Most exercise/fitness monitions today use optical means to detect the user's heart rate - a technique known as photoplethysmography (PPG). This is convenient and economical, but not terribly accurate.
The Client had developed a hardware platform using electrocardiography (ECG) - ie, sensing the electrical signals from the heart's activity - for greater accuracy of the heart rate measurement.
A 3D accelerometer for motion sensing, and Bluetooth Low Energy (BLE)radio for communication with a mobile app, were also included.
Our first task was to get the
Nordic Semiconductor
nRF8001 BLE radio working. Nordic provide an
SDK in the form of an Arduino Library, so this had to be ported to "conventional" embedded 'C'. |