Add remotely located sensor

Projects General Guidance
1

Hi everyone, looking for your guidance on adding a sensor, remotely located from existing Arduino MKR 1010 board.

The background: This board controls a koi pond waterfall pump. I use a relay shield that drives a 12 volt relay, which in turn switches a solid state relay to engage the 110 volt AC power.

The MKR board is configured as an Arduino Thing, using a IOT dashboard. I’ve deployed a dashboard timer to run the pump on schedule. There are two toggle switches, one virtual and one physical. Both are configured identically in function, to override the auto schedule and run / stop the pump manually (short press). Also, they may engage or or reset a failure state (long press). When in failure state, the timer controlled settings are ignored and the waterfall is idle.

I use the MKR board with a float sensor that monitors the water volume of the nearby filter barrels. When the water rises in the barrel (which indicates filter media cleaning is needed), the fail mode is activated.

The new ask: The koi pond is about 30-40 feet from the physical location of the Arduino and filter assembly. I would like to add another float sensor onto the pond. The goal is to ensure water level doesn’t drop below preset level. Low water may indicate a hose fitting failure (which has happened twice over its 20 year history). I want to ensure the waterfalll pump stays dormant, via the failure state, if water is low. And thereby save the fish.

How do my readers suggest I attach this new float sensor to my existing Arduino / Thing / dashboard? I’d like to avoid stringing and burying cable. If that is off the table, I can think of these approaches:

  1. A new pondside Arduino driving a float sensor, which communicates with the main Arduino via BlueTooth;

  2. A new pondside Arduino driving a float sensor, which communicates to the IOT Thing and dashboard via WiFi;

Curious what this group thinks. Thank you for your consideration and insight to my question. Happy to answer questions or provide additional detail.

2

It completely depends on two things, one is simply distance, Bluetooth is good for 10ft to 30ft. Wifi up to 300 ft. The other is what kind of Bluetooth is on each board, Classic or BLE. The Bluetooth needs to be the same, as far as I know.

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3

You say remote… can that be wired or must be wireless ?

If wired is ok, My first attempt would be an opto isolated contact closure to ground.

No extra components, simple and reliable.

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4

The very best way to do that is have the float valve directly interrupt the power to the waterfall pump, in case of low water. Float valves rated for AC pumps (e.g. as storage tank sensors) are available to detect either low or high water levels.

That is cheaper, much simpler and much more reliable that pushing the float valve status into the network.

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5

The MKR 1010 is classic I would get a second one of classic type. But I am unsure how to make the two arduinos talk to each other I’ve tried to find content but have struggled to find a thread that discusses in detail how to do this. Would appreciate any insight.

6

Yes, these are valid points. Just not nearly as much fun as doing this with my own creation. Interested in crafting my own way, if I can pull it off.

7

They don’t need to talk to each other…
If wired,

Float switch - long wire pair - optocoupler - to Arduino.

Play with a voltage divider to find the best ‘return voltage’ from the switch.
All done.

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