Question

I have a cheap ECG/HRV/heart rate sensor module for Arduino, bought from Aliexpress. It has 3 electrodes: RA, LA, RL, which I guess mean right arm, left arm, right leg. The module outputs one single time series data, like one referenced electrode of an EEG.

I would like to use this cheap module to record blinks (one coarse channel is enough for this), with its electrodes placed around one eye. But I am stuck with this problem:

What I have found so far on the internet about EOG electrode placement says that the ground electrode should be placed somewhere on the forehead or near the ear/neck. But which of these 3 electrodes should be deemed as ground? What arrangement of the 3 electrodes would you advise? (What are the equivalents of these 3 electrodes in a commercial EOG sensor?)

Answer 1

In order to record blinks using an ECG/HRV/heart rate sensor module, the ground electrode should be placed on the forehead or near the ear/neck. In the case of a module with three electrodes (RA, LA, RL), the RL electrode can be deemed as the ground electrode and placed on the forehead or near the ear/neck.

Step-by-step explanation:

When using an ECG/HRV/heart rate sensor module for recording blinks, the ground electrode should be placed on the forehead or near the ear/neck, as per the placement recommendations for EOG (Electrooculography) electrodes. In the case of your cheap module with three electrodes (RA, LA, RL), you can deem the RL electrode as the ground electrode and place it on the forehead or near the ear/neck. This arrangement will allow you to record blinks using one coarse channel with the electrodes placed around one eye. The equivalents to these three electrodes in a commercial EOG sensor would depend on the specific brand and model of the sensor.