Today in the it’s-surprising-that-it-works department we have a ding dong doorbell extension from [Ajoy Raman].
What [Ajoy] wanted to do was to extend the range of his existing doorbell so that he could hear it in his workshop. His plan of attack was to buy a new wireless doorbell and then interface its transmitter with his existing doorbell. But his approach is something others might not have considered if they had have been tasked with this job, and it’s surprising to learn that it works!
What he’s done is wrap a new coil around the ding dong doorbell’s solenoid. When the solenoid activates, a small voltage is induced into the coil. This then gets run into the wireless doorbell transmitter power supply (instead of its battery) via a rectifier diode and a filter capacitor. The wireless doorbell transmitter — having also had its push-button shorted out — operates for long enough from this induced electrical pulse to transmit the signal to the receiver. To be clear: the wireless transmitter is fully powered by the pulse from the coil around the solenoid. Brilliant! Nice hack!
We weren’t sure how reliable the transmitter would be when taken out of the lab and installed in the house so we checked in with [Ajoy] to find out. It’s in production now and operating well at a distance of around 50 feet!
Of course we’ve published heaps of doorbell hacks here on Hackaday before, such as this Bluetooth Low Energy (BLE) doorbell and this light-flashing doorbell. Have you hacked your own doorbell? Let us know on the tips line!
That’s a neat solution.
One of the first projects I built was a copy of this one:
https://frenck.dev/diy-smart-doorbell-for-just-2-dollar/
Connected it to home assistant and have these google homes around my house and in my workshop. It’s great. My google home’s only work for the doorbell these days as so many features have been removed.
I would rather have the pushbutton-doorbell circuit left connected as in the original circuit and sense the doorbell activation directly on the sounder. This way if the ESP or power supply stop working you still have a doorbell.
That’s another option. It wouldn’t help me in my case. I didn’t have a doorbell at all and the notification that there is someone at the door with a picture from my security camera is send through telegram to my phone and audible through the google home’s. I don’t have a gong connected. So if the power supply or ESP stop working, I wouldn’t know.
Nice hack!
That’s said, when I read this:
I thought he was going to use the solenoid to push the button on the transmitter remote… Stealing power from the original one is a much cleverer solution oh yeah and then post
Will tgebregular doorbell work without power rhough?
The ESP failing certainly can happen. The doorbell failing too. So now we’re left with ESP software failing as an additional point of failure. While true, not very likely to be a problem imo … of course you do still control the bell via the esp, not relying fully on HA only …
Why?
Just use relay. Power it from dorbell and connect to button of remote one.
Replace battery every ~3 years.
Works just fine.
That would work. His wired doorbell runs off of mains voltage 220v, there is no transformer (wierd). That kinda relay is special order. He was able to pull this off with stuff everyone has in their parts bin.
He has 220V version on his paper it seems, and yet in India the mains voltage is 230V50Hz not 220V.
He seem to be an older guy though, from the time they had 220V I expect :)
Bit unrelated but inspired by this I measured my own mains, last time I did it was a low 226V (suppose to be 230) and now it’s 234V.
Interesting also to see that the UK uses 230V officially (probably aligned from the times they were EU) but the Isle of Man has 240V. From what I hear the UK has 240V in practice though.
Is a hack.
It’s a very neat solution!
In the “steal energy from the bell” category, I’m charging a capacitor on mine, which powers an ESP-01 for enough milliseconds to send a message to Home Assistant via ESP-NOW.
https://community.home-assistant.io/t/smartifying-a-12v-ac-dumb-doorbell-with-an-esp-01-and-espnow-communication/739835
Project’s been on my low priority queue for a year but at least for sending alerts to my phone, it reliably does so.
I´m Lovin It!
It’s creative. It’s effective. It’s a nice hack. I do like the bypassing of the button, and the elimination of the battery as a maintenance/failure point. (If I were writing clickbait titles, I’d have been tempted to call it a “virtual battery” or other similar nonsensical word grouping. “Coin cell manufacturers hate this virtual battery trick, but there’s nothing they can do about it!”)
Once on the battery-free train, my brain –belonging to a lazy person as it does– would have jumped to directly tapping into the AC that powers the doorbell solenoid. The tedium of winding a coil wouldn’t even have been a glimmer of a thought. That is, unless I was seriously bent on zero modifications to the original system.