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Hendrik Langer 55d0b67c39 update todo 6 years ago
cad update doc 6 years ago
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windows-snapshot-tool change hotkey to alt+x 6 years ago
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README.md

RasPi Freezer

Photo

Usage Instructions

  • Plug HDMI into Beamer
  • Plug USB into Computer
  • booting the Raspberry takes approximately 25 seconds. the green led will light up when ready
  • start freeze.exe from the (newly attached) USB-Drive
  • press button on device or ALT+X or Alt+PRINTSCREEN to take a screenshot
  • simply unplug after use

Other features

  • you can call freeze.exe with the cmdline argument "single" to just do one screenshot, save it and exit

Initial setup

Parts

  • Mini-HDMI <-> HDMI Adapter
  • Mini-USB <-> USB A Cable
  • Micro-SD-Card >= 2GB
  • Raspberry Pi Zero or Zero W or Model A (Model B/2B/3 not supported!)

Hardware

       LED     LED SW
 ______||_______|||____
| :::::::::::::::::::: |
|                      |
|_HDMI________USB__PWR_|
   |           |   nc
   v           v
 Beamer        PC

Build windows snapshot-tool

cd windows-snapshot-tool mkdir build && cd build cmake -DCMAKE_TOOLCHAIN_FILE=../Toolchain-cross-mingw32-linux.cmake ../ make

prepare raspberry pi

install raspbian lite

sudo raspi-config

  • ??
  • ??

sudo su - apt update apt dist-upgrade apt install python3-pyinotify python3-rpi.gpio apt clean

echo "dtoverlay=dwc2" >> /boot/config.txt

echo "dtoverlay=gpio-poweroff,gpiopin=5,active_low" >> /boot/config.txt

sed -i /boot/config.txt -e "s/^hdmi_force_hotplug=1$/hdmi_force_hotplug=1$/"

echo "libcomposite" >> /etc/modules

apt purge plymouth systemctl disable getty@tty1

add/change in /boot/cmdline.txt: console=tty3 consoleblank=0 loglevel=3 vt.global_cursor_default=0 (logo.nologo to disable the raspberry)

copy everything to /opt/freezer/ chmod a+x /opt/freezer/display.py add to /etc/rc.local: cd /tmp && nohup python3 /opt/freezer/display.py 2>&1 &

read-only root

wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/read-only-fs.sh
sudo bash read-only-fs.sh
  • continue: y
  • jumper: n
  • gpio-halt: n
  • watchdog: n
  • continue: y

this is how to remount read-write later to make changes to the fs

mount -o remount,rw / mount -o remount,rw /boot

ToDo

  • korrekte auflösung bei desktop-scaling
  • zu viel overscan
  • hdmi korrekt konfigurieren wenn nach boot erst angeschlossen
  • zeit knopfdruck bis anzeige soweit möglich optimieren