I have been pondering on a project for multiple weeks now and I am kind of lost. I have multiple plausible solutions, but none is really 'the' solution in my eyes.
What are we talking about? For now I have a arduino mini pro connected to 3 DS18B20, a DHT22 and a RFM95 lora radio. This unit monitors one of my beehives and sends temperature and humidity to TheThingsNetwork.
I have the DS sensors connected to different pins, so I'm sure which sensor is which. I change sensors often when I have to replace stuff in the hive, so sensor id's can change. Pin1 is box1, pin 2 is box2... I can't just loop through all sensors as far as I know.
As I have hives in places that don't have TTN coverage I am looking towards GPRS to send my data. As these modules are quite expensive (If I would want to monitor 20 to 50 hives in the future), I want to combine multiple hives 4 or 6 for example) on one node.
Things I have thought of:
Connect all DS18 sensors to one arduino pro mini, 1 pin per hive, 3 to 6 sensors per pin. Hard code sensor ID's so I know where which sensor is. No easy way to replace sensors without reprogramming or using sd card with sensor id's
Let a arduino pro emulate a 1- wire slave. Looked into this, but this seems beyond my skill level to build from cratch.
Build a arduino pro mini I2C slave which communicates the sensor data to the master adruino. Hives ar not more that a few meters apart, so this should be a plousible solution.
Connect 3 to 6 sensors to a DS2482-800 1-wire master chip, 1 chip per hive. Almost gave up on this as there no 'decent' libraries that I could find. Almost gave up on this until i found this one: GitHub - mario67/DS2482MM: An Arduino library for DS2482-800 and DS2482-100 (Maxim).
I have been thinking about wireless solutions as Bluetooth or RF, but this would mean the master should always on to be able to receive data from all the slaves
Is there anything I overlooked, some miracle solution I didn't think of? Or does anybody have any pointers for the things I listed above.
Ooh did I mention it has to be low power? I'm using ds16850 batteries.
Thanks for taking the time to read through all this. Any hint/tips/.. are greatly appreciated!