- on Home & Garden
- Published in issue 7/2009 on page 107
Snail Mail Detector
Since his letter-box is outdoors and quite some way from the house, the author was looking for a simple means of knowing if the postman had been without having to go outside. Circuits for this kind of 'remote detection' come up regularly, but always involve running cables between the letter-box and the detection circuit in the house. This article describes a clever alternative.