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J. Elfring (p) ba628fc65b Simpler serial read
With chars instead of strings.
2019-09-02 12:22:25 +02:00
annunciatorServer Fix serial port setup 2019-09-02 12:21:14 +02:00
checkLedPins first commit 2019-09-01 00:52:57 +02:00
led-annunciator Simpler serial read 2019-09-02 12:22:25 +02:00
README.md first commit 2019-09-01 00:52:57 +02:00


LED Annunciator

A quick and dirty little device to inform people you are on the phone or in an appointment with a traffic light. The state information are generated by a groupware or messaging application that writes a single letter code into a file.

Command Meaning
a Turn on all leds
0 Turn off all leds
r Switch to the red line
g Switch to the green line
y Switch to the yellow line

AnnunciatorServer takes the code and sends it via serial port to the device. Alternatively, similar commands can be send by an infrared remote control.


An Arduino Nano with nine leds on pins D02 - D10. The leds are arranged in three rows (red, yellow, green) of three leds each. A YS1838B infrared receiver is connected to D11 and sits on top facing backwards.



The Arduino code.


A program to check the led/pin mapping by turning them on one by one.


The shell script that checks a commandfile and sends single-character commands to the serial port. This is useful when the commandfile needs to sit on a network share.

Room for improvements

  • Sometimes the ir receiver starts to send random codes
  • As all leds are connected individually, many more commands can be defined.