A great deal has changed in the last two years, as there are now a number of different doorbell options available on the market in both US and the UK. The previous doorbell FAQ had a lot of information on how to build your own device, but that is no longer necessary. I will leave the link to that FAQ at the very end of this post for those who are interested in that kind of maker project.
1) WiFi Video doorbells
Skybell now has an official integration with SmartThings.
It works over Wi-Fi, and is available in both the US and the UK. It also has an IFTTT channel. However, it doesn’t have a separate chime device.
Ring is a different brand with a different look and someone different features. It also has an official integration now, as well as an IFTTT channel, and is also available in both the US and the UK. It typically cost about $15 less than the skybell. For an extra $25, you can get an optional plug-in ring chime device, so it works just like a conventional doorbell in addition to the phone notifications.
And the Kuna lantern does not have an integration, but is still popular with some community members.
For detailed discussion of the pros and cons of each of these, see:
2) Z wave doorbell/sound player (no video)
The Aeotec doorbell is now available in the US, and sometimes available in EU. It costs around $50, considerably less than the video doorbells. It can be integrated directly into SmartThings. It can play up to 99 different sound files, and you can upload your own. these files can be triggered by any SmartThings event, so you could have one sound for the front door button being pressed, a different sound for the back door opening, a third sound used as a laundry announcement, etc. there are two different custom device type handlers available in the community, both approved by Aeotec. They have somewhat different features, and both are popular.
You can also read more about how to get a chime or voice announcement effect when a door is opened in the community – created wiki:
This device comes with its own button, so you can just use that as a doorbell. Alternatively, you can wire an existing doorbell button to a dry contact device inside the house and use that.
The only problem with this device is that it is very fiddly to get paired the first time. This is why it has so many low reviews at Amazon. But once you do get it paired, it works fine.
3) (US) zwave doorbell detector wired into existing doorbell system
In the US, Nexia makes a sensor which is specifically designed to be wired into an existing doorbell system. It greatly simplifies the process for this kind of retrofit.
Amazon now carries it for about the same price as the Aeotec doorbell. The Aeotec gives you the ability to have custom sounds, as well as different sounds for different events. The Nexia just retrofits a single existing doorbell. It doesn’t have its own chime. Some people even use both, using the Nexia to capture The existing doorbell while retaining the current button hardware, but then adding additional notifications and sounds for other events from the Aeotec.
There’s a community created device type handler for it:
4) hacking a contact sensor (UK version)
Vesternet has a good article on hacking a contact sensor. However, you may need a custom device type handler in order to change the parameter of the sensor to report appropriately.
5) using an Amazon Dot as the speaker and an Aeotec Panic Button as the button. Both of these devices are available in both The US and the UK. Prices will vary, but typically you could get both of them for just under $100 or £100. The button is easy, it just works like a button.
And as of November 2019, the echo now offers a chime sound in an echo routine.
6) The old 2015 FAQ
The old 2015 doorbell FAQ has a lot more information on hacker approaches. It’s just now there are so many purpose – built devices, there will be fewer people interested in taking that option.
7) Apartment buzzers and other types of doorbells
There is also a quick browse list in the community – created wiki for project reports on doorbells. This includes some of the options discussed above, but also some more unusual projects like apartment buzzers and a networked welcome mat.