Help with this circuit?

[Lancer]

Hi,

I recently do a direction curtain infrared sensing detector with CC2530 chip. The 2530 establish communication with the host through the Zigbee. The datasheet of CC2530 is here http://www.kynix.com/Detail/756529/CC2530ZDK.html. I hope the infrared sensor is digital which do not need to connect operational amplifier and can directly connect IO port of 2530.

Now the only thing trouble me is that I don't know how to implement the direction recognition function, which means from indoor to outdoor it does not alarm, but it alarms from outdoor to indoor.Does this need to add peripheral control circuit?

I don't know what kind of infrared sensor can I choose? What kind of Fresnel lens should I choose? I hope you can provide the corresponding model and data. It is best to provide the peripheral circuit in which sensors connected to the MCU. I hope you can provide the reference circuit.Thank you very much!

Regards.