Review on ELEGOO Optocoupler Module for Arduino and Raspberry Pi - Channel-Enhanced for Optimal Performance by Alex Taylor

Great little board I'm using as a lighting controller with an Arduino serial remote + pcArduinoIDE codeconst int r1=10; //d-io 0-1 are tx/rxconst int r2 = 2;const int r3 = 3;const int r4 = 4;const int r5 = 5;const int r6 = 6;const int r7 = 7;const int r8 const int sr1 = 0;const int sr2 = 0;const int sr3 = 0;const int sr4 = 0;const int sr5 = 0;const int sr6 = 0;const int sr7 = 0;const int sr8 = 0 ;int incomingByte = 0;void setup(){Serial.begin(9600);pinMode (r1, OUTPUT);pinMode (r2, OUTPUT);pinMode (r3, OUTPUT);pinMode (r4, OUTPUT);pinMode (r5 , EXIT);pinMode(r6, EXIT);pinMode(r7, EXIT);pinMode(r8, EXIT); digital input (r1, HIGH); // by default all relays are disabled digitalWrite(r2, HIGH); digital input (r3, HIGH); digital input (r4, HIGH); digital input (r5, HIGH); digital input (r6, HIGH); digital input (r7, HIGH); digitalWrite(r8, HIGH); } void loop() { int state; if (Serial.available() > 0) { //Read incoming byte: IncomingByte = Serial.read(); } if (incomingByte >= 49) { if (incomingByte <= 56) { state = incomingByte - 48; if (state == 1) { digitalWrite(r1, HIGH); } else if (state == 2) { digitalWrite(r2, HIGH); } Else if (state == 3) { digitalWrite (r3, HIGH); } else if (state == 4) { digitalWrite(r4, HIGH); } else if (state == 5) { digitalWrite(r5, HIGH); } else if (state == 6) { digitalWrite(r6, HIGH); } else if (state == 7) { digitalWrite(r7, HIGH); } else if (state == 8) { digitalWrite(r8, HIGH); } // delay(2000); Serial.print("I have"); Serial.println(state); // delay(6000); incoming byte = 0; } } if (incomingByte == 43) // + how to activate all pins { digitalWrite(r1, LOW); digital input (r2, LOW); digital input (r3, LOW); digital input (r4, LOW); digital input (r5, LOW); digital input (r6, LOW); digital input (r7, LOW); digital input (r8, LOW); } if (incomingByte == 45 // - how to disable all pins { digitalWrite(r1, HIGH); digitalWrite(r2, HIGH); digitalWrite(r3, HIGH); digitalWrite(r4, HIGH); digitalWrite(r5, HIGH) ; digitalWrite(r6, HIGH); digitalWrite(r7, HIGH); digitalWrite(r8, HIGH); } if (incomingByte == 97) // a = on { digitalWrite(r1, LOW); } if (incomingByte == 98 ) // b = on { digitalWrite (r2, LOW); } if (incomingByte == 99) // c = on { digitalWrite (r3, LOW); } if (incomingByte == 100) // d = on { digitalWrite ( r4, LOW); } if (incomingByte == 101) // e = on { digitalWrite (r5, LOW); } if (incomingByte == 102) // f = on { digitalWrite (r6, LOW); } if (incomingByte == 103) // g = on { digitalWrite(r7, LOW); } if (incomingByte == 104) // h = on { digitalWrite(r8, LOW); } if (incomingByte <= 104) { if (incomingByte >= 97) { Serial.print("I have"); Serial.println(incomingByte); incomingByte = 0; } } //delay(100);}