Hello, and thank you in advance.

I’m making a privacy friendly “ring” cam/doorbell following this guide: https://tristam.ie/2023/758/ which has been great, but requires running a micro-usb cable down to the doorbell for power. I’m hoping to improve on this by using the existing doorbell power instead.

The problem is that I’m a DIY electronics noob and I can’t create a mental model for how it should all work. The picture I attached is my existing doorbell wiring scheme, which is as simple as it comes. I totally get how this works. Pressing the doorbell completes the circuit and makes the bingbongs. But this will have to change so the new door cam gets power full time. Ideally without the chime bingbonging full time.

In addition to the ESP-32CAM, button, ring lights, etc., I also bought these: https://www.amazon.com/dp/B079FJSYGY which I thought might be needed to complete the circuit?

I measured the voltage after the transformer and it was around 18 volts, but maybe this is AC and I want DC?

Generally I don’t know where in “the loop” to put things. Also, all the existing components are very far apart from each other, so I would love a solution that doesn’t involve running any new wires through the walls.

Any help is appreciated. Thank you!!

xoJimbabwe

  • Jimbabwe@lemmy.worldOPEnglish
    1·
    7 months ago

    I couldn’t remember if it was AC or DC, but you’re almost certainly right that it’s stepped-down AC. I just went and checked and there’s no light on the button, so unfortunately no bonus parallel always-on power source to tap into. This is my dumb guess about how this all could work, but there are some question marks. Does this seem kinda correct though?

    • ch00f@lemmy.worldEnglish
      9·
      7 months ago

      Your drawing is a little confusing. Here’s what you need:

      There’s nothing special about a setup with a light in the button. It’s literally just an incandescent bulb across the button. If you connect your circuit across the button terminals, it’ll work fine.

      The 4 diodes in a loop is a “full bridge rectifier” that gives you DC from AC. The 5V regulator could be something like an LM7805.

      The “large capacitor” is to keep power applied while the button is pressed, though you might be better off in that case with some small onboard battery. You just have to make sure that your battery charging circuit doesn’t draw too much power.

    • Limonene@lemmy.worldEnglish
      4·
      7 months ago

      Remember that voltage is measured across a pair of wires, so you can’t power the chime with only a single wire. That’s part of what makes this difficult – these doorbell systems only have the bare minimum of wiring in them. Powering the camera and the chime in series with each other is quite difficult. I think a lot of these things just accept the short circuit, and use a battery to power the camera while the button is being held.

      Here is what I was proposing, and I think what ch00f was also proposing. Replace “5VDC power supply” in this diagram with “a full bridge rectifier and a bunch of caps” in their description, and also note that your camera probably requires a well regulated 5VDC supply.

      • Jimbabwe@lemmy.worldOPEnglish
        3·
        7 months ago

        Awesome, thank you both. This is more complicated than I thought, so on the plus side I don’t feel as dumb as before.

        Maybe i’ll just ditch the dinky chime I have and setup some alert automations or something. In that case, I could just connect the two chime wires to create a closed loop, then replace the transformer with a 120vac outlet plug, plug in a generic 120va -> 5vdc power supply, chop the two output wires from the power supply and connect them to the existing doorbell wires. And violá, 5vdc delivered right to the front door? Is this plan insane?

        • Limonene@lemmy.worldEnglish
          3·
          7 months ago

          Actually, I think that’s a really good idea. Just be aware of possible inductance in the long wires from the transformer area going to the camera. Putting a large electrolytic capacitor next to the camera should fix that.

          As for your bell, there are dead simple systems that use a battery-powered stick-on button with a transmitter, and a chime/receiver that plugs into a wall. If you want to be fancy, you could find a way to power the transmitter with that 5VDC, in parallel with the camera… or you could just keep it simple and use the battery that comes with the button. They last near forever.