Nowadays the wearable devices market is robustly booming, especially in a society where an ever-increasing importance is given to the healthcare. This thesis project is aimed to fill a gap in the current ECG state of art, by implementing a smart wrist device to detect the ECG signal and send it to any other mobile device via Bluetooth Low Energy (BLE) interface. The main challenge is to move almost all the signal processing to the digital domain, in order to reduce the hardware and energy consumption and make the system smaller and easier to manage. The system is composed by a single board circuit, supplied by a USB rechargeable battery, two electrodes (to detect the heart voltage pair from the wrists) and a dedicated application, able to display the received data.