Rik's Ramblings

Monday, August 08, 2016

Tessel coding

Like I said, I have been playing with my Tessel. Here's some code I wrote to mess with the GPIO port that sits atop the Tessel.

Here's what the GPIO connector looks like.

Click for fullsize image.

The pins labels can be seen in the silkscreen: GPIO - G3, G2, and G1 from the bottom right. Power - GND and 3.3V at the bottom left.

Note in the code below that there is a special tessel module, included via node (require("tessel")). Thisallows you to interact with the GPIO on the Tessel.

Here I use the GPIO property (tessel.port['GPIO']) to access G1, G2 and G3.

 "use strict";

 var tessel = require("tessel");
 var gpio = tessel.port['GPIO'];

 var Button = require("../tessel/button");
 var Led = require("../tessel/led");

 var led = Led.create(gpio.pin['G2']);
 var flasher = Led.createFlasher(led);

 var leftBtn = Button.create(gpio.pin['G1'], ["down", "up"]);
 var rightBtn = Button.create(gpio.pin['G3'], ["up", "down"]);

 leftBtn.onChange = function(evt){
  console.log("left button: ", evt.detail);
  if ("down" === evt.detail) {
   console.log("Do something with left button...");


 rightBtn.onChange = function(evt){
  console.log("right button: ", evt.detail);
  if ("down" === evt.detail){
  else {



I built a daughter board to plug into the GPIO connector. The board contains two buttons, one of the buttons has an LED built into it.

Here are the two other modules I that this one includes, just for reference. They are actually the ones that do all the real work.

Look at all that beautiful Javascript, being used to control a microcontroller. All is well with the world! Of course, I'm not sure how long the code will execute before it generates some kind of memory fault!

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