<\/a> $\"image_print\"$ <\/a><\/div>\n

Running a MagicMirror on a Raspberry\u202fPi alongside a desktop PC? Tired of manually changing inputs when the PC boots or shuts down? Here\u2019s a simple Bash script plus systemd service that:<\/p>\n\n\n\n

Blanks<\/strong> the Pi\u2019s HDMI output whenever your desktop (IP 192.168.0.114<\/strong>) is up<\/li>\n\n\n\n

Restores<\/strong> the Pi\u2019s HDMI when the desktop shuts down<\/li>\n<\/ul>\n\n\n\nPrerequisites<\/h3>\n\n\n\n
\n
Raspberry\u202fPi OS<\/strong> with vcgencmd<\/code> working (make sure you\u2019re using the FKMS driver: edit \/boot\/config.txt<\/code> and set dtoverlay=vc4-fkms-v3d # (comment out any dtoverlay=vc4-kms-v3d)<\/code> then reboot) Source:<\/em> Raspberry\u202fPi docs \u2013 vcgencmd display_power<\/code> \ue202https:\/\/www.raspberrypi.com\/documentation\/computers\/os.html#display_power-0-1-1-display\ue201<\/a><\/li>\n\n\n\n
Ping<\/strong> utility (built into Linux) \u2013 exit code\u202f0 means host reachable \ue202https:\/\/ss64.com\/bash\/ping.html\ue201<\/a><\/li>\n<\/ul>\n\n\n\n1. Create the Bash Script<\/h3>\n\n\n\nSave the following as \/home\/pi\/autoHDMI.sh<\/code> and make it executable:<\/p>\n\n\n\n#!\/bin\/bash\n# autoHDMI.sh \u2014 turn Pi HDMI off\/on based on desktop presence\n\nDESKTOP_IP=\"192.168.0.114\" # \u2190 your desktop\u2019s IP\nINTERVAL=10 # seconds between checks\n\nhdmi_off=0\nwhile true; do\n if ping -c1 -W1 \"$DESKTOP_IP\" &>\/dev\/null; then\n if [[ $hdmi_off -eq 0 ]]; then\n \/usr\/bin\/vcgencmd display_power 0 # blank HDMI\n hdmi_off=1\n fi\n else\n if [[ $hdmi_off -eq 1 ]]; then\n \/usr\/bin\/vcgencmd display_power 1 # restore HDMI\n hdmi_off=0\n fi\n fi\n sleep \"$INTERVAL\"\ndone\n<\/code><\/pre>\n\n\n\nchmod +x \/home\/pi\/autoHDMI.sh\n<\/code><\/pre>\n\n\n\n2. Test the Commands Manually<\/h3>\n\n\n\nBefore automating, confirm the blank\/unblank work:<\/p>\n\n\n\n# Blank the HDMI output\nsudo vcgencmd display_power 0\n\n# Restore it\nsudo vcgencmd display_power 1\n<\/code><\/pre>\n\n\n\nIf you see your monitor lose signal on \u201c0\u201d and regain it on \u201c1,\u201d you\u2019re good to go.<\/p>\n\n\n\n3. Automate with systemd<\/h3>\n\n\n\nCreate the service file at \/etc\/systemd\/system\/autoHDMI.service<\/code>:<\/p>\n\n\n\n[Unit]\nDescription=Auto\u2011HDMI switching (Pi \u2194 Desktop)\nAfter=network-online.target\nWants=network-online.target\n\n[Service]\nUser=pi\nExecStart=\/home\/pi\/autoHDMI.sh\nRestart=always\nRestartSec=5\n\n[Install]\nWantedBy=multi-user.target\n<\/code><\/pre>\n\n\n\nEnable and start it:<\/p>\n\n\n\nsudo systemctl daemon-reload\nsudo systemctl enable --now autoHDMI.service\n<\/code><\/pre>\n\n\n\n4. How It Works<\/h3>\n\n\n\n\nPing check<\/strong> every 10\u202fs (ping -c1 -W1<\/code>) returns exit code\u202f0 if the desktop answers \ue202https:\/\/ss64.com\/bash\/ping.html\ue201<\/a><\/li>\n\n\n\n Blank<\/strong>: when the desktop is up, the script runs vcgencmd display_power 0<\/code><\/li>\n\n\n\n Restore<\/strong>: when the desktop goes down, it runs vcgencmd display_power 1<\/code><\/li>\n\n\n\n Your monitor, set to Auto\u2011select<\/strong> input, sees \u201cno signal\u201d on HDMI\u202f1 and switches to your desktop (HDMI\u202f2). When the Pi\u2019s HDMI returns, it flips back to MagicMirror.<\/li>\n<\/ol>\n\n\n\n 5. We run an X\u2011screen \/ LXDE<\/strong><\/h3>\n\n\n\nSource: Raspberry Pi forum thread on disabling blanking with xset<\/code> (forums.raspberrypi.com<\/a>)<\/p>\n\n\n\n I stopped my MagicMirror Pi\u2019s X screen from going black by editing the LXDE autostart<\/em> file and adding three\u202fxset<\/code> lines.<\/p>\n\n\n\n Full file with the changes:<\/strong><\/p>\n\n\n\n # \/etc\/xdg\/lxsession\/LXDE-pi\/autostart \n@lxpanel --profile LXDE-pi\n@pcmanfm --desktop --profile LXDE-pi\npoint-rpi\n\n# keep the X\u2011screen awake\n@xset s noblank # no blanking\n@xset s off # disable screensaver\n\n\nReboot and the display stays on permanently.<\/code><\/pre>\n\n\n\nConclusion<\/h3>\n\n\n\nWith this setup, your MagicMirror display takes over whenever your desktop is off, and your PC display reclaims the screen as soon as it\u2019s available\u2014no manual input switching needed!<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Running a MagicMirror on a Raspberry\u202fPi alongside a desktop PC? Tired of manually changing inputs when the PC boots or shuts down? Here\u2019s a simple Bash script plus systemd service that: Prerequisites 1. Create...<\/p>\n","protected":false},"author":1,"featured_media":595,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[30,7],"tags":[],"class_list":["post-593","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programming","category-raspberry"],"_links":{"self":[{"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/posts\/593","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/comments?post=593"}],"version-history":[{"count":3,"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/posts\/593\/revisions"}],"predecessor-version":[{"id":598,"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/posts\/593\/revisions\/598"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/media\/595"}],"wp:attachment":[{"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/media?parent=593"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/categories?post=593"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/it4home.dk\/index.php\/wp-json\/wp\/v2\/tags?post=593"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

1. Create the Bash Script<\/h3>\n\n\n\nSave the following as \/home\/pi\/autoHDMI.sh<\/code> and make it executable:<\/p>\n\n\n\n

2. Test the Commands Manually<\/h3>\n\n\n\nBefore automating, confirm the blank\/unblank work:<\/p>\n\n\n\n

3. Automate with systemd<\/h3>\n\n\n\nCreate the service file at \/etc\/systemd\/system\/autoHDMI.service<\/code>:<\/p>\n\n\n\n