Remote Mail Notifier (and GPS tracker)
A notifier for when mail is received in your mail box! Uses an A9G GPRS/GPS module to send HTTP requests to a web server via the mobile network.
A PHP script then sends messages to a Telegram group chat using the bot API. Since the A9G also has a built-in GPS receiver the mail notifier can be used as a GPS tracker!
Also incorporates a BME280 environmental sensor and should last for around 4-5 years on a single charge of a 10440 lithium battery (~320mAh, equivalent AAA size), if mail is received 3 times per week.