Answer
Perform the following steps:
- An Internet search for
low-power microprocessor
brings up a selection of processors from manufacturers including STM, Analog Devices, Texas Instruments, Microchip Technology, and several others. - A second search for
embedded cellular modem
produces a list of cellular modems suitable for this application. Some of these devices are in the form of a system-on-module (SoM), incorporating the RF modem with a programmable processor core in a single module. - The MultiTech Dragonfly Nano SoM (https://www.multitech.com/brands/multiconnect-dragonfly-nano) appears to be suitable for this application. This device is available for US$103.95 and integrates an ARM Cortex-M4 processor for hosting user applications. The Dragonfly Nano provides I/O interfaces including a serial UART, USB, I2C, SPI, 9 analog inputs, and up to 29 digital I/O pins. The Cortex-M4 contains 1 MB of flash memory and 128 KB of RAM.
- The Dragonfly Nano documentation states...