When you have an ESP but want Router Station(Sta) + Access Point(Ap) in mixed mode with NAT

This project provides two binaries:

1. esp-wifi-ap: Wi-Fi Access Point with client distance measurement using RTT
2. esp-wifi-client: Wi-Fi Station client with RSSI-based distance estimation

• Device Naming: Friendly device names generated from MAC addresses
• Distance Measurement:
  • AP: RTT (Round Trip Time) for precise ranging
  • Client: RSSI-based distance estimation
• Chip Support: ESP32-C6 (default) and ESP32-C3
• Robust Logging: Comprehensive Wi-Fi event and connection status logging
• Static DHCP Reservations: Pin specific client MACs to deterministic IP addresses through .env
• Network Cycling: Client can cycle through multiple Wi-Fi networks with button press
• Auto-reconnection: Automatic reconnection handling when networks become unavailable

• Target: riscv32imac-esp-espidf
• Chip: esp32c6
• Default configuration - no additional flags needed

• Target: riscv32imc-esp-espidf
• Chip: esp32c3
• Feature flag: --features esp32c3
• Architecture: RISC-V 32-bit single-core @ 160 MHz
• Memory: 400 KB SRAM, 384 KB ROM

cp .env.example .env

Install ESP_IDF (google it!) run export.bash or export.fish from ESP_IDF get tag v5.4.1 It has to say sth like:

idf.py --version
ESP-IDF v5.4.1

# Using justfile (recommended)
just build        # Build for ESP32-C6
just flash        # Flash to ESP32-C6
just run          # Build, flash, and monitor

# Or using cargo directly
cargo build --release --target riscv32imac-esp-espidf
espflash flash --monitor --chip esp32c6 target/riscv32imac-esp-espidf/release/esp-wifi-ap

# Using justfile (recommended)
just build-c3     # Build for ESP32-C3
just flash-c3     # Flash to ESP32-C3  
just run-c3       # Build, flash, and monitor ESP32-C3

# Or using cargo directly
MCU=esp32c3 cargo build --release --target riscv32imc-esp-espidf --features esp32c3
espflash flash --monitor --chip esp32c3 target/riscv32imc-esp-espidf/release/esp-wifi-ap

# ESP32-C6 (default)
cargo build --bin esp-wifi-client --release
cargo espflash flash --release --bin esp-wifi-client

# ESP32-C3 
MCU=esp32c3 cargo build --bin esp-wifi-client --release --target riscv32imc-esp-espidf --features esp32c3
espflash flash --monitor --chip esp32c3 target/riscv32imc-esp-espidf/release/esp-wifi-client
# OR using tasks  
cargo run --bin esp-wifi-client

# ESP32-C6 (Default)
just build          # Build for ESP32-C6
just flash          # Flash ESP32-C6
just run            # Build, flash, and monitor ESP32-C6 (AP mode)
just run-client     # Build, flash, and monitor ESP32-C6 (Client mode)

# ESP32-C3 (Feature)  
just build-c3       # Build for ESP32-C3
just flash-c3       # Flash ESP32-C3
just run-c3         # Build, flash, and monitor ESP32-C3 (AP mode)
just run-client-c3  # Build, flash, and monitor ESP32-C3 (Client mode)

# Utility commands
just where_my_esp_at    # Find ESP device ports

Make sure to set up your .env file:

cp .env.example .env
# Edit .env with your Wi-Fi credentials:

# Access Point settings
AP_SSID=rust-was-here
AP_PASS=change-me-for-your-own

# Multiple Wi-Fi networks for client cycling
ST_SSID_1=HomeWifi
ST_PASS_1=homepassword123

ST_SSID_2=WorkWifi
ST_PASS_2=workpassword456

ST_SSID_3=GuestWifi
ST_PASS_3=guestpassword789

# Optional static DHCP reservation (MAC without separators)
# DHCP_AABBCCDDEEFF=192.168.4.50

Static leases follow the format DHCP_<MAC>=<IP>, where the MAC address is 12 hexadecimal characters without separators (colons/dashes). For example, to reserve 192.168.4.50 for device AA:BB:CC:DD:EE:FF, set DHCP_AABBCCDDEEFF=192.168.4.50 in your .env. Use addresses above 192.168.4.100 for these static leases to avoid conflicts with dynamic assignments.

The client supports cycling through multiple Wi-Fi networks:

1. Configure multiple networks in your .env file using the format ST_SSID_X and ST_PASS_X
2. Press GPIO0 button (boot button) to cycle to the next network
3. Automatic wrap-around: After the last network, it cycles back to the first
4. Real-time feedback: Shows which network is currently selected and connection status
5. Auto-reconnection: Attempts to reconnect if connection is lost

• GPIO0 (Boot Button): Cycle to next Wi-Fi network
• Hold button: Immediate network switching (disconnects current, connects to next)

The client uses RSSI (Received Signal Strength Indicator) to estimate distance to the AP:

• Formula: Distance = 10^((RSSI_ref - RSSI) / (10 * n))
• RSSI_ref: -30 dBm (reference at 1 meter)
• Path Loss Exponent (n): 2.0 (free space)
• Distance Ranges:
  • Very Close: <1m
  • Close: 1-5m
  • Medium: 5-15m
  • Far: 15-50m
  • Very Far: >50m

Note: RSSI-based distance is an approximation and can vary significantly based on environment, obstacles, and interference.