DIY Doppler Radar Speed Detector

The DIY Doppler Radar Speed Detector operates by leveraging the physical principles of the Doppler effect to measure the velocity of moving objects like vehicles. At the heart of the system is the HB100 Doppler radar sensor, which continuously transmits a high-frequency microwave signal. When this radio frequency wave encounters a moving target, the wave is reflected back to the sensor. Due to the motion of the target, the frequency of the reflected wave shifts slightly relative to the transmitted wave. The HB100 captures this frequency difference and outputs an extremely low-amplitude analog signal known as the Doppler shift frequency. Because this raw signal is typically only a few millivolts, it is routed directly into the LM358 operational amplifier module. The LM358 acts as an active gain stage, boosting the weak voltage fluctuations to a level that can be reliably processed and sampled. Powering the entire instrumentation chain is either a 3.3V battery or a standard 3.3V to 5V DC power supply, connected via a USB Type-C cable. The IndusBoard Coin, driven by its integrated ESP32-S2 microcontroller, processes the conditioned analog data, calculates the corresponding speed, and transmits the telemetry data wirelessly. Finally, all the sensitive electronic components are housed together inside a protective enclosure to ensure reliable field deployment.