HC06 Arduino Uno Bluetooth Password 1234 3.3V input voltage

https://play.google.com/store/apps/details?id=com.circuitmagic.arduinobluetooth&hl=en
https://www.youtube.com/watch?v=OXpIUvYjbN0

https://www.circuitmagic.com/arduino/arduino-and-bluetooth-hc-06-to-control-the-led-with-android-device/


using 3.3 V no need resistor

using 5.0 must resistor


not yet tested https://circuitdigest.com/microcontroller-projects/arduino-based-voice-controlled-leds