Physical Reddit message indicator


The indicator in action

You’ve got mail!


Any “normal” person would look at a project like this and wonder why you would go to such lengths for something seemingly trivial, to which the hacker would simply reply, “because I could.” With that mentality, I give you a physical desk indicator for new Reddit messages.

The Body

I scavenged some potential project boxes at a thrift store for under $10 USD and ended up liking the clock best, so I landed on using it for the body. I hollowed the clock body out in order to make room for my parts & took care when removing the glass plate and gold lip.


Clock original

The original clock

Clock body, hollowed out

Clock body, hollowed out


The Arduino

This was the primary reason for this project, as I’ve recently gotten into microcontrollers and low voltage electronics. I figured you can do almost anything with an Arduino, so long as you can picture it in your head what you want to accomplish. I used an Arduino Uno, three LED lights with inline resistors & a 1/4 watt speaker for sound. I used some sandpaper to rough up the LED surfaces and diffuse the light better inside the envelope. You can find the source code below as well as a pinout diagram.


Trying to get the wiring set up correctly

Trying to get the wiring set up correctly

The computer

The computer is really the engine driving this, because without the ability to poll Reddit for new messages, this desk trinket is little better than a paper weight. Using curl and wget I was able to log into Reddit & pull the JSON info from the specified user’s page. This contains their unread messages variable, which was simple enough to sort through using a REGEX command (all hail Perl — king of the pattern match!) If you know even a little Perl you should have no trouble at all understanding this simple scraper. If it finds the right stuff  from the JSON data, it sends a specific set of commands via serial to the Arduino, flipping the switch to activate its “melody” and start looping its “glow” function. This will repeat every time the number of unread messages changes (essentially, increments since you have to read all new messages at once.)


Version 2.0

I had a lot of fun putting this together. My plans to improve on it are detailed in the video, but essentially I’d like to add an ethernet shield to the Arduino so that it isn’t dependent on being connected to a computer via serial. Perhaps you could put this in your living room next to your photos & run ethernet (PoE hack?!) to it & you can always tell if someone is trying to get your attention on Reddit! Happy hacking!



Files, Source Code, and Notes

This was compiled on the Arduino ALPHA 0023 binaries, so if you have trouble compiling the sketch, try using that version instead. Sorry, I know I should be using up to date software.

Arduino source code for the project


Perl script for the project. Rename to PL extension to be proper.

Arduino Reddit Reader pinout

Arduino Reddit Reader pinout

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6 Responses to “Physical Reddit message indicator”

  1. IronRectangle Says:


    “You can find the source code as well as a pinout diagram .”

    Reddit is BEGGING for this info! Great hack, thanks for sharing.

  2. Loldudester Says:

    You should add a few 7 segment displays so it can tell you how many messages you have!

  3. Jooniar Says:

    Hey Brad,

    I think your idea is awesome and has inspired me to do something similar except I want to monitor my hotmail, gmail and reddit inboxes simultaneously. I’m only good with visual basic and the arduino seems to be C++ or some variant.

    How would I go about monitoring the other services?

    Feel free to PM me using my reddit handle “Jooniar” and thanks for any help.

  4. 20 Arduino projects of 2012 | Nudatech Says:

    [...] This project could be useful to all the Reddit users, it’s a small desk notifier that lights up when your Reddit account receives a message. Project page. [...]

  5. Nudatech Says:


    I wanted to let you know your Arduino project has been added to a list of 20 Arduino projects of 2012 published on Nudatech’s blog ( ).

    Please let me know if there’s any mistake in the short note I wrote about it and if the link I chose for it is the right one.
    Obviously sharing the list on social networks, blogs and forums is also appreciated :-)


  6. Hale Knox Says:

    I can’t seem to get the program to work… Any tips?

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