I live very rural and my driveway is half a mile long. Installed an automatic gate controller last year and it works great with remote controls in our vehicles and a keypad for regular visitors/family. It is powered by a 30 watt solar panel, 8 amp solar charge controller and 100 amp/hour battery. My issue is that the most powerful remote gate opener I have found will only go about 800 feet (far short of 1/2 mile).
My temporary solution to this situation is to use two old EFJohnson SCADA radios, one at the house and one at the gate. I use a doorbell button to key the radio at the house which turns on the Carrier Detect signal on the radio at the front gate. The radio at the front gate is also powered by the alternative energy solution that powers the gate and receives only(doesn't consume much power). The carrier detect signal drives a relay that provides a contact closure that tells the gate controller to open the gate. One problem with this arrangement is that the gate could easily be opened by someone with a radio keying at the receive frequency of the radio at the gate.
I have recently obtained two 2.4GHz Ethernet radios that I plan to use so that I can have a camera at the front gate that will give me motion sensing abilities and send alerts via text and email when someone comes to our front gate. Using this Ethernet connectivity, I'd like to use two Arduino boards, one at the house with a momentary switch and one at the gate to drive the aforementioned relay.
This will be my first Arduino project and I welcome any and all suggestions and recommendations from those with more Arduino experience than me. I also have plans to make a controller for the Chicken Coop that closes the chicken entrance at dusk and opens it again at dawn, liberating me from the chore of closing chickens in the evening.