Heart rate monitor

Have built the heart rate monitor by Keith Wilson albeit using an infrared led and an ifrared transistor for the sensor and im not getting any meaningfull output. The output from pin 7 of the LM358 is a constant 4volts.
Any ideas as to how i can make this circuit work.
Thank you

Why not try using the visible LED as the design does?.

Had wanted to utilise the absorbtion of infrared light by intravenous blood.
I will try the visible light LED as you suggest and will notify of the changes.
thank you.

Keith Wilson circuit

I realize it was sometime ago that this circuit was looked at, but I am looking into this circuit for a senior design project. I also am having problems getting anything on the output, as there is just a constant voltage. I tried to place a POT and adjust that as well to see if I could get any vary in the output. Didn't if you or anyone has found the issue or solution to my problem. Please let me know.

Thanks