Thinking outside the metal (steel) mailbox

I have a cast aluminum mailbox. I attached the motion senor on the back wall well above the halfway point between the top and bottom. The mailbox is over 75 feet from an indoor Wyze camera. It has not failed to detect the mailbox door opening since it was installed some 2 months ago.

I have this same issue with a fully enclosed metal mailbox that has been broken into a few times, so I really wanted to use a contact sensor to trigger video capture etc. A few additional comments from an electrical engineer with lots of consumer electronics and radio frequency design experience:

  • The fact that you are still seeing 2 bars (a very coarse metric) with this mod is surprising, because the circuit should be tuned to match the antenna impedance, which includes the signal run from the transmitter on the circuit board to the start of the antenna itself. You’ve introduced a huge change to that path, and it’s surprising this still works but reflects well on the Wyze hardware design and wireless protocol choice that it can still work. Bravo to both of you.
  • I would fully expect this arrangement to make the transmission less efficient and to decrease your battery life, just FYI
  • My solution was to leave the contact sensor inside but move it to the hinge end of the box so that the transition from open to closed happens with less linear speed, giving the sensor just enough time to send the “i’m closed” signal before no more RF can get out of the metal box. You’ll notice the signal is tripped before the parts are 100% overlapped, perhaps when they are within 2cm of each other. So if you close the box at a normal speed, this works.
  • With this setup I always get a notification when the box is opened even though the receiving bridge in the back of the camera is 20’ directly behind the mailbox (opposite of line of sight). There is no need to make the antenna be line of sight on the back of the mailbox. The RF signal will go around the mailbox easily once the sensor is outside the metal enclosure.

A few photos of how I arranged this:

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For your information a foamed PVC plastic was used for the
contact sensor enclosure because it would take wood screws better than the
solid PVC. PCV type for the magnet holder didn’t matter in my case because thru
hole machine screws were used.

Good luck with your project.

Victor Maletic

My
thoughts exactly concerning reduced battery life resulting from significantly
altering electronic behavior. Your placement of the contact sensor unit near
the pivot point of the mailbox door to provide sufficient time for the
“I’m closed” signal to escape is ingenious.

My calendar has been
marked when the extended antenna unit went operational. If battery consumption
becomes an issue, I will be implementing your approach.

Thankyou.

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The maximum range with the contact sensor being opened and
closed with my hands at 50’ intervals was about 300’. I stopped there but was
getting 2 bars of signal on the WYZE app. With the antenna extended unit
installed in the mailbox and the mailbox carried under my arm, I found the
range to be about 100’ with 2 bars of signal. Further out, no “Open”
or “Closed” response. All testing was direct line of sight. No
intermediate obstacles.

My nephew is home and he said all of your comments are true. And the antenna extension is working - for now?

Should the extended antenna consume too many batteries or quit working, I plan to try danny.benjamin’s approach. No modification - just smart placement.

Thank you for your comments.

Like Loki, I opted for the motion sensor mounted on the back of the mailbox for my mother and it works great.

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I’m curious, what is your mother’s mailbox made of?

It’s one of those large community mailboxes (condo) made of steel. Her mailbox is #2 in the picture.

I 3D printed some cases for mine and stuck them on The outside with command strips. My camera is further away then 35 ft and it works great.

Also designed an attachment for my gate sensors by mashing up a couple of designs.

I would like to see some pictures.

Here’s the original gate sensor:

Here’s my remix:

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Nicely done nicely implemented, I like both.
Thank you.

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I’m in the same type of situation as itinerans
Mom.
I thought about this idea but then was wondering isn’t there some type of law that doesn’t allow us to mess with mailboxes (the type similar to itinerans) ?
I could be totally trippin about this…so plz excuse me if so lol

Btw - y’all have some of the most unique, awesome ideas, Love it! :grin::grin:

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@GuidoLoko

The U.S. Postal Service would like to warn people that only authorized U.S. Postal Service delivery personnel are allowed to place items in a mailbox. By law, a mailbox is intended only for receipt of postage-paid U.S. Mail.

USPS Mailbox Rules

Frankly the thought that installing a mailbox-has-been-opened
sensor would be illegal never crossed my mind.

So, I looked online for information about mailbox sensors and
found many out there. From DIY’s to major companies selling mailbox applicable
sensor systems.

Furthermore the “USPS Mailbox Rules” given in GuildoLoko’s
comment seem to restrict the what can be placed in a mailbox on an ongoing
basis. It doesn’t address the installation of mail notification systems.

Upon checking out the USPS website, I was not able to find
any news concerning prohibition of mail delivery alert systems attached to mailboxes.
I did see that the USPS was proud of all
the high-tech they have in place for delivering the mail.

My mailman came to deliver my mail as I was completing the
mailbox-door-open system. His concern was that it not-interfere with placing
mail.

So, should I slap a US postage stamp
(cancelled/not-cancelled) on my mailbox sensor device?

I think not!

Yet they still managed to ship a camera FROM Seattle to Memphis (for a weekend) then back to Seattle, before shipping it on to me (just south of Memphis).

I’m wondering how does the battery hold up when placed in or around the mailbox? Can get mighty hot during the summer months, at least where I live.

Probably not well airangle. I think my silvery grey mailbox under a the shade of a large tree will prevent too much heat buildup. So far still seems fine.

Thanks, yep my worry as am in Tucson AZ, and our community boxes are not shaded. Upside I suppose is my house is across from the boxes so perhaps when I get my cam set up ( or a sensor, not sure what all I’ll use the kit contents for) the mail truck alone will send out a motion alert.