This project consists of developing a simple device in order to count pulses and sending a report to a backend using NB-IoT.
The main requirements of the whole system are:
- NB-IoT communication.
- The device has to be as small as possible.
- The device has to be able of sending 2 sessions during 6 months everyday, so the total number of sending sessions are 365, using a lithium primary battery non-rechargeable.
I’ve selected this module BC66 by Quectel with the following features:
- The power supply is from 2.1 to 3.63 Volts, it is designed for being connected to a lithium primary battery directly.
- For purchases over 100k units the module can be bought with an internal eSIM WLSCP.
- The BC66 is provided by a 32-bit ARM Cortex-M4 RISC 78MHz in order to execute the application user. This microprocessor has a user app code Space of 200KB, as well as a RAM space of 100KB static memory and 300KB dynamic memory.
- The BC66 module can be easy wake-up via external interrupt from deep sleep mode.
We were able to design a small circular PCB of 60 mm with everything necessary for working properly: NB-IoT module, microcontroller, antenna and battery. I was the project manager in charge of the whole project: electronic design, schematics, PCB, antenna adaptation and power consumption approach.
Used technologies: C, NB-IoT, Antenna Design and Altium Designer.