{"id":14467,"date":"2017-10-28T14:14:50","date_gmt":"2017-10-28T18:14:50","guid":{"rendered":"http:\/\/scruss.com\/blog\/?p=14467"},"modified":"2020-04-10T08:56:22","modified_gmt":"2020-04-10T12:56:22","slug":"teensy-usb-keypad","status":"publish","type":"post","link":"https:\/\/scruss.com\/blog\/2017\/10\/28\/teensy-usb-keypad\/","title":{"rendered":"Teensy USB Keypad"},"content":{"rendered":"
\"\"<\/a>
in which I finally learn about Fritzing’s wire alignment facility \u00e2\u20ac\u00a6<\/figcaption><\/figure>\n

I’ve had a couple of Teensy<\/a> boards for a while, but a misunderstanding that they needed a load of of extra software installed (they need one thing, and it’s easy) had kept me away. They’ve got really impressive specs, and they’re especially easy to turn into USB devices like keyboards.<\/p>\n

\"\"<\/a>
Super-heavy CEECO keypad<\/figcaption><\/figure>\n

Here’s a little demo that turns a phone keypad \u00e2\u20ac\u201d in my case, a ridiculously solid CEECO<\/a> solid metal keypad designed for institutional use \u00e2\u20ac\u201d into a simple USB keyboard. Plug it into any machine (including a Raspberry Pi) and it will be identified as a keyboard. No drivers are required.<\/p>\n

The code is based on the standard Arduino Keypad<\/a> library basic demo. That code was meant for a different keypad, so I eventually found a configuration that worked in the Sparkfun 12 button keypad<\/a> datasheet<\/a>. Rather than printing characters to the serial port, I used calls to Teensy’s USB Keyboard<\/a> library instead.<\/p>\n

The pinout is (from left to right, key side up):<\/p>\n

    \n
  1. do not connect<\/li>\n
  2. Column 2<\/li>\n
  3. Row 1<\/li>\n
  4. Column 1<\/li>\n
  5. Row 4<\/li>\n
  6. Column 3<\/li>\n
  7. Row 3<\/li>\n
  8. Row 2<\/li>\n
  9. n\/c<\/li>\n<\/ol>\n