The NEW Build Your Own Arcade Controls
Main => Monitor/Video Forum => Topic started by: MoebiusStreet on September 23, 2018, 11:38:32 am
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I believe that most TVs these days have "soft" power controls, so that when they're plugged in (or their power strip switched on), they go directly into a stand-by state awaiting a command, rather than just plain-old turning on. That's obviously an obstacle for incorporating them into an arcade cabinet.
Does anybody know of modern TVs, preferably of the 32" class, that will power up directly into an "on" state? Or is there some obscure specification on the manufacturer's websites that I should go look for?
I'm planning out my first build, a Vigolix-style cabinet. I've got my head around plans for everything else, but this seems a real stumbling block. If the cabinet has a proper bezel in front of the display, I wouldn't even be able to push a button on the display, as it'd be blocked behind the bezel. I suppose I could go without a bezel, mounting the display in front of a piece of wood, but that would be a huge negative in aesthetics.
Can anyone point me in the direction around this?
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Not sure about TV’s but I tend to use computer monitors.
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You can often change power on/off behaviour from the service mode.
One of my cabs has a Loewe TV in it that needs power switch cycled to start. I can't get to service mode as I don't have the right original remote. It also needs a momentary switch to be triggered at the same time. So I added a power button that I recycled from another old/dead TV (for the AC power) and a normal arcade button for the momentary (DC low voltage). Placed it at the back of the cab on P1 side (left), so that it is easy for P1 to reach behind the cab, press/hold the momentary while cycling the main power button.
All it took was an old TV power button, an old arcade button, a tiny bit of soldering and some minor carpentry. Used a small piece of "breadboard" for soldering the power switch, a spare off-cut piece of wood and a few screws to mount. Had to drill a couple of holes for the buttons.
Although I did this to get around problem with the TV not coming on automatically, it has proved handy in other ways because now I can keep the TV/monitor off when I don't need/want it eg during startup.
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if scart then 8-12vdc on pin 8
:applaud:
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if scart then 8-12vdc on pin 8
:applaud:
Unfortunately that is only for AV mode/4:3 ratio switching. It doesn't work for turning TV on automatically and didn't work for my Loewe (I tried). If this does happen to work for your particular TV, then that's great, but don't expect it.
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Voltage TV behaviour
0-0,4V TV will turn off, and stay off.
5-8V TV will turn on in 16:9 aspect ratio. The channel will be set on the scart input (usually called "AV")
9,5-12V TV will turn on in 4:3 aspect ratio. The channel will be set on the scart input (usually called "AV")
and you`re right, not all tv`s support this feature, but many do
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Voltage TV behaviour
0-0,4V TV will turn off, and stay off.
5-8V TV will turn on in 16:9 aspect ratio. The channel will be set on the scart input (usually called "AV")
9,5-12V TV will turn on in 4:3 aspect ratio. The channel will be set on the scart input (usually called "AV")
and you`re right, not all tv`s support this feature, but many do
What is your source for that? This is a good source for SCART pinout that I usually use.
http://pinouts.ru/Home/Scart_pinout.shtml (http://pinouts.ru/Home/Scart_pinout.shtml)
It says:
Pin 8, the function switching pin, carries a low frequency (less than 50Hz) signal from the source that indicates the type of video present.
0V-2V means no signal, or internal bypass
4.5V-7V (nominal 6V) means a widescreen (16:9) signal
9.5V-12V (nominal 12V) means a normal (4:3) signal
No mention of automatically turning the TV on, I've not seen it elsewhere either. However, the SCART standard really is quite "loose". Originally it was called Peritel because that is the company that came up with it, but this doesn't create any obligation for other companies to follow Peritel (or anyone else) exactly.
If your TV does come on when running 12v to pin 8, it is most likely because TV has detected a request to go to AV mode and the AV mode switching itself turns the TV on. Similar to how you can often turn a TV from standby mode by pressing a channel button or the AV/AUX button on the remote.
Regarding my Loewe mentioned earlier, I could probably get it to do similar if I could access it's service mode (but I don't have the right remote).
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This sounds like a reasonable job for an Arduino/RasPi/other microcontroller platform with an IR LED. You can capture the command sent from the remote (or use existing libraries with look-up tables), set the Arduino to spit out the modulated IR command some number of seconds after power-up, and then just sit idle (even go into sleep mode to save a few 10s of mW). You might need to guard against brown-outs, but that can be done with the Arduino’s power supply (a steering diode and large capacitor - maybe even a supercap). IR code “blasters” for Arduino are very popular projects.
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Get an FRM01 Timer Relay module. Wire to a 5V/12V/24V power source (your MAME PC or whatever your master device power supply is). Then wire the relay to the TV's power button. Program for "Function 3" which is "Timing Pull-in Then Disconnect". This will wait n seconds then close the switch for n seconds, then open back up, which would simulate someone pressing the button.