The Ring doorbell is a pretty simple and useful product. I was wondering: how does the Ring doorbell get power without activating the chime? As far as I know, a doorbell works by shorting two wires when the button is pressed and causing the chime to chime. But, with the Ring doorbell, the two wires are always connected because it needs to be always on. So why doesn't it ring the chime if the two wires are always shorted? I know there is "Ring Power Kit" you connect at the chime. You can see pictures of it here.

I am a rookie and I just started out playing with Arduino and ESP chips. I hope someone can explain this to me.

I am asking this question because I want to make a smart video doorbell with an ESP32 connected to a camera. I want to know how would I power the ESP32 without shorting out the two wires.


1 Answer 1


tl;dr version: Ring wires across the doorbell switch pair and sources power from the bell transformer.

The switch wires provide Ring with low-current 16~24V AC through the bell coil. Ring's current load is low enough that it doesn't trigger the bell. This small current is (usually) enough for Ring to keep up the charge its local battery. More about ‘usually’ below.

Ring's power management works as follows. Most of the time, Ring is in a deep sleep mode and uses very little power - a trickle for the battery, and a small current for the passive IR sensors and a small low-power MCU. During deep sleep, the camera and radio are off and the MCU is monitoring the array of IR sensors on the front. When the MCU senses motion on the IR, it wakes up the rest of the system and starts recording / transmitting the potential porch pirate's misdeeds.

If you're lucky enough to have a legit visitor instead of a porch pirate, they will eventually press the doorbell button on the Ring (unless they're millennial or Gen Z, in which case they will text you. Whatever.) The button press makes Ring short across its power feed to ring the bell, cutting off its power. But no worries: Ring uses its battery to power itself even while the doorbell switch is pressed, so you can see your visitor staring alternately at their phone and their shoes.

And... the ‘usually’. The new Ring Pro version seems to use more power, more than can be reliably sourced through the bell coil in some cases because of the coil DC resistance. The Power Kit you show is designed to shunt some additional current past the doorbell coil to supply the Ring Pro connected at the door. It seems complex - would be interesting to analyze it.

  • \$\begingroup\$ So the ring is trickle charging the battery and since the doorbell is using really less current the doorbell doesn't ring? how small of current is it using? \$\endgroup\$ Jul 17, 2019 at 10:48
  • \$\begingroup\$ By "shunts some current" you mean that it decreases the current so it can power the ring but not ring the chime? \$\endgroup\$ Jul 17, 2019 at 11:32
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    \$\begingroup\$ It bypasses some of the current across the bell coil, yes. It may do more than that - it looks like it’s rectifying the voltage to DC also. \$\endgroup\$ Jul 17, 2019 at 13:18
  • \$\begingroup\$ In the website I linked in the question, he says that he also sees a solid-state relay too. Does the relay control the chime? \$\endgroup\$ Jul 17, 2019 at 13:47
  • \$\begingroup\$ can you read my edit and provide me with some information on how you would tackle this. \$\endgroup\$ Jul 17, 2019 at 14:27

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