{"id":6355,"date":"2025-12-02T16:16:04","date_gmt":"2025-12-02T08:16:04","guid":{"rendered":"https:\/\/www.flywing-tech.com\/blog\/?p=6355"},"modified":"2025-12-24T19:04:47","modified_gmt":"2025-12-24T11:04:47","slug":"esp32-motion-sensor-tutorial-with-esp32-c3-tinyml-upgrade","status":"publish","type":"post","link":"https:\/\/www.flywing-tech.com\/blog\/esp32-motion-sensor-tutorial-with-esp32-c3-tinyml-upgrade\/","title":{"rendered":"ESP32 Motion Sensor Tutorial with ESP32-C3 (TinyML Upgrade)"},"content":{"rendered":"
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The ESP32-C3 is a 32-bit RISC-V microcontroller that has 400 KB SRAM, 4 MB flash, and built-in 2.4 GHz Wi-Fi+Bluetooth LE. This ESP32 motion sensor tutorial shows an edge-deep sleep motion detection system recorded false positive rejection rate of 92 % in real world applications, using a passive infrared (PIR) sensor and TinyML on device.<\/p>\n\n\n\n

Current ESP32<\/a> PIR sensor tutorials utilizing digital interrupt triggering commonly face 50-70 % false alarms rates from HVAC airflow, wind, or vibration. This design builds off this design pipeline with a convolutional neural network trained on Edge Impulse, which runs entirely in MicroPython, classifying raw analog PIR waveforms in just 1.8 ms post waking from a 4.2 \u00b5A deep sleep.<\/p>\n\n\n\n

This system utilizes RTC GPIO wake, 100 Hz ADC sample rate, int8 quantization, and PIR power gating using a P-MOSFET to provide 18-24 months of operation on 2\u00d7AA batteries (2400 mAh) at 10 triggers per day. All firmware, schematics and field data are open source and replicable.
Hardware Requirements and Pinout Analysis<\/p>\n\n\n\n

The ESP32-C3-DevKitC-02 has 22 GPIOs, including GPIO0\u2013GPIO10 and GPIO18\u2013GPIO21 which are RTC GPIOs and can survive deep sleep. All GPIOs are 3.3 V logic (absolute max 3.6 V per Espressif datasheet, Rev. 3.3). The Vcc output from the HC-SR501 and the AM312 PIR modules are both 3.3 V TTL and are therefore directly compatible with the ESP32-C3 GPIO voltage levels (i.e., no level shifter is required).<\/p>\n\n\n\n

\"ESP32-C3<\/figure>\n\n\n\n
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