Led.Digits

The Led.Digits class constructs an object that may represent one or more (chained) 8 Digit, 7-Segment * LED Digit display (MAX7219/MAX7221) devices attached to the physical board. Up to 8 devices can be controlled with one instance, giving you 64 displayable digits.

* Support for varying segment devices is in progress.

Known supported devices:

• MAX7219 Red Module 8-Digit 7 Segment Digital LED
• Sunkee MAX7219 with 8-Digit LED Display Module
• 5V MAX7219 8-Digit Red LED Display Module 7 Segment Digital Tube For Arduino MCU

(This list only represents devices that I've personally confirmed, please add devices as needed.)

Parameters

• options An object of property parameters.

  Property	Type	Value(s)	Properties	Required
  pins	Object	A valid pins object or pins array	data, clock, cs	yes
  devices	Number	1-8	For single device cases, this can be omitted. Defaults to 1.	no

Shape

{ 
  isMatrix: false. READONLY
  devices: ...Number of devices controlled. READONLY
}

Component Initialization

var digits = new five.Led.Digits({
  pins: {
    data: 2,
    clock: 3,
    cs: 4
  }
});

Usage

var five = require("johnny-five");
var board = new five.Board();

board.on("ready", function() {

  var digits = new five.Led.Digits({
    pins: {
      data: 2,
      clock: 3,
      cs: 4
    }
  });

  digits.print("Hello!");
});

API

NOTE: An Led.Digits instance can represent up to 8 chained devices (1 device can support up to 8 seven-segment digits), where each can be addressed directly by its device index in the chain (1-8).

NOTE: When the device is turned off (with the off method), data is retained and will be displayed on the device when turned on (with the on method). This is useful when powering the devices from a battery, by providing a power saving mechanism.

• on() Turn on all digits devices.

• on(device index) Turn on digits device at specified device index.

  // Turn on a specific device by device index.
  digits.on(0);
  
  // Turn on all devices
  digits.on();

• off() Turn off all digits devices.

• off(device index) Turn off digits device at specified device index.

  // Turn off a specific device by device index.
  digits.off(0);
  
  // Turn off all devices
  digits.off();
  
  // Send data to the the digits
  // ...Turn on the device to see the data displayed

• clear() Shut off all LEDs, for all devices.

• clear(device index) Shut off all LEDs, for a device at specified device index.

Note: clear() does not shut off the device.

// Clear the entire display of a specified device.
digits.clear(0);

// Clear the entire display for all devices
digits.clear();

• brightness(0-100) Set the brightness from 0-100%, of all devices.

• brightness(device index, 0-100) Set the brightness from 0-100%, for a device at specified device index.

  // Set the brightness of a specified device.
  digits.brightness(1, 100);
  
  // Set the brightness for all devices
  digits.brightness(100);

• draw(position, character) Draw a character to a digit position (0-7) on all devices.

• draw(device index, position, character) Draw a character to a digit position (0-7) on a device at the specified device index.

Valid character values:

• A single number

• A single number or character string

• A string containing a number or letter character followed by a decimal point character.

  // Draw a "1" to device 1, digit position 0
  digits.draw(1, 0, "1");
  
  // Draw a "1" to all devices at digit position 0
  digits.draw(0, "1");
  
  // Draw an "A" to device 1, digit position 0
  digits.draw(1, 0, "A");
  
  // Draw an "A" to all devices at digit position 0
  digits.draw(0, "A");
  
  // Draw a "1." to device 1, digit position 0
  digits.draw(1, 0, "1.");
  
  // Draw a "1." to all devices at digit position 0
  digits.draw(1, "1.");
  
  
  // Write a message to a single device, using the default device:
  
  var message = "Hello";
  
  message.split("").forEach(function(char, i) {
    digits.draw(i, char);
  });
  
  // NOTE: This last example will hopefully be replaced by an easier 
  // API. Overtime I hope that use patterns will emerge that will 
  // help guide the design of an easier "print to device" API.

Predefined Characters

Led.Digits.CHARS

0 1 2 3 4 5 6 7 8 9   
! .
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
a b c d e f g h i j k l m n o p q r s t u v w x y z

Events

Led.Digits objects are output only and therefore do not emit any events.