I have been doing a lot of investigative work on how Arduino (as an embedded MCU) and also Raspberry Pi (as an embedded CPU) have impacted the Internet of Things (IoT) and also the Industrial Internet of Things (IIoT or I2oT).

What I have found is that there is plenty of hobby level projects out there for both platforms and that for fast low-volume initial prototypes also both Arduino and Raspberry Pi are used, however for scaling up larger projects, I noticed that there was a shift away from both of these into the custom ARM cores.

Now ARM supports both single and multi-core embedded MCU as their Cortex M series (M0, M1, M3, M4, and M7) https://en.wikipedia.org/wiki/ARM_Cortex-M

as well as their single and multi-core embedded CPU technologies as their Cortex A series (A3x, A5x, A7x) https://en.wikipedia.org/wiki/ARM_Cortex-A

Just wondering if anyone is using the Arduino or Raspberry Pi platforms on a larger scale ( > 100 pieces or nodes) for IoT or IIoT ?

Your comments, opinions, and experiences are appreciated. - Thank you very much !