Computers & Electronics

Wifi contact sensor

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  • Jul 7th, 2020 6:41 pm
[OP]
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Sep 28, 2002
193 posts
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Wifi contact sensor

Hi folks,
I need some advice on a gadget...
I have a sump pit in my house that fills up and gets emptied by a sump pump. But sump pumps often fail, and I need some reassurance when they do.
I want to have a sensor on the pit when the level of water gets to a certain point.
I know there are products on the market that do that. However, the pit already has a little floatie sensor, which is wired to a legacy alarm sensor that no longer is use. The floatie does trigger the sensor (it lights up but has nowhere to send the signal as the alarm system is uninstalled). It’s wired to that sensor through simple two contacts. Kind like on (when connected) and off (when disconnected).
So, I’m looking for an updated sensor that will send an alert when the floatie is triggered (contacts are connected). Should be wifi capable, as I’d like to get a text or an email when triggered.

What products should I be looking for? Any recommendations?
Thanks!
To alcohol - the cause of and solution to all of life's problems.
15 replies
Deal Fanatic
Jan 21, 2018
7563 posts
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Vancouver
Lots of companies sell cheap door/window sensors for smart home security, mostly using non-contact magnetic proximity switches. They usually trigger when the two parts are an inch or two apart - it would be easy enough to adjust placement to trigger at the right point on any moving part like a float.

The catch is that they don't use WiFi, they use Zigbee or Z-Wave, so you also need a hub supporting those communication protocols. WiFi is a power-hungry protocol intended to support continuous connection and high-speed communication, so it would drain batteries too fast for small standalone devices like these senors. The low-power only-on-demand protocols allow them to run on small button batteries for a year.
[OP]
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Sep 28, 2002
193 posts
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Scote64 wrote: Lots of companies sell cheap door/window sensors for smart home security, mostly using non-contact magnetic proximity switches. They usually trigger when the two parts are an inch or two apart - it would be easy enough to adjust placement to trigger at the right point on any moving part like a float.

The catch is that they don't use WiFi, they use Zigbee or Z-Wave, so you also need a hub supporting those communication protocols. WiFi is a power-hungry protocol intended to support continuous connection and high-speed communication, so it would drain batteries too fast for small standalone devices like these senors. The low-power only-on-demand protocols allow them to run on small button batteries for a year.
I think the magnetic moving parts wouldn’t be ideal, as I am not sure how they would react to water. I’d prefer to avoid putting in a different mechanical structure, as the existing floatie works well to send the signal. It’s just the electronic part that receives the floatie connection and sends an alarm that I’m looking for.

A hub might be a compromise if Wifi isn’t an option.
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Deal Fanatic
Jan 21, 2018
7563 posts
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Vancouver
dufFWant wrote: I think the magnetic moving parts wouldn’t be ideal, as I am not sure how they would react to water. I’d prefer to avoid putting in a different mechanical structure, as the existing floatie works well to send the signal. It’s just the electronic part that receives the floatie connection and sends an alarm that I’m looking for.

A hub might be a compromise if Wifi isn’t an option.
As long as you keep the electronic module out of the water, the other part contains just a simple magnet. In fact any magnet will do to trigger the switch.

But I understand what you're looking for. If I were doing it, I would use the same cheap door/window contact sensor, but crack open the electronics module and look for the magnetic reed switch (the switch that actually opens and closes with a magnetic field nearby). It's usually easy to recognize - they are often transparent so you can actually see the switch contacts operate inside the glass envelope as you move a magnet closer and further away. Solder 2 wires to the reed switch contacts and hook them up to your float sensor contacts so that the float acts as the on/off switch.
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Mar 2, 2014
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I don't have a sump pump but I do use this product in my laundry room - https://www.homedepot.ca/product/baseme ... 1000800787
It has been triggered once too when the water overflowed from laundry sink onto floor.
EDIT: The sensor on this can actually come out of the unit to be placed on the floor, to keep the unit itself free of water

However when i search for watchdog on homedepot, I see full suite of sump pump products with battery backup and wifi module
https://www.homedepot.ca/search?q=watchdog#!q=watchdog
Deal Addict
Nov 23, 2004
1117 posts
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Ontario
How tech savvy are you? You could use something like a Wemos D1 WiFi IOT board to interface with the existing sensor (I'm guessing the floatie is just a switch in it's most basic form anyway). I use these boards to build and interface with sensors all over the house - doorbell sensing, temperature, humidity, motion, door open/close, etc. I connect mine back to Home Assistant, but you could just as easily have it trigger an email or push notification directly without a home automation platform in the middle.

That being said, it'll require a little bit of tech savviness, or a willingness to do some google searching to find something similar to what you want and start some discussions with others on how to adapt to your needs. The boards are $3, plus your grunt work to make it do what's needed ;)
[OP]
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Sep 28, 2002
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scorown wrote: I don't have a sump pump but I do use this product in my laundry room - https://www.homedepot.ca/product/baseme ... 1000800787
It has been triggered once too when the water overflowed from laundry sink onto floor.
EDIT: The sensor on this can actually come out of the unit to be placed on the floor, to keep the unit itself free of water

However when i search for watchdog on homedepot, I see full suite of sump pump products with battery backup and wifi module
https://www.homedepot.ca/search?q=watchdog#!q=watchdog
This product seems to produce only a physical alarm, which won't work, as need it to alert me on my phone (when not home).

