Sure. Order some of these. Choose 3v output with pins or w/o, your choice of course. Use the 5v output from any phone charger and you'll get 3v output for the motion sensor.
What you use is really up to what wire you have around to do the job, but here's what I'm using.
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I cut a charger cable in half that came with a phone charger battery pack. I like these because they're intended just for charging, and since it's less expensive to use only two wires, they're already marked for you. You have a red positive and a bare negative wire.
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Using the micro USB side of the cable, I soldered a short length of that cable (cut the micro USB plug off) to two small wires. I use 30 gage wrapping wire which I've had forever. Used a piece for the 5 second hack. Small insulated wire like this comes in real handy. I have this exact same spool in white. That's a good price too. The dispenser is great. You pull some wire out and press a button to trim off a piece. It has a little stripper built in too. Just lay the wire in it and pull, and it nicely strips off a bit of the very thin and flexible insulation.
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I next slid a short piece of 1/32 shrink tubing over one of the soldered connections so they can't short, then another longer piece of 1/16 shrink tubing to join the small wires together, and shrink that. Then a piece of larger shrink tubing, overlapping the 1/16 tubing and completing the junction between the charger cable and small wires. Shrink that with the heat gun.
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Drill a 1/16 hole at the back of the motion sensor housing, right in the center, and feed the wires through. Solder the small wires to the small board at the back of the sensor where the positive and negative battery contacts are soldered on. I left around 4 inches of wire so I could avoid accidentally burning the housing with the iron. Re-assemble the motion sensor, and the short length of charger cable gets soldered to whatever length of cable you have. CAT 3 would work fine. I'm using CAT 5e that's already in place for my Wyze cam and my doorbell button. I'm also using black for everything because I already have black wire up. Obviously you would use white for everything, including the shrink tubing, if that's what looks right on your house.
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On the other end, inside your home, attach the USB A end of the cable to the step down buck and the buck to the cable the leads back to your sensor.