Arduino Pulse oximeter 2 LEDs red and infrared ,an lcd to display both heart beat and level of oxygen in blood - open to bidding

Could you write a code to measure both heartbeat and oxygen level im using an arduino atmega168 , the concept of the pulse oximeter is to turning the leds on in an alternating way one is a red Led the other is an infrared led that is out base the light these both transmit is picked by a tsl235r light to freq converter the hearbeat is measure by the peaks the oxygen by the intensity. Help please