Using an PCF8591 Expander as a Virtual Board (4 Pin Analog Input)

Breadboard for "Expander - PCF8591"


Fritzing diagram: expander-PCF8591.fzz


Run this example from the command line with:

node eg/expander-PCF8591.js
const { Board, Expander, Sensor } = require("johnny-five");
const board = new Board();

board.on("ready", () => {
  const virtual = new Board.Virtual(
    new Expander("PCF8591")

  const sensor = new Sensor({
    pin: "A0",
    board: virtual

  sensor.on("change", value => {
    console.log("Sensor: ");
    console.log("  value  : ", sensor.value);


Component Classes in this example:

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