I was really annoyed by the old-fashioned 7-segment buzzer - really small and horrible looking display. I wanted something cool.

Short demo video


The hardware consists of these little LED modules (16x32 LEDs each one):

Leds are connected into a matrix - in reality only one line of the display shines. I use two or three of these modules. I have actually made two designs - one is in my room (3 modules) and the second one is in my office at work (2 modules).

I also wanted to try China PCB manufacturer. I have found ITEAD studio (https://www.itead.cc/open-pcb/pcb-prototyping/2layer-green-pcb-5cm-x-10cm-max.html) - They made 10pcs of this design for about 20$ + shipping - really cheap and quality is also really good.

The control board PCB is homemade by direct toner transfer method (version for 3 LED modules):

Here is a picture with design version 2 - just two LED modules (the LED in right-down corner means the device is succesfully connected to a wifi.

The first version has only DCF receiver for time synchronization. The second version has also ESP8826 wifi module for internet connection - the time synchronization is via NTP from the internet. The second version has also basic menu for wifi setting and many other features.

The github actual commit contains the version 2 with hardware design and firmware as well. Firmware can be easily adjusted to use more or less LED modules.

Plans for the future

  • Day time / night time swtiching according ambient light sensed by a photoresistor (Firmware is almost ready - not tested yet. Sensor is not physically mounted). Current state - day time / night time is set in the menu manually.
  • 3D printed box - after I finish my first 3D printer ;)
  • After I run out of LED PCBs I will redesign matrix - single line jumpers on both sides. It will be mechanically more resistent and easier to build. I realized this fact just few minutes after I had sent the PCBs to production. It was not possible to pull it back any more.