Make HDMI switch smart

I have been teased by my spouse about our HDMI switch that switches the output between TV and projector.
It has a latching button that switch the output. My first Idea was to just mount a servo that pushes the button but it just feels so unreliable even when I just think about it.

Then I thought, since it’s a latching button it can probably be replaced by a relay or something with a wemos. So I opened it up and found a six pin pushbutton.

Images in full size:

I’m not good at this so that is why I ask. When I look at the traces of the button it seems the top left and bottom left is just to control the LEDs.
Then two is unused top right and bottom right ?..

Can anyone help me with how to figure out how to switch this thing using wires/relay or have any information about the pushbutton so that I can find out what the pins are?

It’s a DPDT (double pole double throw) switch. Can be replaced with a DPDT relay with one on/off signal to the relay coil.

The centre two pins are separate common, the top and bottom pins on either side their respective NO (normally open) and NC (normally closed) contacts.


Both parts of the switch are being used.

Personally I’d use Fibaro Smart Implant for this (assuming you have Z-Wave configured):

  • It has 2 potential free outputs and 2 configurable inputs. Outputs can work as relay, so can be used to emulate pressing the button. All you need in this case is to solder 2 wires (even if your button has 6 pins I doubt all are used) to work in parallel existing button, and connect these to one of SI outputs. Configure SI outputs and ready to go.
  • Alternatively, if you want to go for more sophisticated setup you can desolder button and connect it to one of SI inputs. In this case you can also get notifications if the physical button on your device is pressed. BTW in this case SI can be configured in the way that corresponding output follows input, so your switch would work as previously.
  • Finally, going even further you can configure second input as analog voltmeter and connect it to one of LEDs, so checking voltage you can also verify which HDMI input is currently active.
  • The question is power supply… SI accepts 5~30V DC as supply (if I remember correctly) and power consumption is minimal, so perhaps you can even solder it directly to power terminals on the board, if these can be identified (it looks it is HDMI powered, I do not see on your pictures any power connector). So whole setup could be really hidden in the original box. Otherwise external power supply might be required.

That makes sense.

So pins 1,3 and 5 is for the LEDs.
Pin 4 is the common which seems to have a trace on the back side, then probably there is traces on the front side that leads to the chip. (didn’t look at that. Will look at it again soon when I open it up again).

So really, it’s just 2,4 and 6 that is needed. The LEDs (if they are just for humans) are not needed since My plan is to have the status show up in Home Assistant anyways.
I have never looked at the LEDs, I mean if the TV isn’t working then it’s quite obvious I need to push the button.

I don’t have any Z-wave devices or even a transmitter.
I have not yet found the need for it.
Maybe this could be the need, but so far I believe the regular relay and WeMos is a simpler solution.

But you are correct. I have no need for the button and can desolder it. Also there is no power supply.
And I can happily place this in either the same box or a new larger box. It doesn’t matter.
It’s hidden in the gigant mess behind the TV.

Yep. If you’re sure the other side is only switching the LEDs. In which case an SPDT (single pole double throw) relay will do.

just yesterday i made a unit which controls the same hdmi switch that u have… what i did was just removed the stock switch and took three wire tappings from one side (which are 2multiplexer select inputs and one ground) and connected a relay to it.and it works fine…even these led works…i u want more help i can give pictures

I gave up on the switch and went for a servo instead.
Works fine also and makes a cute sound when it switches the output

oh good for u …but i feel external servo is overdone for the project xD. …i did it with a normal relay… it can also be done without relay…the multiplexer just needs ground for selection… anyways good to have discussion :smiley:

I couldn’t figure out what the switch actually did.
I tested with the continuity meeter and it just didn’t make sense to me.
I agree that it’s not a good method and a relay is a far better solution.

if u look closely to the thip in splitter its a multiplexer …and the switch is connected to the selector pin of multiplexer… whichever pin is pulled down multiplexer selects that and sends hdmi signal to that port.

Hi did you have a pictures of your project? I trying to achieve something similar. Don’t think I have the exact same switch but has dpdt switch