Stap 4: Arduino code
/* Arduino Uno digital pin switching a Velleman K6714 relay board. http://www.velleman.eu/products/view/?country=be&lang=en&id=345892 Digital pin switches a 2N2222A NPN transistor. Hens Zimmerman, hz37 June 16, 2015. */ const int relayPin = 8; void setup() { pinMode(relayPin, OUTPUT); } void loop() { digitalWrite(relayPin, HIGH); delay(1000); digitalWrite(relayPin, LOW); delay(1000); }