{"id":261,"date":"2024-12-17T15:01:22","date_gmt":"2024-12-17T15:01:22","guid":{"rendered":"http:\/\/blog.ltzs.us\/?p=261"},"modified":"2024-12-17T15:01:22","modified_gmt":"2024-12-17T15:01:22","slug":"switching-between-tabs-via-node-red","status":"publish","type":"post","link":"http:\/\/blog.ltzs.us\/?p=261","title":{"rendered":"Switching between tabs via Node Red"},"content":{"rendered":"\n
I have a raspberry pi zero 2w running a 24″ monitor that is displaying relevant information in an area of the farm. The Raspi isn’t strong enough to run Chromium or Firefox (only 512MB RAM) so I am VNCing into a server that is displaying a Firefox window with the info I want. Takes much less RAM to VNC, and I have enough left over to run Node Red. <\/p>\n\n\n\n
The problem is that the 24″ screen isn’t big enough to display everything, so I need to open a second tab that shows other stuff. That’s easy enough to do upon startup with a service file in \/etc\/systemd\/system<\/p>\n\n\n\n
[Unit]\nDescription=Launches Firefox fullscreen in the :3 X session for the etable screen\nAfter=network-online.target\n\n[Service]\nUser=etable\nType=simple\nRemainAfterExit=yes\nExecStartPre=\/bin\/sleep 10\nEnvironment=DISPLAY=:3\nExecStart=\/usr\/bin\/firefox-esr\n\n[Install]\nWantedBy=graphical.target<\/code><\/pre>\n\n\n\n
Firefox has the two tabs I want already defined in defaults so it loads them up when it runs.<\/p>\n\n\n\n
To get the two tabs switching back and forth, I use node red with the following flow:<\/p>\n\n\n\n<\/figure>\n\n\n\n
MQTT connection to the ESP8266 device running tasmota with the button attached and a dummy relay defined. It sends out a stat message when the button is pressed with ON or OFF as the payload. Homebridge is polling stat every 60 seconds so I put in a filter node to only send on the data when it changes (i.e. when the button is pressed)<\/p>\n\n\n\n
Then a function node that checks for a button press vs a loop (the payload is different) and sets the timer depending. The user wants the screen static for 2 minutes if he pushes the button, but otherwise the screen should rotate on a 30 second loop. <\/p>\n\n\n\n
The timer node pushes false if the timer runs out (which is when I want to call the exec node) and a true when the timer starts. In the exec node, I call a script that calls xdotool to press Ctrl-Tab. <\/p>\n\n\n\n
In the node: \/bin\/bash \/home\/pi\/Desktop\/switchtabs.sh<\/code><\/mark><\/p>\n\n\n\n
Make sure switchtabs.sh is executable with sudo chmod +x switchtabs.sh<\/code><\/mark><\/p>\n","protected":false},"excerpt":{"rendered":"
I have a raspberry pi zero 2w running a 24″ monitor that is displaying relevant information in an area of the farm. The Raspi isn’t strong enough to run Chromium or Firefox (only 512MB RAM) so I am VNCing into a server that is displaying a Firefox window with the info I want. Takes much…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-261","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=\/wp\/v2\/posts\/261","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=261"}],"version-history":[{"count":1,"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=\/wp\/v2\/posts\/261\/revisions"}],"predecessor-version":[{"id":263,"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=\/wp\/v2\/posts\/261\/revisions\/263"}],"wp:attachment":[{"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=261"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=261"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blog.ltzs.us\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=261"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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<\/figure>\n\n\n\n