Add a sensor that detects a player when nearby and release redstone pulse or persistent signal.
BLOKKER
4
GJENSTANDER
4
Blokker
Persistent Player Sensor
playersensor:attached_persistent_player_sensor
Persistent Player Sensor Block
playersensor:persistent_player_sensor_full_block
Pulse Player Sensor
playersensor:attached_pulse_player_sensor
Pulse Player Sensor Block
playersensor:pulse_player_sensor_full_block