mA, so that is no problem. But if you want to drive bigger, more powerful LEDs you will need a transistor between your Arduino and LED. Another thing to keep in mind is that the total current on all output pins must not exceed 200mA, but not a problem for our three 20mA LEDs.


As long as the total current is below 400mA the Arduino can be powered by the USB connection. This is perfect for our device, as it has to be connected to the computer anyways. One less wire, and adapter, to worry about :)

Lync presence light, in use on desk
Lync status light ready and in use on desk, greens means available :)


Now; we need to let this device know about our Lync status somehow… Otherwise it’s not going to do much good. Luckily and thanks to the power of open source; someone had done a lot of the job for us already. I found a project on GitHub that used a blink(1) to show the Lync status. This made my task a lot easier, I love open source! You can find the Arduino code and Lync bridge software under the source code section.


Output pins

  1. D3 Green LED
  2. D5 Yellow LED
  3. D6 Red LED

I used these output because they are PWM, pulse-width modulated, meaning that the brightness of the LEDs can be controlled. So you can do cool things like softly blink them by fading up and down.

LEDs connected to Arduino I/O pins
Outputs on the Arduino board, connected to the LEDs.

Please leave a comment or tweet if you have any questions or feedback on this project.


Schematic drawing

Lync presence (busy) light circuit
Schematic drawing for Lync presence (busy) light; with Arduino Uno R3.

Source code


Set blink(1) and Arduino light based on Skype for Business or Lync presence state.


0 0 3 C# 2 months ago


Show Lync presence status with three simple LEDs.


0 0 0 Arduino 4 months ago

Image gallery

Parts list

External links

Project: Lync presence (busy) light with 5mm LEDs by Thomas Jensen is licensed under CC BY-SA 4.0 with attribution required.

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  •   Created May 04, 2016
  •   Last modified 5 days ago
  •   Project status: Rebuilt