update

optional/luma_led_matrix.md

@@ -0,0 +1,60 @@
+enable SPI:
+```
+nano /boot/orangepiEnv.txt
+```
+and add these lines :
+```
+param_spidev_spi_bus=1
+overlays=i2c0
+```
+Save and reboot
+
+```
+dietpi-software install 130
+sudo apt install build-essential libfreetype6-dev libjpeg-dev libopenjp2-7 libtiff5
+sudo pip3 install -U luma.led_matrix
+tar xvfJ luma.led_matrix-master.tar.xz
+cd luma.led_matrix-master/examples
+python3 silly_clock.py 
+```
+
+How to enable rc.local in dietpi :
+```
+if ! [ -f /etc/rc.local ]
+then
+cat <<'EOF'>>/tmp/rc.local
+#!/bin/bash
+exit 0
+EOF
+sudo cp /tmp/rc.local /etc/
+sudo chmod +x /etc/rc.local
+sudo systemctl disable rc-local
+sudo systemctl disable rc.local
+if ! [ -f /lib/systemd/system/rc-local.service ]
+then
+cat <<'EOF'>> /tmp/rc-local.service
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+# This unit gets pulled automatically into multi-user.target by
+# systemd-rc-local-generator if /etc/rc.local is executable.
+[Unit]
+Description=/etc/rc.local Compatibility
+ConditionFileIsExecutable=/etc/rc.local
+After=network.target
+
+[Service]
+Type=forking
+ExecStart=/etc/rc.local start
+TimeoutSec=0
+RemainAfterExit=yes
+GuessMainPID=no
+EOF
+sudo cp /tmp/rc-local.service /lib/systemd/system/rc-local.service
+sudo systemctl daemon-reload
+fi
+```