I wonder if something like this would be a good solution:

https://www.homedepot.ca/product/globe- ... 1001544411
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[OP]
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Sep 28, 2002
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mindabsence wrote: How tech savvy are you? You could use something like a Wemos D1 WiFi IOT board to interface with the existing sensor (I'm guessing the floatie is just a switch in it's most basic form anyway). I use these boards to build and interface with sensors all over the house - doorbell sensing, temperature, humidity, motion, door open/close, etc. I connect mine back to Home Assistant, but you could just as easily have it trigger an email or push notification directly without a home automation platform in the middle.

That being said, it'll require a little bit of tech savviness, or a willingness to do some google searching to find something similar to what you want and start some discussions with others on how to adapt to your needs. The boards are $3, plus your grunt work to make it do what's needed ;)
I don't think I have the patience nor the know-how for this level of tinkering. But seems to be a great product with infinite possibilities if one is up for it. Good to know it exists!
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Member
Nov 18, 2019
329 posts
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GTA
If the trigger is a simple yes or no, it can be translated as if a circuit is connected or not. Is it possible to set that up on a Raspberry Pi board? Those come with WIFI already, and I believe you can power it through a USB port.

I just googled: https://www.raspberrypi.org/forums/view ... p?t=239329

Good Luck
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Mar 2, 2014
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dufFWant wrote: This product seems to produce only a physical alarm, which won't work, as need it to alert me on my phone (when not home).

I wonder if something like this would be a good solution:

https://www.homedepot.ca/product/globe- ... 1001544411
It would work but as others pointed out, wifi is power hungry so expect frequent battery changes. Your best bet for wifi based is a wired wifi sensor. Homedepot does have a "basement watchdog" branded wifi monitor that's wired but I think it needs their full system
Deal Addict
Nov 23, 2004
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ChibaK wrote: If the trigger is a simple yes or no, it can be translated as if a circuit is connected or not. Is it possible to set that up on a Raspberry Pi board? Those come with WIFI already, and I believe you can power it through a USB port.

I just googled: https://www.raspberrypi.org/forums/view ... p?t=239329

Good Luck
RPI would be overkill :) If you're into this stuff, check out ESP8266 boards like the Wemos D1 I mentioned above. They're about <$3 a board, have a bunch of IO, and use the really simple Arduino programming language (or if you want even easier, they can be re-flashed with the likes of ESP Home or Tasmota firmware to make development into an even more natural language). They also support deep sleep methods, which makes it possible to battery power sensors and get 1+ years from a battery depending on polling times.
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I think these methods are way beyond my ability :)
I think I’m going to stick with the commercially available solutions like the one I linked above. It says in the Globe Electric site that the battery (CR2) is good for five years. Is that realistic?
https://globe-electric.com/en/product/g ... ite-50027/
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[OP]
Jr. Member
User avatar
Sep 28, 2002
193 posts
38 upvotes
scorown wrote: It would work but as others pointed out, wifi is power hungry so expect frequent battery changes. Your best bet for wifi based is a wired wifi sensor. Homedepot does have a "basement watchdog" branded wifi monitor that's wired but I think it needs their full system
Yes, the wifi version of Watchdog is more suited for sump pump back up battery monitoring. I have a back up generator, so that shouldn’t be an issue. Thanks for the research, though!
To alcohol - the cause of and solution to all of life's problems.
Deal Fanatic
Jan 21, 2018
7563 posts
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Vancouver
dufFWant wrote: I think these methods are way beyond my ability :)
I think I’m going to stick with the commercially available solutions like the one I linked above. It says in the Globe Electric site that the battery (CR2) is good for five years. Is that realistic?
https://globe-electric.com/en/product/g ... ite-50027/
Hate to add to the complexity, but there's an issue you need to know about. Globe doesn't provide their own apps and servers, they rely on Tuya, whose Smart Life apps and services are widely used by the makers of cheap home automation devices. Tuya has lately decided that they are big enough to go it on their own, and they have started raising their own walled garden by cutting off outside services. So for example, your sensors supported by Tuya Smart Life can operate switsches and lights also supported by Tuya, but nothing from outside the Tuya sphere of control. It's still unresolved - Tuya has given in grudgingly to customer protests on a few things - like for example they cut off IFTTT in June, but then restored support this month after the protest. I have several devices supported by Tuya, including Globe devices, and I would hesitate to buy anything new from them until we see how the market shakes out.
Deal Addict
Sep 3, 2005
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dufFWant wrote: Hi folks,
I need some advice on a gadget...
I have a sump pit in my house that fills up and gets emptied by a sump pump. But sump pumps often fail, and I need some reassurance when they do.
I want to have a sensor on the pit when the level of water gets to a certain point.
I know there are products on the market that do that. However, the pit already has a little floatie sensor, which is wired to a legacy alarm sensor that no longer is use. The floatie does trigger the sensor (it lights up but has nowhere to send the signal as the alarm system is uninstalled). It’s wired to that sensor through simple two contacts. Kind like on (when connected) and off (when disconnected).
So, I’m looking for an updated sensor that will send an alert when the floatie is triggered (contacts are connected). Should be wifi capable, as I’d like to get a text or an email when triggered.

What products should I be looking for? Any recommendations?
Thanks!

I wouldn't bother trying to salvage the old sensor. Just get a wifi leak detector
https://www.bestbuy.ca/en-ca/product/d- ... 1/13041311

I have a home automation hub and I use a wireless battery powered water sensor in my pit.

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