Imported from GitHub: fabiojmendes/doorsys-hardware · commit fe31e7e · license MIT

Description

Repo for storing the hardware designs for the doorsys system

README

Doorsys hardware

This repository contains schematics, hardware breakdown, and designs for the custom PCB for the Doorsys device.

Earlier versions of this project used a ESP32 relay board and a soldered protoboard. That wasn't very clean as you can see in the pictures section.

Overview

The ESP32 is connected to a relay using GPIO in order to operate the 12v based magnetic lock. A wiegand keypad is also connected to the ESP32 using 2 GPIO ports. A 12v PSU with an external 12V battery was added for continuous operation in face of a power outage. More information, schematics, and PCB design can be found on the doorsys-hardware repository.

Block diagram

Schematics

After transitioning from the ESP32 chip in favor of the ESP32-C3 for better compatibility with rust (ESP32-C3 is based on the RISC-V architecture) a custom board was necessary.

This board design is based on the reference implementation provided by the ESP32-C3 WROOM module datasheet.

Important remarks

• A DC-DC regulator is used to drop the voltage from 12v used by the door lock to the 3v3 used by the esp chip
• The onboard relay is driven by a transistor and contains flyback diodes to manage the voltage spikes coming from the lock
• GPIO 4 and 5 are connected D0 and D1 respectively on the keypad
• GPIO 10 is connected to the relay for door activation
• Headers for the UART and USB ports are available
• Extra GPIOs are available on optional header pins

[!WARNING] Spec wise the ESP32 family is not 5v logic tolerant. But there's lots of chatter on the internet claiming otherwise though. I've been using 5v straight to the GPIO pins to connect the wiegand keypad for a while without issues but caveat emptor.

Printed circuit board

Here is the PCB design:

Pictures

Prototype board using ESP32

PCB fully assembled and migrated to ESP32-C3

New PCB installed and running