--- title: "Building a PoE Network Speaker with the W55RP20" url: "https://maker.wiznet.io/nexp/contest/building-a-poe-network-speaker-with-the-w55rp20/" markdown_url: "https://maker.wiznet.io/nexp/contest/building-a-poe-network-speaker-with-the-w55rp20/md" type: "Contests" author: "nexp" author_url: "https://maker.wiznet.io/nexp/" original_author: "JonghoPark" published: "2026-06-19" language: "en" likes: 3 views: 290 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # Building a PoE Network Speaker with the W55RP20 > A PoE-powered network audio speaker based on W55RP20, using Ethernet for audio streaming and an external DAC for high-quality playback. Original author: JonghoPark ## Documents and links - [W55RP20 Arduino - I2S Arduino AMP TAS5825P WAV File Output Test](https://nexp.tistory.com/4303) (code) - [W55RP20 Arduino - Audio Output Test via Network](https://nexp.tistory.com/4305) (code) - [W55RP20 Arduino - Improving iperf Transmission Rate Using Ethernet3 Library](https://nexp.tistory.com/4308) (code) - [Measuring Maximum UDP Transmission Rate in W55RP20 Pi Pico C/C++ SDK Environment](https://nexp.tistory.com/4309) (code) - [\[W55RP20-4032\] 96kHz High-Quality Audio Transmission Test via UDP (I2S Output)](https://nexp.tistory.com/4311) (code) - [\[W55RP20-4032\] W55RP20 4032 Standard Pin Map Board Form](https://nexp.tistory.com/4294) (schematics) - [Building a PoE-based Network Speaker Using W55RP20](https://nexp.tistory.com/4315) ## Article ## Building a High-Performance PoE Network Speaker with the W55RP20 ![](https://maker.wiznet.io/upload/ckeditor5/617942194%5F1781899511%2Epng) This article shares the development process of a real-time audio streaming network speaker built using the W55RP20 System-in-Package (SiP), which combines the RP2040 microcontroller and the W5500 Ethernet controller into a single chip. The W55RP20 is a cost-effective yet powerful networking solution, making it an excellent choice for PoE (Power over Ethernet)-based network audio devices. This project successfully validates both the hardware and software architecture required to build a PoE-powered network speaker using the W55RP20 and a high-performance audio amplifier. [Embedded media](https://www.youtube.com/embed/Gyevo880WJ8) --- ## 1. Project Overview and Hardware Configuration The W55RP20 provides a powerful networking platform at a very competitive cost. To facilitate rapid integration into real-world applications, a standard pin-compatible development board named **W55RP20-4032** was designed and developed. ### Hardware Specifications - **MCU:** W55RP20 (RP2040 + W5500 + Flash Memory) - **Audio Amplifier:** TAS5825P - Class-D architecture - Hybrid-Pro algorithm for high efficiency and low heat generation - **Interfaces:** - I2S for audio data transmission - I2C for amplifier configuration and control - **Debug & Display:** - Dual NeoPixel (SK6812) LEDs - SSD1306 OLED display for status monitoring ![](https://maker.wiznet.io/upload/ckeditor5/617942194%5F1781898345%2Epng) ![](https://maker.wiznet.io/upload/ckeditor5/617942194%5F1781898386%2Epng) --- ## 2. Development Environment: Arduino vs. Pico C/C++ SDK Initial testing was performed using the Arduino environment with the lwIP networking stack due to its ease of development and rapid prototyping capabilities. However, because lwIP relies on a software TCP/IP stack, network throughput was limited to approximately **2 Mbps**. While this bandwidth was sufficient for CD-quality audio streaming (44.1 kHz, 16-bit), future expansion to high-resolution audio formats (96 kHz, 24-bit and above) required greater network performance. To overcome this limitation, development was migrated to the **Raspberry Pi Pico C/C++ SDK**, enabling direct control of the W5500 hardware TCP/IP stack and significantly improving network efficiency. Later, the Arduino environment was enhanced by integrating and optimizing the **W55RP20_Ethernet3** library, allowing utilization of the hardware TCP/IP offload engine (TOE). As a result: - Arduino + lwIP throughput: ~2 Mbps - Arduino + W55RP20_Ethernet3 throughput: ~6 Mbps - Pico SDK + W5500 Hardware Stack (UDP): ~17 Mbps ### Related Articles - Arduino lwIP Environment - Arduino lwIP UDP Throughput Test - Arduino W55RP20_Ethernet3 UDP Throughput Test - W55RP20 Pico SDK UDP Throughput Test --- ## 3. Technical Challenges and Troubleshooting One of the most significant challenges during development was eliminating audio noise and ensuring stable real-time audio streaming. ### Eliminating Byte-Split Noise Reference: Previously, 32-bit audio samples were transmitted as four separate 8-bit segments. Timing mismatches occasionally caused bit shifts, resulting in audible distortion and waveform corruption. #### Solution Instead of splitting the audio data into individual bytes, complete 32-bit (`int32_t`) samples were transmitted atomically. This ensured that the DAC always received intact audio samples, completely eliminating waveform corruption. ### Improving W55RP20 Ethernet Performance Reference: The Arduino implementation was upgraded to use the W5500 hardware TCP/IP offload engine through the W55RP20_Ethernet3 library. Key improvements included: - Enhanced UDP throughput using iPerf - Optimization specifically for network speaker applications - Successful transmission of 96 kHz high-resolution audio - Verification of audio quality at higher sampling rates ### Solving UDP Transmission Issues on W55RP20 Reference: Since real-time audio applications require low latency, UDP was selected as the primary transport protocol. Key achievements: - UDP throughput optimization - Stable real-time audio streaming - Reliable 96 kHz high-quality audio playback - Reduced packet loss and transmission jitter --- ## 4. Integrated Dashboard and Streaming Features Beyond basic audio playback, a Python-based audio streaming dashboard was developed to provide real-time control and monitoring capabilities. ### Real-Time Audio Streaming Users can select audio sources directly from a PC and stream them instantly to the network speaker. ### Text-to-Speech (TTS) Entered text is automatically converted into WAV audio and broadcast over the network speaker system. ### YouTube Audio Streaming By entering a YouTube URL, the system can extract audio in real time and stream it directly to the speaker. ### Audio Visualization A real-time waveform viewer displays the output WAV signal, allowing users to monitor audio activity visually. ![](https://maker.wiznet.io/upload/ckeditor5/617942194%5F1781898465%2Epng) --- ## 5. Conclusion and Future Development (PoE) This project successfully demonstrated that the W55RP20 provides a stable and high-performance platform for real-time network audio applications. Through extensive hardware and software validation, reliable transmission of high-quality audio over Ethernet was achieved while maintaining low latency and excellent network efficiency. The next phase of development will focus on completing a fully integrated PoE-powered network speaker solution, including: - IEEE 802.3af/at PoE support - Enhanced audio processing features - Multi-speaker synchronization - Network audio broadcasting and paging functions - Commercial-ready hardware design The results confirm that the W55RP20 is a highly capable and cost-effective platform for next-generation network audio and PoE speaker applications. ![](https://maker.wiznet.io/upload/ckeditor5/617942194%5F1781899182%2Epng) ![](https://maker.wiznet.io/upload/ckeditor5/617942194%5F1781898579%2Epng) --- Source: https://maker.wiznet.io/nexp/contest/building-a-poe-network-speaker-with-the-w55rp20/