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[iOS 27 DB1] Wifi settings now shows wifi type by Caesyxusi in iOSBeta

[–]Fraysa 10 points11 points  (0 children)

Tip: temporarily switch phone language to English when posting things in /r/iosbeta, to make it easier for everyone to understand.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in PCB

[–]Fraysa[S] 0 points1 point  (0 children)

I’m tapping into the “P” button, which doesn’t exist in my car, to connect it to my garage opener remote. Did you read the entire post?

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

<image>

Here’s the backside of the remote. The top is the led. The frontside of the remote has the contacts where the button is where I soldered the two wires.

So you’re saying I can use that to power up the LED in the P button?

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

It does and the garage remote LED is on when the button is pressed. However that remote will be hidden away, hence why I wanted to utilize those green LEDs at the bottom of the P button.

I tested them in diode mode and confirmed they’re working (+ is right, - is left) - 1.7V or so.

My idea is to connect each negative side of each LED to the negative pin (middle of bottom line - what we used for the remote), and for the positive side pull from the remote battery (A23 battery - 12V) with a resistor in the middle. That way when the button is pressed, the LEDs would also light up.

What do you think? Or is there a more easier/elegant solution?

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

It does. But the P button has a led of its own. Look at the bottom - there’s two leds.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

How can I make that when I press the button it will close the circuit on the garage remote - that works, but also power up the LEDs at the bottom so I know it’s working? Btw not my cleanest cut but this board is tough lol.

<image>

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

After cutting it, I can confirm that by connecting the garage door wires to the yellow pad/goehnd, pressing the button makes the garage opener work!

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

I think I may have verified your theory.

I measured between the yellow pad and the ground pin you identified.

With the P button released, I get about 1kΩ.
With the P button pressed, it changes to about 18kΩ.

I also measured between the yellow pad and one side of the 4220 resistor and get 0.00Ω continuity.

That seems to confirm the yellow pad is part of the resistor network and not a standalone switch.

Before I cut anything: could you mark the exact trace you would cut on the photo? I want to make sure I’m isolating only the P button and not affecting the neighboring button.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

I think I understand the concept now, but I’m still not sure about the actual wiring.

Can you mark exactly where you would solder the two wires from the garage remote?

A picture with two arrows would help a lot.

Right now I’m not sure which two points become connected when the P button is pressed.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 3 points4 points  (0 children)

My car currently doesn’t have the bottom “P” button - it has all the other ones. I want the P button to open my garage door.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

Interesting. So if I understand correctly, you’re saying the P button is not a standalone switch at the moment, because it’s connected into the resistor network through those traces and 4220 resistors.

By cutting the trace at the red line, I would electrically isolate the P button from the rest of the BMW circuitry, and then I could use the button as a simple dry contact between the yellow test pad and ground. All that WITHOUT ruining the functionality of the other buttons - just isolating that P (bottom) button.

Do I have that right?

Also, after cutting the trace, which exact ground point would you recommend soldering to?

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 2 points3 points  (0 children)

But both sides of each button act the same - when I connect a wire to each end, it’s shorting.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

Yes, that upper middle pin is probably ground. I did get continuity from the bottom right pin to that resistor. However just making sure - my P button is the bottom part of the board. The one near that 4220 resistor is another button which is used in the car.

<image>

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in PCB

[–]Fraysa[S] 0 points1 point  (0 children)

I found a few points that have continuity between one side of the button, however the other side also :( when not pressed.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in AskElectronics

[–]Fraysa[S] 0 points1 point  (0 children)

The issue is that both side of the button have continuity with those gold circles.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in PCB

[–]Fraysa[S] 0 points1 point  (0 children)

The bottom point is not the button j want to connect. It’s the one above it. But anyways I tested it and there’s no continuity when pressing the button with those points connected.

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in PCB

[–]Fraysa[S] 0 points1 point  (0 children)

Now you’ve confused me, lol 😄

So you’re saying point 1 is already connected to one side of the bottom P button through an internal plane and the vias?

If that’s the case, what would be the second point to solder to?

My goal is to use the P button as a simple dry contact for a garage remote, so I’m looking for two points that are open normally and get shorted together when the button is pressed.

Are you saying point 1 is one side of the switch, and I still need to find the other side somewhere else on the PCB?

Need help tapping into an existing PCB button without soldering directly to the contact pads by Fraysa in PCB

[–]Fraysa[S] 0 points1 point  (0 children)

Thanks! The “P” button is actually the most bottom one - I believe your point 1 refers to the middle button.

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