We're still working on the hardware documentation. The following parts are suggested for development and experimentation, but not necessarily for deployment.
You need a raspberry pi, of course:
CanaKit Raspberry Pi 3 B+ (B Plus) with Premium Clear Case and 2.5A Power Supply
$54.99
Electric Strike Lock, ZOTER Narrow Type Electric Door Lock for Home Office Wood Metal Door NO Mode Fail Secure DC 12V Access Control
$26.99
https://www.amazon.com/gp/product/B0105WEFBW/
SunFounder 2 Channel DC 5V Relay Module with Optocoupler Low Level Trigger Expansion Board for Arduino UNO R3 MEGA 2560 1280 DSP ARM PIC AVR STM32 Raspberry Pi
$6.79
https://www.amazon.com/gp/product/B00E0NTPP4/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
XCSOURCE 5PCS IIC I2C Logic Level Converter Bi-Directional Module 5V to 3.3V TE291
$8.99
https://www.amazon.com/gp/product/B0148BLZGE/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
You need either a combination RFID Reader and Keypad, or just an RFID reader:
Lowpricenice Weatherproof 125KHz Wiegand 26 26bit Access Control Keypad RFID Reader Color Black
$17.99
Lowpricenice Weatherproof 125KHz Wiegand 26 26bit Access Control Keypad RFID Reader Color Black
$16.10
https://www.amazon.com/gp/product/B00G4UF7NA/
Note: I believe this link is incorrect.
Nakimo 125khz New RFID Proximity ID Card Token Tags Key Keyfobs (Blue), Pack of 100
$18.39
Elegoo EL-CB-001 UNO R3 Board ATmega328P ATMEGA16U2 with USB Cable for Arduino
$11.86
https://www.amazon.com/Elegoo-EL-CB-001-ATmega328P-ATMEGA16U2-Arduino/dp/B01EWOE0UU/