I want to build a mailbox alerting mechanism. It will consist of 3 parts.
- Mail drop detection
- Mail retrieval detection
- Wireless communication to our house.
Since this will run of a 9V battery I want power consumption to be as low as possible.
As for wireless communication, I found a module which has a 32uA sleep mode. Since it only needs to communicate when an event occurs, it could be sleeping most of the time.
As for mail retrieval I though of using a nc/no push button, which activates only when the door is opened. This would mean no current is flowing at all as long as the door is closed. I am unsure if this button will fit into the mailbox though, as i may not cut parts out. What other ideas do you have for this?
My biggest problem is the mail drop detection. I was thinking of this flex sensor. Flex Sensor 2.2" - SEN-10264 - SparkFun Electronics
But would this even sense very light mail dropping through the slot in the top of the mailbox? And how long could I expect my battery to work, when this consumes 0.5 watts?
I don't want to use a light sensor as other people might open the drop slot for no reason. The sensor here should actually detect mail being dropped in.
Thanks for your ideas.