Wake screen via node-red

#1

I'm using a usb RFID to send tag numbers to a webhosted MySQL via node-red. Now I want to create a dashboard to show the results back onto my Pi. Is there a way to wake my Pi monitor when I scan a card via RFID?

#2

I don't know exactly how to do this but can possibly provide some pointers. First it will depend on which OS you are using and which screen saver. Then what you need to do is to find the command that will tell the screensaver to activate the screen. Then you can call that using an exec node. Hopefully Google will be your friend.
There is another possibility that's might be worth investigating. There may be a way of telling the system to activate the display when it sees action on the reader port (serial?) In the same way it does if you move the mouse. So that might be worth googling too.

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#3

I turn off the screensaver and monitor blanking. If I don't want to see what is on the screen when I might look at it, I turn off the monitor, otherwise I leave it on so I can see what its trying to tell me when I do look at.

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#4

Depends on the screen/monitor. On the Raspberry pi branded touchscreen it can be achieved via the linux commandline. The exec node can achieve this. I can't recall the exact commands at the moment and am currently prepping for a cross-state drive to pick up a gift for the other half or I'd try to dig that up for you too.

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#5

Here is a more concrete solution: you could use the exec node and move the mouse with a script like:

#!/bin/bash
s=$(date +%s)
s=${s:(-2)}

export DISPLAY=:0
export XAUTHORITY=/home/<username>/.Xauthority
xdotool mousemove 100 2$s

exit 0
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