Designing a DIY 125 KHz operated deadbolt

A Maker by the name of “jeepdude48507” has designed a 125 KHz operated deadbolt with Atmel’s ATmega328 microcontroller (MCU) under the hood.

As jeepdude notes, the DIY platform is based on a store-bought electronic deadbolt.

“It was battery operated and had a keypad on the outside to allow entry with a user defined code,” he wrote in a recent Instructables post.

“I removed all of the electronics from the indoor housing keeping only the electric motor and mechanism. The mechanism has a built-in clutch that prevents damage should the motor remain on for too long when cycling. My motor is set for a cycle time of about 1.25 seconds.”

Essentially, the project comprises two boards. One houses the ATmega328 MCU with all input / output connectors attached.

“[This board] allows the resonator, voltage regulator, reset switch, power jack and power conditioning in one convenient place. Power for the entire project is fed into this board from a wall-wart (9VDC @ 1A) AC adapter,” jeepdude48507 explained.

“Power before the 7805 regulator is taken to run the motor. Power after the 7805 regulator and filtering is used to power everything else.”

Meanwhile, the RFID reader component is located on the small green circuit board on the lower left end of the controller board.

“It comes with a rectangular coil of wire which is the antenna. I housed it inside a plastic project box,” he added. “Be sure the use the UART type and not the WEIGAND. Only the UART will work with the code I have written for this project.”

Interested in learning more? You can check out the project’s official Instructables page here.

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