I have followed the tutorial from Makezine about an Infrared heart-beat sensor, and I have essentially used the same components listed on the video (that is, the same resistors and the same IR Emitter and Detector).
So, with a simple source-code just reading the analog output and printing it to the Serial Monitor, I see that the sensor is working fine by just analyzing how the amplitude changes as I move the emitter around the sensor.
The problem begins when I try to put my finger on the sensor (I've tried many different component angles, even 180°), and in my serial monitor, the amplitude is almost constant, that is, it doesn't even make sense comparing to my real heart beat rate. It looks something like (10ms delay):
Now, I want to know if there is a way to amplify the sensibility on this sensor, if possible without using any op-amps, or if I'd have to change the IR components to something stronger, like the ones that look like a usual color LED.
Or even if the ambient light is interfering (which I don't think so, because I cover pretty much the entire IR pair with my fingers), or if the unamplified current has too much resistance (which I also think it doesn't influence in this specific problem, but I may be wrong).
Other than that, any solution is appreciated.