We have a lake next to our house in Sweden that we swim in and I monitor (for a couple of houses that share it) the surface (~15cm) and submerged (~1m) temperature using Ecowitt WN34 sensors. The lake is about 100-200m from the tower that houses a GW1100 to receive the measurements. Our winter gets down to -20C sometimes with snow and lake freezing, so we skate on the ice. For next winter, I'll add an Ecowitt LDS01 sensor for snow depth. So far we have some Ecowitt consoles but I also dump the GW1100 output through MQTT and surface it on a custom IOT device and a webpage that people can use in and outside of the local WiFi network.
I'd like to add an ice depth sensor. I can't see there is a viable one off the shelf. Yet to some degree, it a simple DIY solution looks possible.
Firstly, any off the shelf products I could use? They don't need to be Ecowitt.
Secondly, DIY solution I think could involve an array of 128 NTC thermistors at 1cm spacing, all voltage divider through 8x 16 channel mux and ADC into a uC like an ESP32 that I have experience with, or a PIC for even lower power consumption. I can have a PCBs built so 8 PCB are daisychain with some JST connectors and hold the NTC at precise points, then I can bed this in an acrylic tube fill with epoxy resin so it is entirely watertight and have small holes that leave just the heads of the NTC exposed, and use this "stick" in the water (attached to a floating dock we have, so the position to water level is constant) to measure the temperature levels and detect the ice boundary. This will also eliminate the WN34s and I can use a point to point Lora or something to the tower so it's a bit more robust (I get some dropouts on the WN34's). I think this is far better than trying to use some sort of ultrasonic/etc solution. The microelectronics and software are pretty simple.
Any experience/thoughts on this before I go down this road (aim to do it in the next 6 months and install/test before winter).
