smart Doorbell Sensor

How to Make A Cheaper Smart Doorbell Sensor in 10 Minutes (Z-Wave, Zigbee, You Name It!)

In Home Automation by JodyLeave a Comment

Having a hard time finding a doorbell sensor for your home automation system?

No worries, you can easily make your own by following this guide.  Read on to find out what components you’ll need and how to tie it all together.

If you’re in a rush, use the links to jump to the section you’re interested in:

How would I use a doorbell sensor anyway?

In case it isn’t obvious, let’s spend a few seconds discussing how a doorbell sensor might come in handy.  I can think of a few reasons that I really like mine:

  • It’s a reliable way to tell when you get a package dropped off. It’s better than a motion sensor since it doesn’t have false alarms from birds and sun like a PIR motion sensor.
  • It’s good for knowing when people visit your house while you’re away.
  • I always get notifications on my phone, even when I’m outside in the back yard or somewhere else I may not hear the doorbell.

What do I need to make a doorbell sensor?

Assuming you have a hard-wired doorbell with an electromagnet (most people do), this is a short list.  If you’re not sure, just compare your doorbell to the installation pictures below.

Here’s the list (links are to Amazon, don’t cost you anything, and are the digital equivalent of a quarter in my guitar case):

  • Insteon, Zigbee, or Z-wave door sensor with external inputs (the Schlage RS100 is ~$25 on Amazon depending on when you catch it)
  • A magnetic reed sensor (preferably with some wire and flying leads or screw terminals and a housing) – I went for this Ademco unit
  • Wire (feel free to steal from old electronics, AWG 24 would be fine if you’re buying)

It’s as easy as that!

If you can’t find a sensor that will accept external connections, any door sensor with a detached magnet will work. Just find a way to mount it close enough to your doorbell to trigger the relay switch inside of it. Unfortunately, a lot of door sensors are just too large for that.

The SmartThings multisensors are smaller, but they are expensive if you don’t want the temperature and vibration functions. The Nyce sensors may work in your doorbell, just be sure to measure before purchasing.

OR, you could take the cover off of any door sensor and hook a wires up to either side of the relay inside of the unit to bypass it with the one that you buy and place inside of the doorbell. If that’s not clear, just hit me up in the comments for questions.

For the magnetic reed, you can pick up a pack of sensors with axial leads, but these are usually in glass tubes that are very fragile and aren’t designed to be used in a free-floating installation.  So, save yourself time down the road and buy a packaged sensor.  If you really want to go cheap, you could use hot glue or RTV to create a more durable housing for an axial reed relay.

reed switch or reed relay

Author: André Karwath

Of course, this assumes that you already have a home automation hub that you’ll use to pair with the sensor that you purchase.  If not, you’ll need a hub or something like a Z-Wave stick to plug into your Raspberry Pi or a PC that stays on all the time.

Here are some reviews if you’re in the market:

If you’re handy with software and technology, HomeAssistant is open source and has great momentum. I write software at work, and prefer to change things up at home and use SmartThings currently.

How to Build a Z-Wave Doorbell

Once you have what you need, tying everything together is pretty simple. Here’s the play-by-play:

  • Pair your sensor to your home automation controller using the included instructions
  • Connect the leads of the reed sensor the terminals on your door sensor (now’s a good time to get a magnet and test your setup)
  • Take the cover off of your doorbell
  • Install the reed sensor as close to the coil of the electromagnet as you can (the thing with the wires going to it)
  • Find a place to place your door sensor and replace the cover
  • Test it out!

Here’s what mine looks like after installation and testing:
Doorbell Sensor after installIn my testing, it wasn’t even that critical to get the reed sensor close since they are pretty sensitive. Within half an inch or so should do it.  Of course, your mileage may vary depending on the strength of the magnetic field created by your doorbell.

What are the best smart doorbells that I can Buy Off the Shelf

This is a pretty easy build, but I understand if you’d rather not even think about it. There are some options for those that don’t want to think about connecting wires and such.

I’ll try to keep this updated as new products are released.

Z-wave Doorbells

For Z-Wave doorbells, check out Aeotec and Nexia’s offering.

Zigbee Doorbells

In short, there’s no off-the-shelf Zigbee doorbell yet.  And, the only other option out there is significantly more involved that what I’ve shown you here.

But, it’s a solid guide that you could use to fulfill your Zigbee needs in other ways to, using a hacked Cree Connected bulb’s IC (Atmel SAMR21) to interface to your sensors.

WiFi Doorbells

If you don’t want to spend $250 and get a camera too, there just aren’t any good WiFi doorbell options.

Insteon Doorbells

Sorry, there’s no ready-made solution here either.  Your only option is our suggested build above.

Wrapping Up Your Smart Doorbell Build

Now, it’s just a matter of setting up rules and automations that will leverage your new sensor.  For me, this was just a matter of making sure that we got push notifications on our phone whenever someone pushed our doorbell.

Once you’re done, the hardest part about this whole setup is getting back to the door before the UPS guy speeds away in his truck with a package that he didn’t give me a chance to sign for.

If you need any help, drop a line in the comments.

I hope I saved you a few minutes. Be sure to sign up for more security tips and tricks if you found this article helpful.

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