Sensors - BeagleBone - page 102

Solution
Connect the switch to a GPIO pin and use BoneScript pinMode() and
attachInterrupt() functions.
To make this recipe, you will need:
▪ Breadboard and jumper wires (see “Prototyping Equipment” )
▪ Pushbutton switch (see “Miscellaneous” )
▪ Magnetic reed switch (optional, see “Miscellaneous” )
You can wire up either a pushbutton, a magnetic reed switch, or both on the Bone, as
shown in Figure 2-5 .
Figure 2-5. Diagram for wiring a pushbutton and magnetic reed switch input
The code in Example 2-1 reads GPIO port P9_42 , which is attached to the pushbutton.
Example 2-1. Monitoring a pushbutton using a callback function (pushbutton.js)
#!/usr/bin/env node
var b = require ( 'bonescript' );
var button = 'P9_42' ;
b . pinMode ( button , b . INPUT , 7 , 'pulldown' , 'fast' , doAttach );
function doAttach ( x ) {
if ( x . err ) {
console . log ( 'x.err = ' + x . err );