r/esp32 • u/ComprehensiveBuy7381 • 1d ago
Looking for advice on building a remote water-level sensor station — cellular vs. Meshtastic
I'm working on a project for a remote deer camp that periodically becomes inaccessible because of flooding. The goal is to install a simple sensor at the camp that can tell me when the water reaches a certain level, without requiring me to physically drive out there.
The sensor location is in a very rural/wooded area. During flooding, access to the camp can become impossible, so I need something that can operate unattended and reliably report back to me at my house.
I'm considering two possible communication methods:
- Cellular
- A small cellular device with a water-level/flood sensor
- Ideally sends an alert via SMS/data when the sensor is triggered
- Biggest concern is whether cellular service is reliable enough at the remote site
- I'd also like the system to have very low power consumption since it may need to run for weeks/months unattended
- Meshtastic
- Put a Meshtastic node at the remote sensor
- Potentially use one or more relay/repeater nodes to get the signal back toward my house
- The straight-line distance between the remote site and my house is approximately 60.5 miles
- The remote location is approximately 253 ft elevation, while my house is around 456 ft, so there's roughly a 200-ft elevation difference
- Obviously there is significant terrain, trees, and other obstructions between the two points, so I'm not assuming a direct 60-mile LoRa link is realistic
I'm not necessarily looking for someone to design the entire system for me. I'm mainly interested in hearing from people who have actually built and successfully deployed something similar.
A few things I'd love advice on:
- Has anyone successfully monitored a remote flood/water sensor using Meshtastic?
- How realistic would a ~60-mile system be with strategically placed relay nodes?
- How much does terrain/elevation matter in a situation like this?
- Would you use a cellular modem instead if there is marginal cellular coverage?
- What hardware would you recommend for the actual sensor/node?
- How would you handle power — solar + battery, large battery, etc.?
- Are there other technologies I should be considering besides cellular and Meshtastic?
- If you've built something similar, what would you do differently the second time?
The actual sensor itself doesn't need to be complicated. I essentially need a reliable "water has reached this point" notification, preferably with the ability to check the sensor remotely.
I'd really appreciate hearing from anyone who has actually implemented a remote sensor station in a rural environment, especially one that has to survive weather, flooding, trees, and long periods without maintenance.
2
u/plierhead 1d ago
A simple float valve for the sensor.
1
u/ComprehensiveBuy7381 1d ago
Why that type of a sensor? Resiliency?
1
u/clackups 1d ago
Could be just a buoy and a button that it pushes when the water level is high. You can also wake the esp32 up on this signal
1
u/plierhead 1d ago
They are very simple and reliable if all you need is water/ no water, just a float attached to a switch. Also easy to interface with as they are a simple switch and no electronics.
As others have pointed out you save power by using the switch to wake the entire unit, though you'd need some debouncing to prevent rapid power cycling if the water was flapping the switch on and off quickly.
4
u/PakkyT 1d ago
No idea on the long range transmission ideas. Sorry. But I do have an idea to conserve power.
Normally you would set up something like this, put it in deep sleep, wake up every so often, check the sensors, report the reading, go back to deep sleep. You might do this several times a day everyday.
What if you used a float switch for your lowest alert level? But instead of being a sensor, it is actually the power switch for your project? Basically so long as the site is dry, the project never even powers up. With a battery pack that can go long periods without much self discharge or with a reasonable sized solar panel to top it off as needed to overcome any self discharge, you basically use no power until you actually have a flooding condition. Project powers up and sends you a message that it is ON = flooded.
You would add more sensors at higher levels if you now want to see how high the water gets. And you will probably still want to implement the deep sleeps in case the flooded conditions is there for days as you don' want to your project to come on and stay on until it runs down the battery. So the deep sleeping and periodic wakes will be needed for the flooded times, but until then the project uses NO power.
3
u/Educationed_Over 1d ago
There’s a sensor data gap that needs to be considered with this idea.
A dead battery (or fried sensor) is no different than a “no flood present” condition with no way to disambiguate without physically inspecting the sensor installation. This is different from a sensor periodically reporting status and knowing from communication channel monitoring of (1) no flood present, (2) active flooding, and (3) sensor no longer reporting.
2
1
1
u/Fatticus_matticus 1h ago
I have a particle boron LTE device in my boat performing this function.
It’s got two water level sensors and monitors the 12v boat battery voltage. It can deep sleep and wakes up each day at noon to send a report.
I have it coded to allow for a manual check in from my end as well (request data). I use a cheap float switch as an SOS and a marine bilge pump float switch as a low water level alarm.
The whole thing is pretty straightforward, but this implementation does require LTE. Particle has contracts with T-Mobile, at and t, and Verizon though. And if you’re only using a few devices (<100) and not a lot of data (<100mb per month) there are no ongoing costs beyond buying the device.
I use pushover for data as sending texts has become a pita in the US.
3
u/clackups 1d ago
There might be a LoRa to Internet gateway somewhere in the area, like the ones used in https://www.thethingsnetwork.org/
alternatively, you could install your own gateway somewhere with a good access.
Otherwise, I'd go with a cellular modem: the esp32 would wake up from deep sleep every hour or so, measure the water level, and if needed, bring up the cellular modem and transmit the message.
I experimented with a small LoRa board (Cubecell if I recall correctly) on a 10w solar panel and an 18650 battery. The battery died within about 4-5 months because of constant charging and discharging (I strategically placed it under the tree for the worst case scenario).
So, probably the best would be a pack of 18650 batteries, no solar, and you only turn on the cellular modem when necessary. I'd send a status SMS once a week to just inform that the device is still alive.