Megadoor
Creator: |
Contents
[hide]Overview
"I don't even know how this happened." - ctag
We're making yet another door auth system. This one will use microcontrollers and NFC.
Hardware
=== V2.0
Coming soon.
Features:
- Single/cleaner breadboard circuit
- 32KB external EEPROM for user credentials
- Lasercut wall mount
V1.0
Hacked together by hfuller and ctag during a two-day sprint. Reads the NFC antenna on the front door and unlocks when a valid card is present. USB authentication is patched through from the original Pi for now.
ATmega DIP Pin | Arduino Pin | Function/Connection |
---|---|---|
15 | D9 | Door Unlock Transistor |
28 | A5 | NFC -> SCL |
27 | A4 | NFC -> SDA |
12 | D6 | NFC -> IRQ |
11 | D5 | NFC -> RST |
Software
Oh boy.
NFC
USB
SIAM32 USB HC
A fascinating student project to implement USB Host Control for Atmega32 systems.
With some help from friends on IRC, the code compiles, but is in somewhat bad shape, and only targets atmega32 and not atmega328p which is what we have.
USB Host Shield
We could buy a USB Shield. It feels like cheating, but is also the most feasible option right now. Also kinda pricey.
https://github.com/felis/USB_Host_Shield_2.0
https://www.circuitsathome.com/products-page/arduino-shields
USB Host Library
We could try one of the USB software libraries for the ATmega328 line of controllers. These all seem to target the chip as the downstream device, rather than the Host Controller.
https://www.obdev.at/products/vusb/index.html
http://www.fourwalledcubicle.com/LUFA.php
https://dicks.home.xs4all.nl/avr/usbtiny/
AT90USBKEY2
We could buy a board specifically designed for USB Host development. Compatible with the LUFA library listed above. This could either replace the atmega328p, or work ancillary to it.