I am using MAX30102 PPG sensor which consists of IR and RED led and photodiode to detect the PPG wave pattern. It is a reflective sensor.
It seems to be giving the inversed PPG pattern when plotting the data.
What are the reasons for the inversion and how can I reverse to the normal PPG wave pattern?
Dear Kasun,
The inversion of the signal may be accomplished by the analog interface circuit.
such as transimpedance amplifier where the op amp works as a current to voltage converter. This configuration is an inverting op amp connection. To return the correct phase of the signal you need to add an inverter op amp stage before acquiring the signal by the microcontroller.
The other solution is to is to multiply the the acquired signal by -1.
I think the second solution which is a software solution is much easier than the had ware solution.
Best wishes
What other device are you using to acquire the signal (like microcontroller or something like that?) can you count correctly?
I am using an Arduino library to acquire the data to Serial print.
I think I'm plotting the ADC value in the graph
Dear Kasun,
The inversion of the signal may be accomplished by the analog interface circuit.
such as transimpedance amplifier where the op amp works as a current to voltage converter. This configuration is an inverting op amp connection. To return the correct phase of the signal you need to add an inverter op amp stage before acquiring the signal by the microcontroller.
The other solution is to is to multiply the the acquired signal by -1.
I think the second solution which is a software solution is much easier than the had ware solution.
Best wishes
- Badges
- Science topic
- Similar topics
- Methodology
- Sensors