In this instructable I make use of a float switch and an arduino in combination with a LORA tranceiver to send an update when a waterlevel reaches a certain level. This node consumes very little current and can be used for a very long time on a coin cell battery.

Step 1: Get the Needed Parts

Parts:

float switch
arduino pro mini 3.3v 8mhz
esp breakout
rfm95
wire for antenna and connections (I use a 0.8mm solid core wire)
male to male jumper cables
female to female jumper cables
breadboard
CP2102
screw terminal

Tools:

Step 2: Making the Antenna

For the antenna I use some leftover cable of my 2x2x0.8mm or 2x2 20awg bus cable.
On the things network you can choose your tranceiver and antenna frequency band by country.
These are the lengths per frequencie:

868mhz 3.25 inches or 8.2 cm (this is the one I use)
915mhz 3 inches or 7.8 cm
433mhz 3 inches or 16.5cm

Step 3: Soldering the Esp Shield

Remove the resistors of the esp shield (see R1 to R3 in the red field)
Solder the rfm95 chip onto the esp shield.
Solder the pinheaders onto the esp shield
Solder the antenna onto the esp shield. Don't use without an antenna you can damage the shield.
If the pinheaders aren't soldered onto the arduino solder these too

Step 4: Wiring

In the image above you see the schematic wiring.

Step 5: Coding

I have included 2 files. One is the code without the LORA tranceiver and the second Is the one sending data via LORA.

Step 6: Conclusion

In this instructable you learned how to use a float switch with an interrupt in order to send a message to the LORA server. This way you can trigger by example an sms message or you can drive a pump to refill by example an IBC container.