Homemade Battery Eliminators

I wanted to share this project with the community in case you have similar challenges. I do NOT however want to get into a debate on the cost of batteries vs the cost of converting sensors to batteries which has been debated several times on this community; I realize this is more expensive. But I value my personal time and this has and will save me there.

Several years ago when still using the ST platform, I explained how I converted a few sensors from batteries to USB power:

Make a battery powered sensor run on USB

Recently I wanted to do the same to several Iris Motion sensors in my home that are a pain in the butt to get to given 10 foot ceilings and furniture underneath. Accessible attic space is above these 3 motion sensors so it was easy to run wires. The challenge:

  • I wanted to be able to easily pop out the "battery" in case I needed to reset the motion without having to go into the attic.
  • I needed to conceal the wiring for spouse approval
  • My original ST solution which involved putting the step down voltage regulator inside the sensor which doesn't allow for either wants above.

I was inspired by this "Battery Eliminator" post and came up with a solution. I took one of my CR2 batteries to my local box store and purchased a dowel with a similar diameter, some small screws, and leveraged a box of 2 conductor security wire that I already have. Below is the final product. Differences from the Instructables Article:

  • Instead of a selectable DC power adapter, I am using a 5V to 3.3V Step Down Voltage Regulator found on Amazon. This is the product I had mentioned in my ST article years ago.
  • I used a hack saw to cut a small cross cut on the dowel so the wires leading to the screws can be pushed into it. My OCD didn't like the pictures in the article. :crazy_face:

My battery eliminator:

Drilled hole into top of motion sensor for wire:

Battery eliminator installed into Iris Motion:

Final Installation:

Over the weekend, I also installed one into a Sage Doorbell sensor that I put into my crawl space by the doorbell transformer:


Nice... Never been a fan of all these batteries... That’s one reason I like the aeotec multisensor and now the inovelli 4in1 they both have micro usb ports to power them... I am planning on using an industrial 5V supply to run them all off of a single point through the attic..


I'm going this route


That looks great! I've soldered the regulator into the unit and went out the back but to your point easier to reset this way. Where does your regulator live? By the usb charger?

On the other hand I have the usb end plugged into some outlets with usb ports in my closets - an external regulator would look kind of messy unless I had some sort of streamlined barrel shaped connector enclosure on the cable itself. I've done the plastic project boxes in the past but they are kind of bulky.

Make sure the USB chargers you are using are quality ones with a real UL listing. Years ago I bought some cheap Chinese ones, and 3 out of 5 ended up eventually melting. You don't want that, especially if they are in a wall or attic.


Of course you could always plug your usb charger into a smart plug and control resetting the device that way... Inception - HE style.. :rofl:


Yeah it’s unfortunate how few devices there are with usb power. I get it as it adds cost and sometimes limits where you can install them. In my master suite I have a dual usb brick powering two motion sensors.

Good for and great find. That solution is very similar but my point in this thread is the use of dowel as battery :grin:. That idea would still work for your solution.... Otherwise you will need to figure how to make those large alligator clips fit into the battery compartment.

They are in attic by the receptacle and USB brick. I cut off the end of a few usb cables to make this work. Given attic space I wasn’t too concerned about the look and feel there so they are stuffed by insulation.

Great point and that is where my white Apple chargers have come in handy that I don’t use from iOS devices we have purchased over the years.

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How much power is needed for the alligator clip thing? Is 500ma okay or does it need 1 amp?

I'm running a Visonic MCT340 contact sensor on a .7 amp power supply and an Iris V2 motion sensor on 1 amp, with no problems. I figure these sensors don't draw much and it would be a good place to get rid of some of the low-amperage power supplies I'd collected.

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Got theseHere and they seem to work since most of my motion sensors aren't near power. Probably will use a combo of your guys method solder a wire through but I will use the usb thing while cutting off the alligator clips. thanks for the help! Makes smart junk much less of a hassle.