# Building a Watt-Meter with ESP-RS and Rocket Backend > [! note]- > The content of this page is generated by audio/video transcription and text transformation from the content and links of this source. Source: [https://fosdem.org/2025/schedule/event/fosdem-2025-5470-building-a-watt-meter-esp-rs-and-a-rocket-backend/](https://fosdem.org/2025/schedule/event/fosdem-2025-5470-building-a-watt-meter-esp-rs-and-a-rocket-backend/) <video src="https://video.fosdem.org/2025/ub2252a/fosdem-2025-5470-building-a-watt-meter-esp-rs-and-a-rocket-backend.av1.webm" controls></video> ## Summary & Highlights: This session at FOSDEM 2025, led by Santiago Saavedra, explores the development of a watt-meter using embedded Rust and a Rocket backend. The project aims to provide a cost-effective solution for monitoring and managing electric vehicle (EV) charging at home, especially in areas with limited electrical capacity. **Project Motivation and Goals** The project was initiated to create a low-cost, efficient watt-meter for EV charging, driven by the need to avoid tripping electrical limits in homes with limited power supply. The speaker sought to learn embedded Rust, emphasizing the importance of managing side-projects with clear objectives and small, incremental steps. **Technical Implementation** The session details the technical aspects of building the watt-meter, including the use of ESP32 microcontrollers and the benefits of Rust's Cargo tool for handling serialization and parallelism. The project also involved developing an API backend using Rocket to manage data and control the EV charging process. **Challenges and Solutions** Challenges included the need for low-cost hardware solutions and the complexity of integrating various technologies. The speaker addressed these by choosing affordable components and leveraging open-source tools to ensure the project remained economically viable. **Future Work and Applications** Future improvements include optimizing the watt-meter with a no-STD Rust version and exploring open-source standards for broader applications. The project highlights the potential for eco-social designers to apply similar methods in developing sustainable technologies. ## Importance for an eco-social transformation The session is crucial for eco-social transformation as it demonstrates how open-source technologies can lead to more sustainable and cost-effective energy solutions. The project addresses the ethical issue of making technology accessible and affordable, especially for communities with limited resources. For eco-social designers, the use of embedded Rust and Rocket backend offers a pathway to develop similar sustainable solutions. Challenges include ensuring the affordability of hardware and overcoming technical barriers in integrating open-source standards. Political support for open-source initiatives and community engagement are also essential for broader adoption. ## Links [Wattmeter code on GitHub](https://github.com/ssaavedra/esp32-amp-sensor) - Source code for the watt-meter project [Backend code on GitHub](https://github.com/ssaavedra/amp-sensor-backend) - Source code for the API backend