Hi. I'm using the Insteon hidden door sensor (HDS) in several locations but after 4 or 5 years, I'm tired of replacing batteries. The HDS is rather unique and handy for some applications... in particular physical pressing of the button to get positive and verified indication of door deadbolt locking and also sliding glass door latching. These are applications where a magnetic open/close sensor would be difficult or impossible to implement.
So, I'm left with 9 lock sensors in my home (HDS sensors) which will still be needing batteries. ... oh yeah, we'll see about that lol.
The HDS devices are powered by a single AAA 1.5V battery. I've tried using Eveready L91 style lithium cells (AAA) and yes, they last about twice as long and yes they are expensive... and yes, they still drain. So my idea is to independently power HDS sensors as I remodel the home, hiding sensor wires and power wires in CAT5 cable in the moldings. Currently I'm doing my master bedroom.
I took one of the dead HDS sensors from past experimentation, and looked at the electronics using a 16x loop and some bright lights... paying particular attention to the PCB trace wiring and components.. I found that the HDS is powered using the TI TPS6122x "Low Input Voltage 0.7V Boost Converter" (or some look alike part) which takes the 1.5V battery, and boosts the power rail up to a more standard 3.3V for use by the sensor circuits. The battery voltage can fall to 0.7 volts before the HDS quits. too. soon.
Anyway, the reason all of this is important to know, is that when you power devices from CAT5 cable, you have to consider the power cable losses. For AWG 24 wire, you're going to lose about 0.6 volts per 30 feet of wire... 30 feet of power... 30 feet of GND... so chop off more than 1V right at the start. Obviously a 1.5V power supply would be problematic. However A) not all of my runs are 30-feet and B) this sweet little Boost Converter devices will handle anything from -0.7V to 5.5V at it's input pin, a useable 0.7V to 5.5V... 7.5V max (momentary only). This tells me that I can use the 5V DIN rail power supply which I happen to have built into my master bedroom control chamber and run 5V to all 3 HDS sensors which are a part of the master bedroom suite. This should give me a nominal 3.8V after wire losses depending on wire length. Using a 3.3V power supply (nominal 2.1V after the wire losses) would work too but would rather use what I've got.
I'm anticipating that the "Low Battery" messages from the HDS's will simply be few to none. I'll let you'all know if there are any hitches with my approach. I'll be doing this mod before the end of January 2018 (this month).