“Receive an e-mail when your good ol’ mailbox is opened? No problem with this low-power IoT mailbox guard, using the cheap ESP-01S module!
From now on I will receive an email when the flap of my mailbox has been opened. For this I use the inexpensive ESP-01S module, which can dial into the WLAN and send e-mails. The battery-operated module is simply stuck in the appropriate position in the mailbox.”