AP_DHCP

A minimal Wi-Fi Access Point and DHCP server for the Raspberry Pi Pico W, featuring a simple web interface for input and result display.

Overview

AP_DHCP turns your Raspberry Pi Pico W into a standalone Wi-Fi access point with a built-in DHCP server. It also runs a lightweight HTTP server that serves a plain text API for user input and displays computed results. This project is ideal for embedded applications, IoT demonstrations, or educational purposes where a self-contained wireless network and web interface are required.

Features

• Wi-Fi Access Point: Pico W acts as a wireless AP with configurable SSID and password.
• DHCP Server: Assigns IP addresses to clients connecting to the AP.
• Web Server: Serves a plain text API for user input and result retrieval.
• LED Control: Example endpoint to toggle the onboard LED via the web interface.
• C++ Implementation: Uses lwIP, Pico SDK, and CYW43 driver for networking.

Directory Structure

AP_DHCP/
├── CMakeLists.txt
├── main.cpp
├── dhcpserver/
│   ├── dhcpserver.cpp
│   └── dhcpserver.h
├── serverlogic/
│   ├── serverlogic.cpp
│   └── serverlogic.h
└── README.md

Requirements

• Raspberry Pi Pico W
• Pico SDK
• CMake 3.13+
• GCC toolchain for ARM (e.g., arm-none-eabi-gcc)
• lwIP and CYW43 driver (provided by Pico SDK)

Building

1. Clone the repository and initialize submodules if needed.
2. Set up the Pico SDK:

   git clone https://github.com/raspberrypi/pico-sdk.git
   cd pico-sdk
   git submodule update --init

3. Configure and build the project:

   cd /path/to/AP_DHCP
   mkdir build
   cd build
   cmake ..
   make

   The output will be a UF2 file (e.g., AP_DHCP.uf2).

Flashing

1. Hold the BOOTSEL button on your Pico W and connect it via USB.
2. Copy the generated .uf2 file to the mounted drive.

Usage

1. After flashing, the Pico W will start as a Wi-Fi access point (default SSID: picow_test, password: 9998888999).
2. Connect your device to this Wi-Fi network.
3. Use a web browser or HTTP client to access http://192.168.4.1/.
4. To compute a result, send a GET request to the root endpoint with input1 and input2 as query parameters, e.g.:

   http://192.168.4.1/?input1=5&input2=10
   

   The server will respond with the result as plain text.
5. The /ledtest endpoint allows toggling the onboard LED and still serves a minimal HTML page.

Customization

• SSID and Password: Change the ap_name and password variables in main.cpp.
• DHCP Range: Adjust DHCPS_BASE_IP and DHCPS_MAX_IP in dhcpserver.h.
• Web Logic: Modify serverlogic/serverlogic.cpp and the plain text API in main.cpp as needed.

License

This project is licensed under the MIT License. See the source files for details.

Credits

• Based on the MicroPython project's DHCP server implementation.
• Uses Raspberry Pi Pico SDK and CYW43 driver.

Troubleshooting

• Ensure your Pico W is running the latest firmware.
• Check your firewall or network settings if you cannot connect to the AP.
• Use a serial terminal to view debug output if needed.

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