Green Light Go, Red Light Come Back Later

LED IM status indicator

Depending on your taste for social interaction and tolerance for distraction, an open floor plan or “bullpen” office might not be so bad with a total of four people. user [fiddlythings] likes it, but people often stop by to see him or one of his coworkers only to find them busy or absent. While their status is something they could plainly see in Microsoft Communicator from their own desk, some people like to chat in person or stop by on their way to and from meetings.

In order to save these visitors a few seconds, [fiddlythings] came up with an IM status indicator using their existing nameplates outside the door. Each of their names has a little silver dot by it which he backlit with a flattish RGB LED. These LEDs are driven by a Raspberry Pi and NPN transistors through a ribbon cable.

The plan was to imitate the Communicator status colors of green for available, red for busy, and yellow for away. [fiddlythings] dialed up a lovely shade of amber for away using a mix of red and green. Since he really only needs two colors, he’s using eight NPN transistors instead of twelve. The quick ‘n dirty proof of concept version used Python and a Pidgin IM console client called Finch. Once he got IT’s blessing, he implemented the final version in C++ using Libpurple to interface with Communicator.

This isn’t the first time we’ve seen a Pi used to indicate status—remember this mobile hackerspace indicator?

19 thoughts on “Green Light Go, Red Light Come Back Later

  1. When having four LED lights doing something so basic costs about $50, you know something is very wrong. Internet of things will not happen until there’s a cheap way to do it. Gotta cut it by a factor of at least 10.

          1. Deepening on what voltage the LEDs need, you could probably use an old wall wart laying around. As far as Ethernet goers, low speed (10/100M) spare Ethernet is abundant in many offices I have been to so that could easily be free.

      1. If that program was running from a desktop with a serial port or two, you could use the EIA-232 handshake pins to drive those LED. The output voltage is either positive or negative with respect to ground, so driving dual colour LED is easy. Cheap USB serial ports can be used for expansion.

    1. A cheap way for IoT is to have a Pi as central node and all others as dumber things. In that way a node with a nrf module, simple micro + 4 ws2812 leds should cost less than 3.

      If you want it independent, a 20ish router could drive the leds and have wireless connection.

  2. This reminds me of my embedded systems classes: Use a $400 embedded board to flash some LED’s.

    Engineering: Spending shitloads of money to do relatively little. ;)

    I like the idea, but I agree that the implementation could have been greatly simplified.

  3. While I would personally go for something more like Kendall14’s solution I don’t think $50 is TOO bad. It’s not that long ago the most accessible micros to non-professionals was a > $100 BASIC stamp!

  4. An Electric Imp with a carrier board could do it for about 40$ and not needing SD-card nor a regulated psu.
    A barebones CC3000/ENC28J60 could probaly send that to 20$ if you dont include development costs and respins of the custom PCB.

  5. LOL at more of the 20/20 hindsight in Hackaday comments, I’m to opposed to offering alternatives, but… Does well for everyone not to forget no single person knows everything there is to know about everything. DIY potentially can cut costs, but custom generally increases the cost. Even the time spent trying to research for less expensive ways to do something costs. Most of us say screw it, and accomplish what they want to accomplish the best way they can, otherwise nothing would get done. Noe a days with the wonderful self publishing on the WWW we get to see what a print publication my have rejected, and discuss easily.

  6. I take it that John, Manoj, and Jim don’t have a facebook or any other identity on the web. I first thought that a laser or soldering iron messed up that nice label.

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