Raj previously designed the Easy Pulse heart rate sensor. Now he informs us of an update: “I would like to inform you about the release of a new version of Easy Pulse sensor. The Easy Pulse sensor is designed for hobby and educational applications to illustrate the principle of photoplethysmography (PPG) as a non-invasive optical technique for detecting cardio-vascular pulse wave from a fingertip. It uses an infrared light source to illuminate the finger on one side, and a photodetector placed on the other side measures the small variations in the transmitted light intensity. The variations in the photodetector signal are related to changes in blood volume inside the tissue. The signal is filtered and amplified to obtain a nice and clean PPG waveform, which is synchronous with the heart beat.”
The major components are an MCP6004 Op-amp and HRM-2511E transmission PPG sensor.
The schematic and details can be found at EmbeddedLab.
Via the contact form.
Does anyone know what type of IR LEDs does these sensors use?
If you mean the wavelength then this project uses HRM-2511E sensor that has a 940 nm IR LED. You can build a PPG sensor with regular two-pin IR LED and photodiodes.