I have some ideas about some things that I want to add basic zwave/zigbee connectivity to. Pretty basic stuff like dryer doors triggering lights to come on etc. Yes, I know I could just use contact sensors but I would like to use things like existing door triggers.
I know there are some diy boards out there for this. What is everyone using?
@JohnRob did a cool thing essentially from scratch using dev boards: DIY Ultrasonic sensor with Zigbee Interface - Lounge - Hubitat
@iharyadi has been iterating on an extensible product if you need a slightly higher-level starting point: Hubitat with Homemade Temperature, Humidity, Pressure and Light sensor - Here's a cool thing I did! - Hubitat
The aeotec contact sensors have screw terminals you could wire to an existing open/close sensor.
I used one esp32 (under ten bucks), to read my water meter, make my hardwired smoke/CO alarms smart and hook-up 5 window contact sensors. Works great and wasn't that hard to do (water meter reader was a little tricky, lol). Compare this to the cost of the zwave/zigbee sensors one would have to buy and there is no comparison.
Used this community app: [Release] HubDuino v1.1.7 - Hubitat to Arduino / ESP8266 / ESP32 / ThingShield Integration (ST_Anything)
Best part is, I still have lots of room on the esp32, if I want to add some more devices.
I realized your post said you wanted to add zigbee/zwave connectivity and the solution I mentioned doesn't accomplish that, but as long as the data is reliably sent to the hub, do you care?
Oh not at all. Just some type of connection to the hub.
You’ll find various stuff around the forum. I like the hardware hack too. I sometimes label my posts with [Hack], but that’s often about modding the device itself or building one device from the components of another.
Many like the ESP8266 boards. I’m more of a Zigbee guy. You should also check out @ogiewon ‘s HubDuino
Not sure if you’re looking for ideas or devices to use. Just about any contact sensor will produce a simple input. I’ve used Insteon in the past, Xiaomi Mijia (easier to take apart and reassemble than Aqara), and Ring alarm Z-Wave contact sensors. An easy mod to appliances is adding a 110v relay to create dry contacts to trigger a contact sensor that has wires soldered to either side of its reed switch.
I typically convert these wired in devices to a power adapter so I never have to buy batteries for them again. I use these buck converters with a 5v USB supply.
Solder, shrink tube, a heat gun and patience are the best tools for the job. 
This all sounds exactly like what I'd be after. Diy, low cost, adaptable to my exact use.
Do a search on just about any of my posts. Massive fan of nodemcu's, konnected firmware, massive fan of soldering iron, heatshrink, bits of tape, and cheap reliable off the shelf components.
=p
I have a couple of suggestions you might find useful:
I have used @ogiewon Hubduino and it worked great !
I found the Haas Thingshield replacement and it offered an easy way to communicate with the hub via Zigbee. (look here)
What you see is on the link is:
The green board is a TI cc2530 Zigbee device, mounted on a board with built in antenna. Purchased on ebay for about $6.
The purple board is my version of a kinda universal carrier board. It has 3.3V regulator, filtering for the analog inputs etc.
The green TI board used the Haas firmware which implements analog and digital inputs and digital outputs. It is not modifiable, but very useful.
The purple board is my own design. I purchased them from OSHPark pcb for about $15 for 3 boards. If anyone is interested I will make the design public so anyone can purchase them from OSHPark.
I can also supply the Schematic, BOM and board layout. All required to make the board useful.
I second this. you can do a ton of stuff in arduino, and really the only limitation is your imagination (and the capacity of the board)
Download the Hubitat app
