PI Face Digital

This package contains a nodejs library and command line tool for the pifacedigital board. As long as the user is in the group spi this module does not need any root privileges.

Installation

On a fresh Raspbian installation you should enable SPI. Therefor start raspi-config and enable SPI under "Advanced Options".

After rebooting you should add your user to the SPI-Group:

usermod -a -G spi pi

Install necessary libraries

git clone https://github.com/piface/libmcp23s17.git
cd libmcp23s17/
make
sudo make install

git clone https://github.com/piface/libpifacedigital.git
cd libpifacedigital/
make
sudo make install

Install node-pifacedigital

npm install node-pifacedigital -g

Using

You can use node-pifacedigital as commandline tool or library.

Commandline

Setting output value:

pifacedigital --type set --pin 1 --value 1

Getting input value:

pifacedigital --type get --pin 1

Watch input values:

pifacedigital --type watch --pin 1

Library

Constructor

The constructor of PIFaceDigital takes two arguments. HW_ADDR the address of your board (setted via jumper) and the optional closeOnExit if true all output pins will reset to 0 if the node process receives the exit signal.

var PIFD = require('node-pifacedigital');
var pi = new PIFD.PIFaceDigital(0,true);

You can set the value of on of the output pins with:

var value = 1;
pi.set(pin,value);

You can read the input pin value with:

var val = pi.get(pin);

or all input values at once:

var val = pi.getInput();

You can watch changes on a single Input-Pin with:

var callback = function(pin,type){
  // Type will be 'lohi' or 'hilo'.
};
pi.watch(pin,callback);