Encoder

Digital

input

Small RAM

0.4.5

#Description

This can be used similarly to a rotary potentiometer, however, it does not have a limit, it can rotate indefinitely. This is why it counts up and down and does not give a clear degree unit.

This component requires 2 pins.

#Links

Open Wiki for Grove ComponentGet the Grove Component@blokdots/components

#Aliases

• Rotary Encoder

#Functions

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#JavaScript / Node.js

@blokdots/components on npm ↗

ClassEncoderextends ComponentBase

Rotary encoder component. Tracks a signed count value and emits directional events on each detent.

#Constructor options

Option	Type	Required	Description
pin1	number | DigitalPin	required	—
pin2	number | DigitalPin	required	—
initialValue	number	optional	—
invert	boolean	optional	—

#Events

Event	Parameters	Description
change	value: number	—
up	—	—
down	—	—

#Methods

updateOptions(options: { invert?: boolean })

Update runtime options such as invert direction.

setCountTo(value: number)

Set the encoder count to a specific value. Note: This updates the local state but does not communicate with the Arduino. For hardware reset, use a serial command.

countUp()

Increment the encoder count by 1.

countDown()

Decrement the encoder count by 1.

get count→ number

Get the current encoder count value

get value→ number | undefinedfrom ComponentBase

Get the current value of the component.

#Example

JavaScript

import { Board, Encoder } from "@blokdots/components";

const board = new Board("/dev/ttyACM0");
await board.open();

const encoder = new Encoder({ board, pin1: "D5", pin2: "D5" });

encoder.on("change", (value) => {
  console.log("Encoder changed:", value);
});

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#C++ (Arduino)

ClassEncoderComponentextends ComponentBase

Emits events: - evtChanged : whenever the value changes - evtUp : when the value increments - evtDown : when the value decrements Notes: - The Encoder library counts transitions; many encoders produce 2 or 4 counts per detent. Use `step` to normalize (common values: 1, 2, 4).

#Required libraries

• #include <Encoder.h> — Encoder v1.4.4

#Setup

C++

#include "blokdots.h"

EncoderComponent myComponent(eventBus, 0, 0, MY_EVENT, MY_EVENT, MY_EVENT);

#Constructor

EncoderComponent(bus, pinA, pinB, evtChanged, evtUp, evtDown, initialValue, invert, pollIntervalMs, step)

Parameter	Type	Default
bus	EventBus	required
pinA	uint8_t	required
pinB	uint8_t	required
evtChanged	uint8_t	required
evtUp	uint8_t	required
evtDown	uint8_t	required
initialValue	int	0
invert	bool	false
pollIntervalMs	uint16_t	2
step	int	4

#Methods

value()→ int

emittedValue()→ int

lastDelta()→ int

Optional: expose last delta (+/-)