Presence Sensor battery upgrade

Soooo, I’m supper annoyed with the presence sensor battery life… so this is what I’m doing.

Since a CR2032 battery is 3v and ~240mah I figured I could take two AA batteries in series to get 3v and 1900mah capacity. HUGE difference! about 8x the capacity of a 2032 battery setup.

I purchased a few battery cases with leads and project boxes. I’ve already made one for my motorcycle and popped it under the seat. So far, so good. I just want it to last more than 3 months! If the increase in compaticence is even a lowly 50% efficiency gain, which I am guessing it’s far more than that… the thing should last more than a year. If the efficiency is closer to 100% then I can probably expect 2 years out of this thing.

I plan on making 2 more for my car and my wife’s car. What I do is set up a CoRe piston to open the correct garage door (we have 2) for which vehicle is gone when a mobile presence sensor arrives. This way, the gate opens just as we’re going down the driveway for the correct car.

Has anyone else done this? How did it turn out for you?

Pretty simple project, but here it is.

#First, Take the thing out of it’s case, peel the protector off and either use force to separate the plastic shell, or poke the plastic tab.

Take note of the polarity of the battery

Top of the battery is Positive bottom is negative, so the contacts touching those sides of the battery will follow suit.

Red on top, black on bottom of the battery. 2.88V on a 1.5V Battery test means this is one dead battery!

#Test of 2 AA 1.5v batteries in series. 3.15V is good!

#Solder RED to positive terminal and BLACK to negative.
I left the batteries out of the case for this part. This isn’t a soldering tutorial, sorry. You can find plenty on YouTube.

#Test with battery in…
Green! It works! No more button battery!!

I housed the setup in one of these project boxes:

I thought of using hot glue to keep things in place, but things are pretty snug in the box and I don’t think it’s necessary. Feel free to glue if you wish. The battery case fits snug against the screw poles.

I used these for the battery cases:

I put one in the glove box in the cars and one under the seat of the motorcycle. Doesn’t take up much room at all. I’m hoping for about 1 year of life out of the AA batteries.

I just got my new presence sensor from Amazon. (used) Originally I thought ST used a bigger battery in the newer sensor but I was wrong, it’s still a 2032 battery. You could do the same thing with the new one and get 8x battery capacity out of it.


Please post the build list for this.
I know a lot of people are unhappy with the battery life (or the battery holder at the very least since it does break easily) of the ST presence sensor.
I have one but have since gone to using a virtual presence sensor.

I’d be interested to see a picture. I like the idea and theory of it. If your just going to leave it sit in your car / motorcycle . Another option is to buy a DC to DC converter and wire it to your car / motorcycle battery.

I originally used a buck converter to step down the 12v battery to 3v, but it failed and ended up draining the battery. I think for safety sake I want to keep the batteries separate.

I’ll take some pictures when I make the next one.

Plastic Project Box –

5 Pcs Battery Box Holder w Cap On/Off

Previously I used these buck converters but after one failed I think I’ll stick to a direct 3v battery

Buck Converter 24V To 12v 9V 5V 3V

Maybe something like this would be more stable but I haven’t tried it, and after the buck converters failed I feel safer with the AA cell.

SMAKN® DC/DC Converter 12V Step Down to 3V/3A Power Supply Module


Can you upload the photo(s) of the soldering steps?

Sure! I’ll be happy to do that. I didn’t take any photos the first time I did it, but I’ll be making 1 or 2 more this weekend and I’ll take photos.

I’m not very skilled with the soldering iron, but I’ll post my shoddy-ish but workable job.

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Very interesting. Looking forward to seeing the build.

One suggestion would be to use 3V lithium battery in a CR123a 1300mah package or 3V battery in a CR8 2600mah package, you can put the whole thing in the black hobby box and put under the dash. The advantage is that lithium battery tends to last longer

CR123 is a valid idea but the capacity is less and the cost is more than just using two readily available AA batteries. My enloops charge to 2.4Ah, though I’m sure the natural drain on them is huge. I’m just using alkaline batteries for this experiment.

I might make one with a CR123. I have a bunch of those laying around for my motion and tilt sensors anyways.

CR8 aren’t readily available, I’m just trying to stick to cheap, readily available options with a higher capacity. AA are nice because you can’t find a gas station that doesn’t carry them, and there are lots of options (including rechargeable Ni-MH and lithium)

If you’re leaving it in the car, or bike, why not a dc/dc step down with an inline fuse and hook it to the car battery? Then you could pretty much forget about it until you had to replace the battery

Because of this ^

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Missed that. Sorry

No problem! It’s actually a really good idea and I’d like to try it out again. Maybe get a fixed rated DC/DC converter next time.

It’s in my cart, just haven’t pulled the trigger. Separate batteries seem safer after my battery drained.

I’m considering picking up one of these guys:

That’s what I was looking into. I currently only have the mobile phones as presence sensors. I’m trying to see the advantage of dedicated ones.

It’s about logic. The mobile presence sensors are better but here’s my scenario:

I own a large 2-car garage with 2 gates. 1 gate is for my car and my motorcycle, the other gate is for my wife’s car.

When one of the vehicles has left, the presence sensor in the car will set to ‘departed.’

I could be in any one of those vehicles when coming back. In order for the controller to know which door to open when my mobile sensor arrives, it will look at which vehicle(s) are missing.

moto or my car missing? open gate 2, wife’s car missing? open gate 1.

Wife’s mobile presence departed and wife’s car is missing? Close gate 1 because she left it open… and so on.

They work very well in this logic case where you just use them as booleans for your mobile sensor rules.

EDIT: It’s also a really good backup for when my mobile presence sensor doesn’t trigger arrival on my motorcycle and I ride up the the garage. The dedicated sensor is more reliable when it’s in range, and it will open the right gate… although I’ll have to wait a whole ~5ish seconds (boo-hoo) it beats putting the bike down, going into the garage, opening the gate, getting back the the bike and rolling in. First world problems.

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I think @MichaelS has done some battery upgrade to presence sensors… maybe he will share his project.

I will…I have presence sensors that now last over a year using the same idea as @ethayer. I will post a step-by-step tutorial soon with pictures…

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I have similar setup before except I was using 2 D cells and it lasted more than a year for sure. I ended up hooking the srnsor to the car accessory plug and only have power when the car started. I use this to notify when I started my remote car starter.

I made this post the thread topic for visibility since this post is the reason I made the thread.

A week into using these and they’re at 100% battery. I’ll try to post back when they start showing capacity loss.

I’m also thinking of using the new sensor I got to make another one with a 123 battery just to compare usage. Maybe I’ll post those pictures too.


I was also attempting to use my presence sensor for opening my garage door when I arrive home but I would have to sit in the driveway for 30 seconds before it even recognized that I was home. I purchased an Iris Smart Plug that I put in the garage where the garage door opener plugs into to help get a further Zigbee range outside but it didn’t help anything.
I used CoRe to trigger the event when my presence sensor was detected.
Is there anything else that I could try to speed that process up?

I also like the battery mod. May just do that myself as well.

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