Despite the technological development of transmitting mails, conventional mail is still needed.
People occasionally forget to check their mailbox, thus they miss receiving important envelops which are still sent to mailbox, such as the ones containing official documents and bills.
The goal of the present project is building a low power device that notifies its owner regarding incoming mail packages, and counts them.
The project aims to build a small device that fits in a mailbox, it notifies the owner of incoming new mail and number of received packages.
The device has low power consumption so that a battery is enough as a power supply.
The main controller is ESP32 which has two processors, one of them is ultra-low power processor, which functions in deep sleep mode while the main processor is off, to serve the low power consumption of the device.
The event trigger is a microswitch connected to the controller in normally open mode, so it does not consume power in sleep mode, it wakes up the main processor whenever there is a new event, the project’s event is opening the mailbox’s door.
The mail sensor is a weight sensor which detects weight change in the box, it consists of 1kg loadcell which measures the weight according to change in resistance using Wheatstone bridge, in addition to an ADC amplifier which converts the output of the loadcell to a readable output by the controller. The sensor is put to sleep when the ESP32 is in deep sleep mode serving low power consumption.
The communication tool is LoRa SX1278, iot device which does not need internet to communicate, it can send and receive messages within a radius of 15km.
The power unit consists of a charger with LED indicators to inform the owner about charging status and quality of the power supply, a voltage stabilizer to 3.3V, and a 3.7V lithium battery with capacity of 4000mAh.
At the end, the device met the project requirements. It detects incoming mail and sends a message to the owner when a new package arrives. It updates him about number of packages waiting in each message. It also informs him whenever the mail is collected. Using this device, the owner does not have to check for mail periodically, only when he receives a message about new incoming mail.
