Mailbox notification using Insteon Door Sensor with modified antenna

[tmorse305]

I have been using a Wireless Tag to detect when my mailbox opens for years but it not very reliable in my situation.  My mailbox and the post are aluminum so forget about putting anything inside.  I stuck an accelerometer  based Wireless Tag on the back which sensed vibrations of the box being opened.  It also trips on very windy days, but it worked.

I decided to try using an Insteon door sensor in a water tight box.  I used a hidden door switch that is tripped by a magnet on the mailbox door.  My mailbox is about 120 ft from the nearest dual band device, inside as well so there is a wall in between.  It worked great as long as I was holding onto the water tight box but as soon as I mounted it to the bottom of the mailbox is stopped.  I wondered if straightening out the antenna might improve things.  I copied the antenna length from the Insteon Leak detector.  With the antenna freed from the box it now is rock solid. 

[4481hoods]

Could you possibly supply more detail?

[tmorse305]

On 10/2/2022 at 10:00 AM, 4481hoods said:

Could you possibly supply more detail?

Sure, not sure if there was something specific but here goes:

The pics show how it was installed.  I used the magnet that came with the Insteon door sensor.

The box is:

https://www.amazon.com/dp/B07C97HXX8?ref=ppx_yo2ov_dt_b_product_details&th=1

The hidden door sensor was from my junk box but this is similar:

https://www.amazon.com/QMseller-Recessed-Security-Contacts-Magnetic/dp/B07VQ1DY6T/ref=sr_1_3?crid=1FM4BGBH3E78J&keywords=recessed+security+alarm&qid=1664723050&s=electronics&sprefix=resessed+security+alarm%2Celectronics%2C77&sr=1-3

I unsoldered the original antenna from the PCB then used a piece of insulated 18 AWG wire instead.  Once soldered in I cut it to length using the Insteon leak sensor as my guide.  When I measure the leak sensor I would estimate it is 7.85 cm.

Let me know if  there was something else you were interested in.

 

 

Edited October 3, 2022 by tmorse305
mm>cm

[larryllix]

Did you use a multiple of the wavelength for the length or just wing it?

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[4481hoods]

I used Open/Close sensor in a waterproof box, mounted on a sign post , ran wires to the mailbox, with an alarm  contact and it seems to work quite well.

[dbuss]

2 hours ago, larryllix said:

Did you use a multiple of the wavelength for the length or just wing it?

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On 10/1/2022 at 4:37 PM, tmorse305 said:

I copied the antenna length from the Insteon Leak detector.

 

[tmorse305]

23 hours ago, larryllix said:

Did you use a multiple of the wavelength for the length or just wing it?

I calculated the 1/4 wavelength to be around 8.2cm but then I remembered the leak sensor had a straight antenna so I went with that length which is a bit shorter.

Edited October 3, 2022 by tmorse305
mm>cm

[larryllix]

On 10/3/2022 at 9:58 AM, tmorse305 said:

I calculated the 1/4 wavelength to be around 8.2mm but then I remembered the leak sensor had a straight antenna so I went with that length which is a bit shorter.

Yeah. I never did know how all the bends and folds affects the length and without all the fancy equipment, it mostly a trial and error thing, I guess.

Don't know how to detect an error though.


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Edited October 31, 2022 by larryllix

[KSchex]

@tmorse305  Cool job on your mail box.  Nice and simple.

I Z-Waved my mailbox about 5 years ago.  I used an Aeotec window switch with 2 D batteries.  The D's don't fail as often in the winter weather.  Everything is mounted on an aluminum plate on the rear inside the mailbox.  As you can see I cut out the back of the mailbox and put a plexiglass cover over it.  I did paint the PCB with coating to protect it from the weather.  Been working ever since with out failure.