The solution to your problem has likely already been built. It's the remote motion detector. You can buy these on ebay for around 20 dollars US. Just drop the motion detector in the mailbox and it triggers a really loud alarm on the receiving unit inside your house. I have used these in my back garden to detect sneaky racoons digging up my lawn. They claim a very long range, 400ft to 900ft, but I'm not sure how far it would be enclosed in a mail box.
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Wednesday, December 29th, 2021 at 1:21 AM, Robin <mixent...@aussiebroadband.com.au> wrote: > Hi, > > I'm looking for an elegant, simple, cheap means of transmitting a single bit > of information over a distance of 50 > > meters, without wires. > > Imaginative solutions sought. :) > > Regards, > > Robin van Spaandonk mixent...@aussiebroadband.com.au
