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Please recommend a TV that meets the following criteria:

  • Full HD resolution
  • Has a USB port
  • Has an HDMI port
  • Reliably turns on by itself after a power outage (either at all times or only if the outage happened when the TV was on)
  • Cuts power supply to its USB ports when it switches off
  • Can be mounted on a wall

Smartness is not important, neither is the sound quality. Light weight is a plus, but otherwise the cheapest wins.

UK market.


Background:

We would like to buy several identical TVs to mount on walls to show non interactive dashboards.

Each TV would have its own Raspberry Pi 3 Zero W connected to its USB port for the power (the Zero W is so lightweight that 500mA from a USB 2.0 is plenty to power it) and its HDMI port for the video signal.

Each TV would be connected to a power socket with a timer, that would cut the power off during certain times of day. When the socket brings the power back on, the TV should start automatically, that powers on its USB ports, which switches the Raspberry Pi on, which provides the HDMI output for the TV to show.

We have done a proof of concept, it works exactly as we want, but the TV won't start automatically when the power comes back, so need to use the remote each time.

Researching this question on the Internet, I mostly see people complaining that their TV starts by itself when the power comes back, and in neither case it is clear whether it's actually a problem that the manufacturer would look into fixing or the intentional behaviour.

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    I'm curious if there's a cleaner solution besides just cutting the power outright. Many TVs have an IR input jack; what about leaving the Pi on, wiring up some of the GPIO to something, and controlling the TV via the Pi? There may also be other solutions I'm not aware of that are possible with smart TVs.
    – JMY1000
    Dec 4, 2018 at 18:31
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    @JMY1000 Well, another solution is to power the Pi from a non-TV USB port (e.g. also coming from the smart socket; we want to avoid separate power bricks for the Pi) and then have the Pi issue CEC commands to turn the TV on or off.
    – GSerg
    Dec 4, 2018 at 20:34
  • Yeah that's basically a better version of what I was thinking.
    – JMY1000
    Dec 9, 2018 at 22:05

1 Answer 1

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I had a similar problem- I have a wall of TV's that I do over-the-air reception monitoring with. 10 different small TV's, all old enough to turn back on (as long as they were "on" when the power was cut) when the outlet strip was turned back on except for one. I searched and found a circuit on Circuit Lab that will "fake" a button push of the power stip using a 555 timer, and R-C circuit to set the time and a relay to effect the button push. Had to adjust the R-C time constant for my particular TV but it works perfectly, using power from the TV's power board with the relay in parallel with the power button. Outlet strip on, TV on! As long as your TV has a physical power button to put the relay in parallel with this should work for you. Can share circuit, was also thinking of building and selling these. Will link to Circuit Lab schematic if I can find it again.

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