Do you mean that have dry contacts? Because “input from external sources” could mean a lot of different things.
If you just mean have dry contacts, then one model of the Fibaro door sensor is popular for this purpose in the UK.
And there are even several devices available in both the US and the UK which are made specifically for this purpose:
1)
Fortrezz Mimolite
The original, was very popular, but the company has since been bought by one which is targeting professional installers and it is becoming hard to find for DIY
Aeotec Door Sensor Pro (The “pro model“ has Dry Contacts)
This replaces their earlier dry contact sensor. Available in both US and the UK. Uses the series 700 chip, so should have excellent range and battery life. Make sure you get the one that matches your hub frequency, so don’t try to use a US model with a UK hub or vice versa.
Aeotec Zwave ZWA008 3 in one Door Sensor with Dry Contacts
https://www.amazon.com/Sensor-Window-Z-Wave-Enabled-Required/dp/B08LDJJWSY/
- The Nexia doorbell sensor although made specifically for doorbells, is also designed for this purpose, but is only available on the US frequency.
Fibaro also makes a “universal sensor” for this purpose, but it is limited to lines with a maximum of 30V . Still, it’s good for some low-voltage projects like some gate openers.
available in the UK zwave frequency:
Or in the US:
Here is one community-created custom edge Driver for it:
(EDGE Driver-Mc): Fibaro Smart Implant Mc
- The Ecolink door sensor is only available on the US frequency, and is a popular choice. However, be aware that some people have reported that they received individual devices that didn’t have the dry contact screws inside, even though they have the same model number. It’s not clear whether those were different production runs or maybe even counterfeits. (it’s been known to happen.) so I would only buy these from someplace with a good returns policy just in case you get one of the ones without the contacts.
It should work with the following edge driver:
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Everspring has a similar model to the eco-link available in the UK. Try Vesternet for that one.
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And new for 2020: Zooz has a very interesting zwave S2 module for the US with 3 dry contacts. Zooz provides an edge Driver, for it linked from the product page.
(Popp has announced a similar design for the EU only, the SA01, but while it has been certified I have not yet seen it for sale anywhere.)
2022 update
Zooz now has several models that have dry contact terminals, all at very good prices and with the newest Z wave features. But only available on the North American frequency. These make a good substitute for the old Mimolite model as long as you are in the US, Canada, or Mexico. Zooz provides edge drivers for most of its devices.
- Develco/Frient Zigbee IO module with 4 dry contacts. Available in Europe. @Mariano_Colmenarejo has a very nice custom edge Driver for This, which exposes all 4 dry contacts for use in smartthings routines.
Custom edge driver
(EDGE Driver-Mc): Zigbee Frient I/O Module Mc
- Shelly’s new UNI relay is a really interesting device, probably most similar to the old fortrezz units, but uses Wi-Fi. It’s hard to find in the US, but widely available in Europe. You can also get it shipped to the US by the manufacturer.
https://www.shelly.cloud/en-us/products/product-overview/shelly-uni
@taustin has an edge driver for this and many other Shelly models:
Edge Shelly drivers for Gen1 and Gen2 Devices
If you don’t have a smartthings/Aeotec hub, and want to use the official cloud to cloud integration, check with Shelly to make sure this model is included.
- Shelly 1 PM is a WiFi relay with dry contacts. One model is UL certified, which I would highly recommend for this use case. Available in several regions.
https://www.shelly.cloud/en-us/products/product-overview/shelly-plus-1-pm-ul
@taustin has an edge driver for this and many other Shelly models:
Edge Shelly drivers for Gen1 and Gen2 Devices
If you don’t have a smartthings/Aeotec hub, and want to use the official cloud to cloud integration, check with Shelly to make sure this model is included
- If you are looking for something specifically to use with wired security system sensors, like wired window sensors that run to a central panel, there is a system for doing that called Konnected Which has been very popular for this purpose. Contact their support for more information. They do have a cloud to cloud integration, which works with the 2023 smartthings architecture. No SmartThings/Aeotec hub required.
Other kinds of input
On the other hand, if you mean to include devices that can handle an external probe, such as for temperature or moisture, there are several but they are very different from the ones with dry contacts.
- The Fibaro. RGBW Controller can accept input from four different analog sensors, and is popular for greenhouse operations. This was popular in the past, but I’m not sure if it still works with smartthings in 2023. It’s no longer on the official compatibility list. Check the forum to be sure.
https://www.thesmartesthouse.com/products/fibaro-rgbw-controller-fgrgbwm-441
Or see their “universal Sensor,“ number four above.
Also, the Shelly devices 8) and 9) above can be connected to a ds18b20 probe for temperature monitoring.
There are other devices that can accept input from a single probe sensor, most commonly temperature. But before I start listing those, I wasn’t sure if that was what you were interested in. 