Make a battery powered sensor run on USB

Wiki Projects & Stories
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I have a few sensors in locations near a receptacle but yet I continue to change batteries. Well no more! After reviewing several YouTube videos and doing a little research I found a small device a little smaller than a CR2 battery that converts 4-12V DC down to 3.3V DC which is the equivalent to 1 CR2 or 2 AAA batteries. I converted my first sensor today and thought I would share.

Here is a good video tutorial. I ended up getting a slightly different power module than the one mentioned in the video since this one has a higher range of input voltage. Plus it is smaller in size too.

This power supply module to down-convert the power:
https://www.amazon.com/gp/product/B01CONBSV0/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

First I hooked up a few wires to the power module that I hook up to a USB wire. I also hooked up a small wire to the positive pin of the 3.3v output so I can run it to the positive terminal of the sensor. I left the 3.3v negative pin alone as I will come to that in a bit.

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I decided to put the power supply module inside my sensor where the CR2 battery would normally be. To do this I drilled a small hole to run the wire.

IMG_5758.JPG3024×4032 1.73 MB

Next I placed the power module inside the battery slot of the sensor:

IMG_5754.JPG3024×4032 1.91 MB

Then I put the sensor back together:

IMG_5757.JPG4032×3024 2.47 MB

Since the 3.3V output is beside the negative terminal of the sensor, I bent that pin so it touches it. I then used the small wire coming from the positive pin and tuck it behind the input wires so it touches the positive terminal. I purposely did this so I can easily convert this sensor back to battery if I ever want to.

Then I added a few pins at the end of the wire hanging out so I can easily disconnect it from the USB wire. Then I installed the sensor back in my attic and plugged it in!

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The power module has an LED on it so that is the red light you see within the sensor. That is it! No more changing batteries. I plan to do this to a few other sensors in my house as well.

In case you are interested in using the same type of male and female pins I used, here is a picture of the kit and crimper needed. I bought a kit since I have been doing other types of Arduino projects as well.

IMG_5759.JPG4032×3024 2.48 MB

https://www.amazon.com/gp/product/B014YTPFT8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00YGLKBSK/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

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3

~Two Years Later~

Just wanted to say thanks for this tutorial. I’ve converted one of my Iris motion sensors and it’s such a relief. It seems to respond even faster than it did with battery too. Very easy and inexpensive to do. I plan to convert the rest of mine and have that many fewer batteries to change.

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