Gearing Up for HomeKey-ESP32

Before you embark on your HomeKey-ESP32 journey, let’s make sure you have the necessary tools and hardware. Think of this as gathering your essentials before a grand adventure! Having these prerequisites in place will ensure a smooth and hassle-free experience.

1. Essential Software

1.1. esptool

You have two options for esptool to flash the firmware onto your ESP32:

1.2. Python 3.x (Only if using esptool.py)

• What it is: A versatile programming language.
• Why you need it: If you choose to use the command-line esptool.py, you’ll need a compatible Python installation for it to run correctly on your system.
• How to get it: Python usually comes pre-installed on Linux and macOS. For Windows, or if you need a specific version:
  • Python Downloads

2. Hardware You’ll Need

The required hardware can be obtained either by sourcing all the parts yourself or by using an integrated PCB that has it all on a single board.

2.1. Option A - Sourcing parts yourself

2.1.1. ESP32 Development Board

• What it is: The brain of your HomeKey-ESP32 device! A microcontroller board with Wi-Fi and Bluetooth capabilities.
• Why you need it: This is where our HomeKey magic lives.
• Recommendation: Look for a board with an ESP32-C6, however, other ESP32 development boards should also work fine, precompiled firmware is being released for ESP32, ESP32-S3, ESP32-C3, or ESP32-C6.

ESP32 Buyer’s Guide

Generally, any board should be fine. However, some may have non-genuine modules or just cheap flash chips with low endurance. There is no real way of telling which is the better clone. Genuine modules typically have “ESPRESSIF” etched on the metal casing.

2.1.2. NFC Reader Modules (PN532, PN7161 and ST25R3916)

HomeKey-ESP32 supports PN532, PN7161, and ST25R3916 NFC controllers.

• PN532:

  • Interface: SPI protocol.
  • Recommendation: Ensure you have a PN532 module that supports SPI communication (for red Elechouse boards/clones, DIP switches must be set to 0 and 1).
  • Avoid long jumper wires between the module and ESP32 to maintain signal integrity.

• PN7161:

  • Interface: SPI protocol with dedicated IRQ (Interrupt Request) and VEN (Enable/Reset) control pins.
  • Features: Enhanced Contactless Polling (ECP) support, fast tag discovery, integrated presence checks for non ISO-DEP cards, and reliable hardware performance.
    • PN7161 has native ECP support and that is how ECP is implemented on this firmware for it, however, currently there’s no fallback implemented for PN7160 which doesn’t has native ECP support.

• ST25R3916:

  • Interface: I2C protocol

Choosing Your NFC Module: A Mini Buyer’s Guide

When shopping for a PN532, check boards with blueish components instead of black ones. Those blueish components are Wire-wound RF inductors that provide superior antenna impedance matching, ensuring efficient power transfer to the antenna.

SMD Multilayer RF Inductors

You’ll mostly find boards with these two black components. They do the job, just not as much as you’d want them to, but they are cheap.

Meh

Wire-wound RF inductors

Check for those two blueish components, this is what should be used for impedance matching, which is essential for efficient power transfer to the antenna.

Best

You can also buy from Elechouse for best quality (original red board designer) on their official website.

2.2. Option B - Integrated PCB Boards

• What they are: Custom-designed Printed Circuit Boards. These boards integrate the ESP32 and NFC module, along with other necessary components, into a single, compact solution.
• Why you need them: Using an integrated PCB can significantly simplify wiring, reduce clutter, and result in a more robust and professional-looking final product.
• Where you can find one:
  • @lollokara’s PCB: Features external NFC antenna, RGB LED, and 48V input (alongside USB-C). Available on GitHub or PCBWay.
    • There’s two disconnected pads on the top left to the right of the USB-C that need to be soldered(pad bottom-left SEL1 and pad top-right SEL0) to select SPI mode but a manufacturer like PCBWay can handle this, however, they can sometimes misinterpret, so be prepared to put some solder.
  • CASmo-NFC: Features an integrated NFC Antenna. Manufacturer is located in Germany. Can be ordered from their website.
  • CASmo-NFC-MB-ETH: Features an external NFC antenna, Ethernet port and can powered through USB-C, PoE or 5–24V AC/DC, additionally includes a 5A potential-free relay. Can be ordered from the manufacturer’s website.

2.3. Option C - M5Stack AtomS3 Lite + Unit NFC

The ST25R3916 backend was developed against an M5Stack pairing that needs no soldering, breadboard or jumper wires - the two parts connect with the supplied Grove cable:

Configuration in the web UI:

Measured on this hardware: full FAST-flow authentication in 130-160 ms.