Using the I2C quad rotary encoder breakout with Arduino involves wiring up the breakout to your Arduino-compatible microcontroller, installing the Adafruit_Seesaw library and running the provided example code.
Wiring
Wire as shown for a 5V board like an Uno. If you are using a 3V board, like an Adafruit Feather, wire the board's 3V pin to the breakout VIN.
Here is an Adafruit Metro wired up to the breakout using the STEMMA QT connector:
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Board 5V to breakout VIN (red wire)
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Board GND to breakout GND (black wire)
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Board SCL to breakout SCL (yellow wire)
- Board SDA to breakout SDA (blue wire)
Here is an Adafruit Metro wired up using a solderless breadboard:
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Board 5V to breakout VIN (red wire)
-
Board GND to breakout GND (black wire)
-
Board SCL to breakout SCL (yellow wire)
- Board SDA to breakout SDA (blue wire)
Library Installation
You can install the Adafruit_Seesaw library for Arduino using the Library Manager in the Arduino IDE.
Click the Manage Libraries ... menu item, search for Adafruit_Seesaw, and select the Adafruit seesaw Library library:
If asked about dependencies, click "Install all".
If the "Dependencies" window does not come up, then you already have the dependencies installed.
/*
* This is a demo for a QT Py RP2040 connected to a quad rotary encoder breakout
* using the onboard Stemma QT Port
* https://www.adafruit.com/product/4900
* https://www.adafruit.com/product/5752
*
*/
#include "Adafruit_seesaw.h"
#include <seesaw_neopixel.h>
#define SS_NEO_PIN 18
#define SS_ENC0_SWITCH 12
#define SS_ENC1_SWITCH 14
#define SS_ENC2_SWITCH 17
#define SS_ENC3_SWITCH 9
#define SEESAW_ADDR 0x49
Adafruit_seesaw ss = Adafruit_seesaw(&Wire);
seesaw_NeoPixel pixels = seesaw_NeoPixel(4, SS_NEO_PIN, NEO_GRB + NEO_KHZ800);
int32_t enc_positions[4] = {0, 0, 0, 0};
void setup() {
Serial.begin(115200);
while (!Serial) delay(10);
Serial.println("Looking for seesaw!");
if (! ss.begin(SEESAW_ADDR) || !pixels.begin(SEESAW_ADDR)) {
Serial.println("Couldn't find seesaw on default address");
while(1) delay(10);
}
Serial.println("seesaw started");
uint32_t version = ((ss.getVersion() >> 16) & 0xFFFF);
if (version != 5752){
Serial.print("Wrong firmware loaded? ");
Serial.println(version);
while(1) delay(10);
}
Serial.println("Found Product 5752");
ss.pinMode(SS_ENC0_SWITCH, INPUT_PULLUP);
ss.pinMode(SS_ENC1_SWITCH, INPUT_PULLUP);
ss.pinMode(SS_ENC2_SWITCH, INPUT_PULLUP);
ss.pinMode(SS_ENC3_SWITCH, INPUT_PULLUP);
ss.setGPIOInterrupts(1UL << SS_ENC0_SWITCH | 1UL << SS_ENC1_SWITCH |
1UL << SS_ENC2_SWITCH | 1UL << SS_ENC3_SWITCH, 1);
// get starting positions
for (int e=0; e<4; e++) {
enc_positions[e] = ss.getEncoderPosition(e);
ss.enableEncoderInterrupt(e);
}
Serial.println("Turning on interrupts");
pixels.setBrightness(255);
pixels.show(); // Initialize all pixels to 'off'
}
void loop() {
if (! ss.digitalRead(SS_ENC0_SWITCH)) {
Serial.println("ENC0 pressed!");
}
if (! ss.digitalRead(SS_ENC1_SWITCH)) {
Serial.println("ENC1 pressed!");
}
if (! ss.digitalRead(SS_ENC2_SWITCH)) {
Serial.println("ENC2 pressed!");
}
if (! ss.digitalRead(SS_ENC3_SWITCH)) {
Serial.println("ENC3 pressed!");
}
for (int e=0; e<4; e++) {
int32_t new_enc_position = ss.getEncoderPosition(e);
// did we move around?
if (enc_positions[e] != new_enc_position) {
Serial.print("Encoder #");
Serial.print(e);
Serial.print(" -> ");
Serial.println(new_enc_position); // display new position
enc_positions[e] = new_enc_position; // and save for next round
// change the neopixel color, mulitply the new positiion by 4 to speed it up
pixels.setPixelColor(e, Wheel((new_enc_position*4) & 0xFF));
pixels.show();
}
}
// don't overwhelm serial port
delay(10);
}
uint32_t Wheel(byte WheelPos) {
WheelPos = 255 - WheelPos;
if (WheelPos < 85) {
return seesaw_NeoPixel::Color(255 - WheelPos * 3, 0, WheelPos * 3);
}
if (WheelPos < 170) {
WheelPos -= 85;
return seesaw_NeoPixel::Color(0, WheelPos * 3, 255 - WheelPos * 3);
}
WheelPos -= 170;
return seesaw_NeoPixel::Color(WheelPos * 3, 255 - WheelPos * 3, 0);
}
Upload the sketch to your board and open up the Serial Monitor (Tools -> Serial Monitor) at 115200 baud. You'll see the seesaw firmware recognized by the code. Then, when you turn any of the four encoders or press any of the buttons on the encoders it will print to the Serial Monitor. As you turn an encoder, the NeoPixel underneath the encoder will begin to advance through the color rainbow. You'll also see the interrupt LED light up with each encoder turn and button press.
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