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The DS Mini is based on a PIC32MX150F128 processor, with 128K Flash and 32K RAM. The BLE transceiver is a RN4871 module, with the protocol stack in firmware. So processor memory is not much of an issue. The local storage is kind of cool; it’s an EMC1001 with 16K of static RAM. That allows fast access with minimal power consumption. Upon power-down, the entire contents of RAM is written to EEPROM in a single blast, powered by a capacitor. At power-up, RAM is re-loaded automatically.

Since this is a low-end device, it doesn’t support professional sensors such as the SD1-12 type. Its intended to be cheap and easy to set up. On a smartphone you can scroll through a list of known sensor types, and a couple of taps will configure the data logger.

I plan to use LoRaWAN on the mid-range and hi-end versions. In that case I’ll be using a RN2903 transceiver for long range wireless communication at 915 MHz, also with an internal protocol stack. It will be interesting to see what sort of range is possible close to the moist earth, or under a canopy as you suggested. I really appreciate your input on sensor types; since my background is in electronics and software, not environmental science.