Thermal Tweeter is hacked together from a SparkFun thermal printer and the web platform internet development board. No computers are used to query twitter or run the printer, this is a 100% stand-alone Twitter appliance.
Keep reading to find out how it works. Read the original version of this article at Dangerous Prototypes.
You tweet, the web platform contacts Twitter and grabs the newest tweets, the tweets are formatted and output to the printer.
Is this wasteful? You bet. And the thermal chemicals on the paper may cause cancer - don't eat it! Thermal Tweeter is an homage to the waste generated by checkout receipts. Unlike a store checkout where you always get a receipt, you're in charge of the Twitter waste. Save the earth, don't Tweet. Or not.
Thermal Tweeter builds on our previous interactive internet projects like the @tweet_tree and internet graffiti wall.
Note: we noticed that Twitter sometimes excludes people from our feed. You can check here [JSON text] to see if your tweet was included. If not, just send it again, we've got tons of paper!
Step 1: Hardware
A serial port assigned to pin IO7 on the web platform outputs serial data to the printer RX pin at 19200bps. See the web platform intro article for more about assigning hardware peripherals with peripheral pin select. See SparkFun's Arduino code and the printer datasheet for the simple control commands.
The printer requires a beefy 5volt power supply for the heating element (1.5A+). We used a 1.5A 5volt wall wort power adapter.
The web platform can be powered from USB or a wall wort. Our best wall wort is powering the printer, and we want to use the web platform USB connection for debugging info, so we used the USB supply. USB connection is only for power and debugging info, it doesn't contribute anything to the Twitter printer.