ARDUINO INTERFACING

Hey ppl ,I am entirely new to arduino and i have to work on a group project as a part of my course.i have to design a beacon in which I should use a motion sensor to detect if a person passes throught it and use a wireless module(SparkFun RF Transceiver Breakout - RFM22B-S2 (434 MHz) - WRL-10154 - SparkFun Electronics) to transmit that a person is in a particular room.the receiver is placed in a knee band which a person is wearing.Literally if a person passes through the sensor it should sense and transmit it to the receiver that the person is in a particular room. I know to write the code for motion sensor but i need help in writing the code and interfacing the wireless module. Similarly I have a 5v arduino pro mini but my wireless module is 3.3V and motion sensor is 5V .So my friend told me to use a level shifter.I want to know whether that can be done too.PLs help me ppl.Thanks in advance

You need to break your project down into small pieces and learn each piece separately before you try to combine them.

I suspect SparkFun has some demo code to get you started with transmitting and receiving.
I suspect they also have info about interfacing their 3.3v device with a 5v Arduino.

One of us has to take time to study their website. Which of us should do that, do you think?

If you have a program that does not seem to work post it and we will try to help.

...R