First design project

Oct 01, 2006 26 Replies

Yep, you have a sorta RTC built into the system, so it only tests during the daytime. You test for dark, pulse the LED and test for light in case the door is open. You can even use a pulsed LED so you can AC couple the opto sensor to negate background lighting...

Of course, tampering with an official US postal box could probably land you in jail, nowadays... 8-)

Charlie

[snip]

Exactly. That's why I'm trying to figure out a "non-invasive" scheme... perhaps a metal detector to determine that the "loading" side door has opened. I don't think they can do anything to me for putting electronics in the trees ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

formatting link
| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Hello Charlie,

Of course, you have to stay legal there. If it's a box that the home owners association or some other entity put up you can't do anything to it. Also, it needs to be played safe. For example no power connection whatsoever. As to "official" one would have to check the regulations. In our area some people built their own "custom" boxes. Many of those are really pretty.

Regards, Joerg http://www.analogconsultants.com

In article , Charlie Edmondson wrote: [...]

A photocell or photo transistor would serve this purpose nicely.

-- kensmith@rahul.net forging knowledge

A little known part of the Mordern Forestry Act makes it against the law to install, or allow to be installed, any inductive loop into any pinion pine tree.

How about a couple of magnetoresistive devices. Once can be placed nearish to the boxes and the other at some small distance away. A car zipping past on the road would make a signal in both but opening the box would only effect one.

If they use those little Jeeps, you could detect it stopping in front of the boxes.

-- kensmith@rahul.net forging knowledge

At your age, you should walk out there once or twice a day anyway, just for your health. :-)

Good Luck! Rich

...

consider the properties of "actual physical mail"

what comes to my mind is that it has mass and is opaque.

I'd go with a microswitch with a long lightweight lever on it, or some sort of optical setup.

I know of no way to tell good mail from junk, let-alone bills from payments if you can arrange such you may be able to patent it and retire:)

Bye. Jasen

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required