Hi everyone, i am a complete newbie to arduino and am trying to get a signal from a PPG sensor without an op Amp. I have wired the sensor up in the same way as the Arduino Potentiometer sketch but so far have just had a random reading. The ultimate goal is to turn servos with the output data. Any tips or hints would be greatly appreciated. 
A part number or spec would help.
Hi yes, of course, the sensor that i am using is the Cosy (TM) Infra-Red Finger / Ear lobe Clip Sensor EP-107. You can see the spec here http://www.cosycommunications.com/Digitalpulsemonitorcatalogue.htm.
Many thanks.
This:
http://www.cosycommunications.com/earclipsensor.pdf
?
So, what have you got on the output side of the photodiode?
Hi, i used an arduino duemilenova, (i cut off the jack plug the photo-sensor came with) so as to connect the wires directly into the arduino hoping to get a signal read in the serial monitor which so far gave random figures. .
Did you install a pull-up or pull-down resistor? If so, what value?
Hi, thanks for your reply. I was thinking of using a pull-up resistor of 1 Mega ohm. I'm still in the process of assembling. Previously I used no resistor so am hoping this will make a difference to the signal. I was also considering using an opAmp TS358 or LM741CN from Maplin and have yet to experiment with these also.