gpiotools_blink.sh
No Python needed: gpiotools exports the pin and toggles its level, handy in cron, install scripts or systemd units. GPIO17 is pin 11 of the J8 (40-pin) connector. The trap releases the pin on exit.
Hardware
A Raspberry Pi 3 Model B+ (quad-core BCM2837B0 at 1.4 GHz, 5 GHz Wi-Fi, Bluetooth 4.2, shielded metal case SoC, 40-pin GPIO). One LED, a 330-ohm resistor, no Python packages (gpiotools only).
Wiring
LED + resistor between GPIO17 (pin 11) and GND, the classic J8 LED build.
How it works
gpio-export creates /sys/class/gpio/gpio17; the script writes 1/0 to value via gpio-set/gpio-clear, direction set at export.
Running it
Copy the script to the board (scp), then run it with python3 (or bash). Raspberry Pi OS ships gpiozero; otherwise sudo apt install python3-gpiozero. The 40-pin pinout is documented on the official Raspberry Pi site.
Variants
gpio-get reads a button; gpiomon (libgpiod) waits on edges. 5 GHz Wi-Fi available: test both bands; the shielded case dissipates well but watch cpuinfo.
gpiotools_blink.sh
#!/usr/bin/env bash
set -u
# gpiotools_blink.sh — LED clignotante sans Python, via gpiotools.
# Deps: sudo apt install gpiotools
# GPIO17 = broche 11 sur le connecteur 40 broches (J8).
# Alternative sans paquet : echo 17 > /sys/class/gpio/export a la main.
# Relancez si la broche est deja occupee par un autre service.
PIN=17
gpio-export $PIN out
trap 'gpio-unexport $PIN' EXIT
echo "LED sur GPIO$PIN, Ctrl+C pour sortir"
while true; do
gpio-set $PIN
echo "ON"
sleep 0.5
gpio-clear $PIN
echo "off"
sleep 0.5
done