This isnt clear to me.
1.) What is this: "pulse oximeter" you have not provided a link to it.. nor the datasheet.
2.) You state you are currently using this device: "ihealth AIR pulse oximeter" to get reads/data... but you have not provided a link to it.. nor a datasheet. How is this getting you a reading? Physical connection? Cloud/wifi/bluetooth connection?
Without you posting some more details.. or at least helping us know what it is you have in front of you.. nobody is going to be able to help you unfortunately.