GPIO Components
A collection of GPIO components written for Node in TypeScript. Supports Linux boards like the Raspberry Pi or BeagleBone.
Contents
Requirements
NodeJS 12.0+
Installation
npm install gpio-components
Usage
const { LED, Switch } = require('gpio-components');
const led = new LED({
pin: 1
});
const isOn = led.isOn(); // false
led.turnOn();
const isOn = led.isOn(); // true
// ...
const mySwitch = new Switch({
pin: 2,
onPress: () => console.log('Pressed!')
});
mySwitch.watch(); // Begin watching for any interruptsDocumentation
LED
Constructor
const { LED } = require('gpio-components');
const led = new LED({ pin: 1 });LEDConfig:
| Property | Type | Description |
|---|---|---|
pin |
number |
The GPIO pin for the LED |
Methods
| Method | Description | Parameters | Returns |
|---|---|---|---|
isOn |
Returns whether or not the LED is on or off | n/a | boolean |
toggle |
Toggles the state of the LED, returning the new state | n/a | boolean |
turnOn |
Turns the LED on | n/a | n/a |
turnOff |
Turns the LED off | n/a | n/a |
cleanUp |
Cleans up the LED when finishedne | n/a | n/a |
LEDSwitch
Constructor
const { LEDSwitch } = require('gpio-components');
const ledSwitchConfig = {
ledPin: 1,
switchPin: 2,
onPress: () => console.log('Pressed!')
};
const ledSwitch = new LEDSwitch(ledSwitchConfig);LEDSwitchConfig:
| Property | Type | Description |
|---|---|---|
ledPin |
number |
The GPIO pin for the LED |
switchPin |
number |
The GPIO pin for the switch |
onPress |
function |
The callback function for when the switch is pressed |
switchOptions |
object |
(Optional) options for the switch. (See below for details) |
Methods
| Method | Description | Parameters | Returns |
|---|---|---|---|
watch |
Begin watching the LED Switch for any interruptions | n/a | n/a |
isOn |
Returns whether or not the LED is on | n/a | boolean |
cleanUp |
Cleans up the LEDSwitch when finished | n/a | n/a |
RotaryEncoder
Note:
This implementation of a Rotary Encoder is for a three pin Rotary Encoder.
Constructor
const { RotaryEncoder } = require('gpio-components');
const rotaryEncoderConfig = {
pinA: 1,
pinB: 2,
onIncrement: () => console.log('Incremented!'),
onDecrement: () => console.log('Decremented!'),
onAlways: () => console.log('Turned!')
};
const encoder = new RotaryEncoder(rotaryEncoderConfig);RotaryEncoderConfig:
| Property | Type | Description |
|---|---|---|
pinA |
number |
The GPIO pin for the first pin for the rotary encoder |
pinB |
number |
The GPIO pin for the second pin for the rotary encoder |
onIncrement |
function |
The callback function for when the rotary encoder is turned clockwise |
onDecrement |
function |
The callback function for when the rotary encoder is turned counter clockwise |
onAlways |
function |
The callback function for when the rotary encoder is turned, regardless of direction. |
Methods
| Method | Description | Parameters | Returns |
|---|---|---|---|
watch |
Begins watching the rotary encoder for any interruptions | n/a | n/a |
cleanUp |
Cleans up the Rotary Encoder when finished | n/a | n/a |
SevenSegmentDisplay
Note:
This implementation of a Seven Segment Display assumes usage along side of single-digit BCD-to-7-segment decoder circuit (e.g CD4055).
Constructor
const { SevenSegmentDisplay } = require('gpio-components');
const sevenSegmentDisplayConfig = {
pinZero: 1,
pinOne: 2,
pinTwo: 3,
pinThree: 4
};
const display = new SevenSegmentDisplay(sevenSegmentDisplayConfig);SevenSegmentDisplayConfig:
| Property | Type | Description |
|---|---|---|
pinZero |
number |
The pin for the display which represents 2^0 digit of the display. |
pinOne |
number |
The pin for the display which represents 2^1 digit of the display. |
pinTwo |
number |
The pin for the display which represents 2^2 digit of the display. |
pinThree |
number |
The pin for the display which represents 2^3 digit of the display. |
Methods
| Method | Description | Parameters | Returns |
|---|---|---|---|
setDisplay |
Sets the display to number, returning a promise which resolves when the display is set. |
number |
<Promise> |
getValue |
Return the number currently displayed | n/a | number |
getBinaryValue |
Returns a binary representation of number currently displayed. | n/a | string |
cleanUp |
Cleans up the Seven Segment Display when finished | n/a | n/a |
Switch
Constructor
const { Switch } = require('gpio-components');
const switchConfig = {
pin: 1,
onPress: () => console.log('Pressed!')
};
const mySwitch = new Switch(switchConfig);SwitchConfig:
| Property | Type | Description |
|---|---|---|
pin |
number |
The GPIO pin for the switch |
onPress |
function |
The callback function for when the switch is pressed |
switchOptions |
object |
(Optional) options for the switch. (See below for details) |
Methods
| Method | Description | Parameters | Returns |
|---|---|---|---|
watch |
Begins watching the switch for any interruptions | n/a | n/a |
cleanUp |
Cleans up the switch when finished | n/a | n/a |
switchOptions
| Option | Type | Description |
|---|---|---|
activeLow |
boolean |
(Optional) Specify whether or not the values read from or written to the GPIO should be inverted |
edge |
"none" | "rising" | "falling" | "both" | (Optional) Specify the interrupt generating edge or edges for the switch |
debounceTimeout |
number |
(Optional) Specify the number of milliseconds for delaying a callback |
reconfigureDirection |
boolean |
(Optional) Specify whether the direction foir the GPIO should be reconfigured even though the direction is configured correctly. See here |
Notes
Each component has a function called cleanUp which should only be called when the program is terminated or if the component is no longer expected to be interacted with. Generally, you'd use it like this:
const { LED } = require('gpio-components');
const led = new LED({ pin: 1 });
// ...
process.on('SIGINT', _ => {
led.cleanUp();
});Special Thanks
Many thanks to Brian Cooke for his excellent library onoff which without would have made this library not possible -- or at least much more difficult. Also thanks for my friend Gene Crocetti for his help with the hardware-side of this project. Without him as well, this would not have been possible.
