Mailbox notification project

Hi- I'm new to electronics but have some experience with Arduino. I'm looking to build a simple transmitter / receiver to notify me when my mail has arrived. The mailbox is about 2000 feet away from my house, with other houses blocking the line of sight. The mailbox is one in a bank of boxes, serving my entire street.

My initial idea was to use a photo-resistor, since the box sits dark most of the time and light floods in when the mailbox panel is opened. Ideally, not much power would be drawn while the mailbox is dark. Since I don't want to freak out the mail carrier, I was thinking of putting the whole thing in a padded envelope addressed to me that I could just place in the box on the days I want to be notified.

I've Googled some transmitter / receiver pairs for the Arduino and the HC-12 seems like a possibility, although it has more capability than I need, since I don't need to do serial communication. Also, I'm not sure if its range is quite enough, and it uses 5 volts.

There's one on Sparkfun (RFM22B) that lists its range as 600 meters but I'm wondering if that will be quite enough.

As you can probably tell, I'm inexperienced so any guidance insofar as what to get and how to set it up would be greatly appreciated.

Thanks, John

John0544:
Since I don’t want to freak out the mail carrier, I was thinking of putting the whole thing in a padded envelope addressed to me that I could just place in the box on the days I want to be notified.

A far better choice is to just let the mail carrier know what you are doing.

I agree, but we have different ones all the time. Maybe the solution is to put a note on the padded envelope.

I built such a thing using an LDR to detect light and a 433MHz rf link to trigger a timestamped message on a receiver with a 1602 LCD and RTC. I just made a black false wall at the back of the mailbox so it'd be essentially invisible to anyone looking into the mailbox. Had the antenna hanging out the bottom of the mailbox.

I don't know if you can get transmission considering your distance and obstacles and from inside a metal box a it is. If it's one of those apartment type mailboxes, I'm guessing you don't have the luxury of making an external antenna to the actual box so it's going to be tough.

Thanks INTP. There's a possibility that I can dangle a wire out of the back. I'll check it out.

I just found out that the distance is more like 600 feet.

If someone could recommend a transmitter / receiver pair, I could probably figure out the rest.

Thanks again.

600 feet is a lot different than 2000 feet. How are you even estimating this distance?

A football (American) field, without endzones, is 300 feet long.

Are you saying you live two football fields away from your mailbox?

Sorry about the bad estimate. What I did was, I drove down my street looking at the odometer and the distance was a little over .1 miles.

Is your part of the World covered by Google maps ?

That has a measurement function.

Good tip, thanks SRNET.