This one will be very basic to most people who have done this, but it would have been helpful to me when I started with this stuff, so I’m putting it here.
First, a little background:
In the past couple months I’ve been messing around with the nRF24L01 (just gonna call them nRF’s from now on) radio frequency (RF) modules. Arduino hobbyists love them because they’re cheap (it seems like their competitor in this arena were Zigbee chips, which people seem to say are good but very expensive) and relatively versatile and powerful. They operate in the 2.4GHz frequency range and can actually get a pretty hefty amount of range! My roommate and I did a “range test” where I took one nRF that was just spraying out a constant stream of data, and he took another nRF with an LCD attached that displayed the received data. We went to a nearby park, and literally couldn’t get far enough away from each other to make the data stop being collected, which was about 1000′ according to Google Maps. They’re a lot of fun and really open up some project possibilities, which I’ll put here as I do them.