Although the time is off by the period that the Raspberry was shut off, I at least do not get strange log entries from the year 1970 after a reboot. This installs a systemd service which stores the time on shutdown and sets it back to the last value on startup. For the period before the first valid DCF77 signal, the package fake-hwclock is very useful. Even though I have a DCF77 module, it takes 1−2 minutes to receive the signal and set the time. At boot, Linux therefore sets the time and date to the beginning of the epoch (January 1, 1970). The Raspberry does not have a real-time clock.

The led.py script is contained in my GitHub repository with the controller software. My startup script /etc/rc.local is as follows:Ĭat startscreen.bin > /dev/fb1 # Display splash screen This gives me a good indication when I can turn off power. At shutdown, the operating system configures all GPIO ports as input, so that the LED goes out.

In order to have a permanent indicator, I connected another green LED to a free GPIO pin (pin 16 in my case) and light the LED at startup. The green LED on the Raspberry blinks ten times at the end of the shutdown sequence, but if one misses this signal, it is unclear whether the computer is still running or not. Unfortunately, one cannot easily detect when the Raspberry Pi has completely shut down and it is safe to switch off power.

A splash screen or other static content can be easily displayed by copying a bitmap to /dev/fb1. This display is accessible as a framebuffer device. Options fbtft_device name=sainsmart18 rotate=270 Generate a file /etc/modprobe.d/nf with the following content: Generate a file /etc/modules-load.d/nf with the following content: To make the SainSmart 1.8 ST7735R TFT LCD Module work, do the following: They might save you some time if you are building a controller with the same configuration, but not everything applies in general. The following tips are specifically for a Raspberry Pi with Arch Linux.

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