When your mailbox lid opens, light floods in. The BoxBinAlert™ Mailbox Sensor detects that flash in milliseconds and fires an alert to your phone — before the carrier even closes the lid.
A mailbox interior is dark — until the lid opens. That flash of daylight is the most reliable, falsest-proof trigger possible. The photo sensor detects it in milliseconds.
The postal carrier opens your mailbox. Natural or ambient light immediately floods the interior — going from near-zero to full brightness in milliseconds.
The photo sensor — mounted 3 inches up on the inside vertical wall, pointing toward the lid — detects the light threshold crossing instantly. No mechanical parts. No moving contacts.
The TX unit (mounted outside) receives the signal from the sensor wire that passes through the ½" hole in the mailbox bottom. It broadcasts a LoRa radio signal up to 2 miles.
Your RX Receiver inside the home catches the signal and sends your email alert — all within 10 seconds of the lid opening. The carrier may still be at your box.
You need a drill, a ½" bit, and a 3M adhesive pad. That's it.
Drill a ½" hole in the bottom of your mailbox. This is where the thin sensor wire passes through from the inside of the box to the TX unit mounted outside on the post.
Thread the short sensor cable through the hole from outside to inside. The photo sensor module sits inside the mailbox; the TX unit and battery stay outside, protected under the box or on the post.
Use the included 3M adhesive pad to stick the photo sensor to the inside vertical wall of the mailbox — approximately 3 inches up from the bottom. Point the sensor lens upward toward the lid. This ensures it catches light the moment the lid cracks open.
Attach the TX unit to the underside of the mailbox or on the mailbox post using the included hardware. The TX unit is weatherproof and stays outside permanently. Run the antenna vertically for best range.
Place the RX Receiver inside your home near a window. Connect it to your WiFi using any phone browser — takes 2 minutes. Enter your email address. Done.
Open your mailbox lid — you should receive a test email within 10 seconds. Close it up. The system runs itself from this point forward. Battery, alerts, everything is automatic.
A mailbox interior is pitch dark when closed. Light only enters when the lid opens — meaning this sensor only fires when mail actually arrives. Wind, vibration, trucks driving by — none of it triggers a false alert.
Photo sensors react in milliseconds — far faster than mechanical tilt switches. The alert is firing before the carrier finishes sliding mail into your box.
Unlike tilt sensors with mechanical contacts, the photo sensor is purely electronic. Nothing to wear out, nothing to corrode, nothing to loosen over time. Built to last years of daily triggers.
Standard rural T2 mailboxes, pedestal boxes, cluster mailboxes, decorative aluminum — if light enters when the lid opens, the photo sensor works. No mailbox modifications beyond a ½" hole.
The photo sensor only consumes meaningful power when light is detected. In a residential mailbox checked once daily, battery life reaches 12–24 months on a single 3.7V rechargeable charge.
The TX unit mounted outside is weatherproof. Operates from -20°F to 140°F. Snow, rain, full Florida summer heat — the system keeps alerting without missing a delivery.
Both sensors use the same TX/RX system and deliver the same free email alerts. The difference is in how they detect — and where they work best.
The Mailbox Photo Sensor ships ready to install. Free email alerts. No subscription. Ever.
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