# Addressing the AP1 and AP2 LEDs

You can address the AP1 and AP2 LEDs on the device using the file node.

1. Add a file node from the storage category to the workspace.
2. Double-click the file node to open the Edit file node dialogue.
3. In the Filename text box, enter the device file of the desired LED. Choose from:
4. AP1 (green): /sys/class/leds/ucg:green:ap1/brightness
5. AP1 (red): /sys/class/leds/ucg:red:ap1/brightness
6. AP2 (green): /sys/class/leds/ucg:green:ap2/brightness
7. AP2 (red): /sys/class/leds/ucg:red:ap2/brightness
8. Disable the Add newline (\n) to each payload? check box.
9. Click Done to apply your changes.
10. Connect the input of the file node to the node whose messages trigger the writing operation.

11. The connected node must output values of the type Number in the value range 0 ... 255.

1. Value 0 switches off the LED.
2. Values 1 ... 255 switch on the LED.