Real-Time Arrhythmia Detection at the Edge: Deploying TinyML on ESP32 for Raw ECG Analysis

In the world of wearable health technology, the holy grail has always been moving intelligence from the cloud to the edge. Waiting for a cloud server to analyze your heart rhythm is not just a latency issue—it's a privacy and battery life concern. Today, we are diving deep into TinyML , Edge AI , and ECG signal processing to build a real-time abnormality detector. By leveraging TensorFlow Lite for Microcontrollers and the versatile ESP32 , we can process raw electrocardiogram (ECG) data locally. This approach ensures low-latency detection of arrhythmias while keeping sensitive medical data on-device. If you've been looking to bridge the gap between high-level deep learning and low-level embedded systems, you're in the right place! The Architecture: From Raw Signal to Insight 🏗️ The pipeline involves capturing a high-frequency analog signal, cleaning it, and feeding it into a quantized Convolutional Neural Network (CNN). Here is how the data flows through our ESP32: graph TD A[Raw ECG Signal/Sensor] -->|ADC Sampling| B(Preprocessing: Bandpass Filter) B --> C{Buffer Management} C -->|Windowed Segment| D[TFLite Micro Inference Engine] D --> E{CNN Model Classification} E -->|Normal| F[Log: Sinus Rhythm] E -->|Abnormal| G[Trigger Alert: Arrhythmia] G -->|Bluetooth/Wi-Fi| H[Mobile Dashboard] Prerequisites 🛠️ To follow this advanced guide, you'll need: Hardware : ESP32 (DevKit V1 or similar). Sensor : AD8232 ECG Module (or simulated ECG data). Software : Arduino IDE or PlatformIO. Frameworks : TensorFlow Lite for Microcontrollers (TFLM), EloquentTinyML (optional wrapper), or the standard C++ TFLM library. Step 1: Model Training & Quantization 🧠 Before we touch the C++ code, we need a model. Typically, we use the MIT-BIH Arrhythmia Database to train a 1D-CNN. The crucial step is Post-Training Quantization . Since the ESP32 doesn't have a dedicated NPU, we convert our 32-bit float model into an 8-bit integer (INT8) model. This reduces the size by 4x and speeds up inference s