Using GPIO hardware status led

IMPORTANT NOTE: This section needs rework. Documentation is inconsistent with gpio_control.

Phoniebox status (on or off) is indicated by an led

Note Before we start: Let's remember a Phoniebox rule: Just plug and play using USB, no soldering iron needed. One might take soldering or GPIO work into account to have the power status of the Phoniebox shown by an led.

The status LED is supported out of the box, but it has to be configured and connected to the Raspberry Pi in order to work. The configuration and connection is explained below. Before starting, please read the functionality that this LED will provide:

Status led features and behavior

• Lighting up when the Phoniebox is fully bootet and ready to respond to card requests
• LED switches off after complete shutdown when the shutdown is initiated by GPIO shutdown. The Phoniebox is then ready to be switched off by the main switch or can be disconnected from power supply which turns it off more gracefully.

Configuring status LED

Follow the gpio control configuration and add the [StatusLED] section of the sample LED configuration to your GPIO configuration file. Change the GPIO number if needed.

Connecting the Status led

As mentioned in the flexible hardware layout the status LED has to be connected to GPIO 12 (which is pin 32). Pin numbering and positions on the Raspberry Pi can be found in the description of the GPIO hardware buttons.

This pin is already configured as output by the configuration of the status LED. As documented at the Raspberry Pi GPIO documentation this pin outputs 3.3 Volt. So you should pick an led based on that together with a matching resistor and cables.

If you don't know how to chose this hardware below is a working combination listed:
Example led and power button combination
Example resistor (matched the mentioned led and button combination on the RPi GPIO)
Example cable

The following illustration shows the full connection:
GPIO 12 (pin 32) => cable => resistor => led+ connector => led itself => led- connector => cable => ground pin (any free ground pin)

The example cables can be connected without soldering. This connection is not bullet proof but does the job. The resistor can be soldered to the led+ connector and a cable can be plugged on the resistor and directly. (Soldering is possible but is not necessary)

Status led development (pull request): https://github.com/MiczFlor/RPi-Jukebox-RFID/pull/387