Nerves support for the RC522 RFID reader.
The RC522 is a cheap RFID module which can be used to read MIFARE-compatible tags at 13.56Mhz.
Combined with a Raspberry Pi, this makes for a pretty compact RFID reader. The RC522 board is so small it easily fits inside most raspberry pi cases.
Currently, only Raspberry PI is supported as the host platform due to the usage of the BCM2835 library in the Port driver.
Furthermore, this library currently only reads the tag UID. The RC522 supports reading and writing MIFARE tag data, but this library does not yet support it.
- Add
nerves_io_rc522to your list of dependencies inmix.exs:
```elixir
def deps do
[{:nerves_io_rc522, "~> 0.1.0"}]
end
```
- Ensure
nerves_io_rc522is started before your application:
```elixir
def application do
[applications: [:nerves_io_rc522]]
end
```
Add the Nerves.IO.RC522 GenServer to your supervision tree:
{Nerves.IO.RC522, {RfidReader.Handler, :tag_scanned}}
When a tag is scanned the function RfidReader.Handler.tag_scanned()
function will now be called with the hex-encoded serial number (UID)
of the scanned tag as its single argument.
Connecting RC522 module to SPI is pretty easy. You can use this neat website for reference.
| Board pin name | Board pin | Physical RPi pin | RPi pin name |
|---|---|---|---|
| SDA | 1 | 24 | GPIO8, CE0 |
| SCK | 2 | 23 | GPIO11, SCKL |
| MOSI | 3 | 19 | GPIO10, MOSI |
| MISO | 4 | 21 | GPIO9, MISO |
| GND | 6 | 6, 9, 20, 25 | Ground |
| RST | 7 | 22 | GPIO25 |
| 3.3V | 8 | 1 | 3V3 |
The Elixir code of this library is distributed under the Apache license.
The files in the src directory contain the rc522 port driver,
which is distributed as GPLv2, as it incorporates the
BCM2835 driver library. See
src/COPYING for the GPL license.