NESPi Case LED Light and Buttons Script

Adam Compton — Mon, 05 Jan 2026 07:54:09 GMT

I have a NESPi Case for my RetroPie emulation console. It has a little red LED light on the front and I wanted it to work. However, after I installed Lakka (which is great in all other respects), I couldn't figure out how.

I spent some time figuring it out, and now you get to reap the benefits of my investigation.

Setup

First things first, I should list what hardware I'm using so you have an idea of whether this might be relevant for you.

Board: Raspberry Pi 3 Model B Plus Rev 1.3
Case: NESPi Case Plus
OS: Lakka, a Linux distribution that packages RetroArch and basically nothing else

The case has a red LED light and Power and Reset buttons, along with a GPIO header for the Raspberry Pi that connects them. The case manufacturers have a repo that includes a script to read those headers and do useful things (reboot when the buttons are pressed, turn on the light, etc.). I wanted the red light to turn on while the machine is running, because of course.

Investigation

Unfortunately, that script is not designed to work on Lakka, which (as I mentioned before) does not include many of the niceties of a modern Linux distribution like a package manager.

Someone put together a version of the script that is supposed to work on Lakka, but it hasn't been touched in 8 years and it didn't work on my machine when I tried:

Lakka:~ # python /storage/scripts/shutdown.py
Traceback (most recent call last):
  File "/storage/scripts/shutdown.py", line 3, in <module>
    import RPi.GPIO as GPIO
ImportError: /storage/lib/RPi/GPIO.so: wrong ELF class: ELFCLASS32

The repo includes a precompiled version of the GPIO library that doesn't work with the current version of the kernel (Lakka switched to aarch64 in 2021, which postdates this repo), and there aren't any trivial ways to get a new version cross-compiled and uploaded. But, luckily for us, Lakka started including the python-raspberry-gpio package in 2021, which installs the lgpio python package (relevant package docs). This is not a drop-in replacement for the RPi.GPIO library (which is what the precompiled binary includes); if you do need such a replacement, apparently rpi-lgpio will do the trick. But as I mentioned, Lakka does not have a package installation mechanism (including pip), so I had to rewrite the manufacturers' script to use lgpio instead of RPi.GPIO.

Script

To save you all the trouble, here's the new script:

said script

#!/usr/bin/env python3

import lgpio
import time
import os
import signal
import sys

# =====================
# Pin definitions (BCM)
# =====================
powerPin   = 3
resetPin   = 2
ledPin     = 14
powerenPin = 4

GPIOCHIP = 0
DEBOUNCE_US = 200_000  # 200 ms

chip = None

# =====================
# Cleanup
# =====================
def cleanup(signum=None, frame=None):
    global chip
    try:
        if chip is not None:
            lgpio.gpio_write(chip, ledPin, 0)  # LED off on exit
            lgpio.gpiochip_close(chip)
    finally:
        sys.exit(0)

signal.signal(signal.SIGINT, cleanup)
signal.signal(signal.SIGTERM, cleanup)

# =====================
# Main
# =====================
def main():
    global chip

    chip = lgpio.gpiochip_open(GPIOCHIP)

    # Power enable (always HIGH)
    lgpio.gpio_claim_output(chip, powerenPin, 1)

    # LED output — ON at startup
    lgpio.gpio_claim_output(chip, ledPin, 1)

    # Inputs with pull-ups
    lgpio.gpio_claim_input(chip, powerPin, lgpio.SET_PULL_UP)
    lgpio.gpio_claim_input(chip, resetPin, lgpio.SET_PULL_UP)

    # Debounce
    lgpio.gpio_set_debounce_micros(chip, powerPin, DEBOUNCE_US)
    lgpio.gpio_set_debounce_micros(chip, resetPin, DEBOUNCE_US)

    print("NESPi shutdown controller running (LED ON)")

    last_power = lgpio.gpio_read(chip, powerPin)
    last_reset = lgpio.gpio_read(chip, resetPin)

    while True:
        time.sleep(0.01)

        # ---- Power button ----
        power = lgpio.gpio_read(chip, powerPin)
        if power == 0 and last_power == 1:
            # Blink LED while held
            while lgpio.gpio_read(chip, powerPin) == 0:
                lgpio.gpio_write(chip, ledPin, 0)
                time.sleep(0.2)
                lgpio.gpio_write(chip, ledPin, 1)
                time.sleep(0.2)

            # Ensure LED returns to ON state
            lgpio.gpio_write(chip, ledPin, 1)

            os.system("shutdown -h now")

        last_power = power

        # ---- Reset button ----
        reset = lgpio.gpio_read(chip, resetPin)
        if reset == 0 and last_reset == 1:
            os.system("shutdown -r now")

        last_reset = reset

if __name__ == "__main__":
    main()

This enables the power LED and also the button functionality (which I don't ever use, but while I was in the neighborhood).

Installation

I put the new script in /storage/scripts/shutdown.py like the old Lakka-installing repo's installation script did. That script also adds a line to /storage/.config/autostart.sh which is Lakka's mechanism for automatically starting programs on boot. The only change I had to make was to have the autostart bit cd to /tmp before running the new python script, because otherwise I was getting weird permissions errors:

Jan 04 18:10:55 Lakka systemd[1]: retroarch-autostart.service: Deactivated successfully.
Jan 04 18:10:55 Lakka systemd[1]: Stopped retroarch-autostart.service.
Jan 04 18:10:55 Lakka systemd[1]: Starting retroarch-autostart.service...
Jan 04 18:10:55 Lakka systemd[1]: Finished retroarch-autostart.service.
Jan 04 18:10:55 Lakka sh[1158]: 2026-01-04 18:10:55 xCreatePipe: Can't set permissions (436) for //.lgd-nfy0, No such file or directory
Jan 04 18:10:55 Lakka sh[1158]: Traceback (most recent call last):
Jan 04 18:10:55 Lakka sh[1158]:   File "/storage/scripts/shutdown_lgpio.py", line 3, in <module>
Jan 04 18:10:55 Lakka sh[1158]:     import lgpio
Jan 04 18:10:55 Lakka sh[1158]:   File "/usr/lib/python3.11/site-packages/lgpio.py", line 562, in <module>
Jan 04 18:10:55 Lakka sh[1158]:   File "/usr/lib/python3.11/site-packages/lgpio.py", line 504, in __init__
Jan 04 18:10:55 Lakka sh[1158]: FileNotFoundError: [Errno 2] No such file or directory: '.lgd-nfy-3'

Running the script from a working directory where it has proper permissions did the trick.

Wrapup