--- Learning a technology means reclaiming the choices in your own life --- You may have connected an ESP32 development board and sensors before, but the process of developing a jumper-wire experiment into a complete device can feel daunting. There is a great deal of information online about circuit design, PCB fabrication, sensor control, and BLE and Wi-Fi communication. However, connecting this scattered information and completing a board that actually works requires a great deal of trial and error. In this course, you will design and build an ESP32-based sensor board yourself. You will configure the power and firmware download circuits, connect temperature and humidity and light sensors, design a PCB with KiCad, and order it for fabrication. Once the board is complete, you will upload firmware to it and transmit sensor data externally via BLE and Wi-Fi. By the end of the course, you will be able to go beyond simply assembling development boards and sensor modules: you will understand and be able to modify circuits and PCBs to suit your own purposes. The project completed in the course can be reused as a starting point for new projects such as environmental monitoring devices, smart home devices, educational kits, and IoT prototypes. Even in an era when generative AI can rapidly create digital content, physical information such as temperature, humidity, light, and movement in the real world can only be obtained through sensors and hardware. The ability to collect data with a device you built yourself and connect it to a network gives you the power to turn ideas into real-world systems. This course will be helpful for: * Those who have used Arduino or ESP32 development boards but are new to PCB design * Those who want to turn a sensor project made with jumper wires into a single complete board * Those who want to learn KiCad by following an actual ESP32 project * Those who want to build a device that collects sensor data and transmits it via BLE and Wi-Fi * Makers and educators developing environmental monitoring, smart home, or educational hardware * Aspiring entrepreneurs preparing their own IoT products or prototypes * Developers and content creators who want to analyze or process data collected from the real world or use it with AI models Move from being someone who uses development boards to someone who designs their own boards. This course does not merely teach you how to use sensors. It is a course where you experience the entire process of turning an idea into a circuit, turning the circuit into a PCB, and connecting the completed hardware to a network.