The 3d printed parts are a container for the ZOOZ zen17 Universal relay with a barrel jack plug and rj11/phone jack ports for connecting to Alimed sensor pads. This design requires no soldering, just crimping.

Zen 17: https://www.getzooz.com/zooz-zen17-universal-relay/ 

 Alimed toilet sensor: https://www.alimed.com/alimed-toilet-pressure-sensor-pads.html (tested and works)

Alimed corded sensor pads for bed and chair https://www.alimed.com/alimed-sensor-pads.html (ordered chair version for testing. bed version untested)

(Note: the above sensors have warranties such as 13 day, 3 month, or 6 month warranties. I am unsure the difference it makes in actual quality or if its more abstract to force replacement. I will see how long my sensors last. With this design, sensors should be very easy to replace)  

This is for the purpose of making a set of sensors that connect to a smart home system like Hubitat that will then flash smart lights and ring a doorbell to warn me that my grandfather is getting up from his chair/toilet/bed but they could easily be used as presence detectors.

Alimed makes medical Toilet, Bed, and Chair sensors that terminate into rj11 jacks. While rj11 jacks have 4 wires, the 4 wires twist into two pairs of wire inside the sensor in-between a piece of foam that becomes conductive when it has force applied. This turns them into basically a dry contact switch that the zen17 can read. 

I used the rj11 port linked below and twisted the yellow and green together, and the Red and Black together and crimped them together using a ferrule Crimp. The yellow/green wire is then tightened to the SC port and the red/black wire is put to the C Port. From there, you can connect the sensor directly to the sensor box, or use a rj11 connector and additional phone wire to make the sensor reach longer. In my setup, I added 50ft of flat telephone wire and worked it into the gap between the carpet and the wall. 

For power, I used a basic 12 volt barrel power supply with a 2.1x5.5 connector and added a threaded female 2.1x5.5mm barrel jack that is linked below to the box for power. 

rj11 port: https://www.amazon.com/uxcell-Female-Connector-Telephone-Connectors/dp/B01HU7BX42/ref=asc_df_B01HU7BX42/?tag=hyprod-20&linkCode=df0&hvadid=692875362841&hvpos=&hvnetw=g&hvrand=7295142863279773723&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028035&hvtargid=pla-2281435177898&psc=1&mcid=d6f2e62679313fdb8c79b683134f8d7f&hvocijid=7295142863279773723-B01HU7BX42-&hvexpln=73 

threaded female barrel jack with attached wires: https://www.amazon.com/Tegg-Connector-Dustproof-Water-Proof-5-5x2-5mm/dp/B07MLQCDN3/ref=asc_df_B07MJ4YWQ8/?tag=hyprod-20&linkCode=df0&hvadid=692875362841&hvpos=&hvnetw=g&hvrand=2613451738297306162&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9028035&hvtargid=pla-2281435178098&mcid=919be47d05333fb2951e72ec8c8f7a26&hvocijid=2613451738297306162-B07MJ4YWQ8-&hvexpln=73&th=1 

Hubitat setup (should be similar to other smart homes)

Go through the standard z-wave device pairing outlined in the manual. 

In the settings of the device, set “Input Type Relay” 1&2 to dry contact and leave “Input Trigger for Relay” 1&2 to enabled.

This will make it so the Relay turns on when pressure is applied to the sensor. This wont do anything if you don't have anything electrically connected to the those relays, but it will show in Hubitat that the Relay is on. SC1 is relay 1. SC2 is relay 2. The relay names will be a long weird name after setup like “Switch Binary [e759f5d6001300] - Relay 2” I would rename this.

Using Basic Rules, you can setup up a variety of commands. in my setup, I have it setup that it triggers my alarm system when the Relay is off (pressure is removed) 

you could also use them as presence sensor, so that when the relay is on, lights don't turn off or other items.

There is a roughly 1.5 second delay between pressure being removed and the hubitat actually sending out commands (alarms going off) and could be longer or not even happen if there is a local radio interference. This is something to be cognizant off as that could be a problem. you could also wire a non-smart alarm or light directly to the physical Relay. This will eliminate the risk of radio interference and delay. I personally did not go this route and used the hubitat sensors. 

For the box itself. I used M3 threaded inserts and M3-10 bolts to hold the lid down. I used ABS but really any material should work. I used 2 walls, 10% infill. 

Also shoutout to ZO0Z support for helping me with this design. I originally bought a sensor that did not work in this application and not only did they give me a 15 dollar discount on this sensor, but their engineering team also bought the toilet sensor and tested it with the Zen17. They confirmed it worked and gave me the above diagram. Those guys are great.