Hello,
I'm would like to replicate a wireless mailbox notifier that's on the Low Power Lab project. Basically, it's an battery-powered Arduino with a wireless module and a hall effect sensor, and when the mail box gets opened, the hall effect sensor senses this and the Arduino sends a signal to a base station.
Some things I would like advice on:
Is there something else that would be better than a hall effect sensor in terms of current consumption? A limit switch might be better, but much more tricky to mount correctly...
What's the best way to handle sleep:
a) Sleep the Arduino for a second, and wake up just long enough to power the hall effect sensor via digital output pin and sense whether mailbox door is opened. Assume mailman keeps the door opened for greater than 1 second.
b) Put the Arduino in deep sleep but power the hall effect sensor all the time. The hall effect sensor wakes up the Arduino.
raschemmel:
How about more information about the mailbox, like a photo or drawing so we know what to suggest ?
Ok, here's the picture of the setup from Low Power Labs. I was actually thinking of putting the Arduino UNDER the mailbox, and the magnet on the underside of the mailbox door. When the mailbox door opens, the underside rotates back and the magnet gets closer to the Arduino sensor.
I think it's a bit illegal to modify USPS mailboxes?...so let's try to keep it inconspicuous.
You could just use the magnet to operate a reed relay which powers the Arduino up when the door is opened. I'm not clear whether you want the Arduino to remain powered up after the door is closed again, but if necessary you could use a transistor controlled by the Arduino to keep it powered up as long as necessary.
