Posted by skruglewicz in Low Power IoT Design Challenge on Aug 23, 2021 8:14:00 PM

BLOG# 3 - BPM Display - System Design

A Heart Rate Monitor Display project utilizing the PSoC 6S2 + AIROC Wi-Fi/Bluetooth Pioneer Kit

manufactured by CYPRESS - INFINEON TECHNOLOGIES (Part# CY8CKIT-062S2-43012)

This is my 3rd blog post for this Design Challenge: Low Power IoT Design Challenge

version 1.3

• This blog post will describe the design phase of the Challenge. It will include the Hardware and Software designs, that I came up with, to implement my idea.
• I will first describe the high level design, including all the components used to implement my idea.
• Then I'll describe the Wiring Diagram used to make the connection from the Arduino breadboard project to The PSoC6
  • I'll be adding 2 new wires to the wiring diagram from the Arduino design challenge.
  • I'll be using the jumper wires to get the BPM value from the Heart Rate Sensor attached to Arduino, to the pins on the PsoC 6 UART.

• Then for the Software Design section,
  • I'll include, UML Sequence Diagrams for the software pieces of the Design.
    • I'll be adding a new Task to the Arduino Sequence UML. Diagram
    • I'll include a new UML Sequence Diagram for the PSoC 6 code.

• • C/C++ and Python will be the languages used between the 2 projects.

• • • Python is used in a Bare Metal application on the Arduino.
    • I will note software used for the PSoC 6 design.
    • • FreeRTOS will be used as the operating system on the PSoC 6 using C/C++
• I finish the blog post with a summary, conclusions, and references that I used in this Design Phase.

Block diagram

This section, includes a Diagram the shows the components used in my project.

Design courtesy of element14 member Jan Crumps

• On the Arduino

1. • Send data with a serial connection

• On the PSoC6

• • Sleep
  • Receive Data
  • Wake Up
  • Publish data to AWS MQTT
    • For testing I'll be using MosQuiTTo MQTT as a broker.

      • I could not get this to work. I scratched it for the time being.

  • Sleep

System Level Flow Diagram

• The System design includes 2 decoupled designs that are connected together over a serial connection.
  • One design is taken from a previous design that I did for an element14 design challenge : Design for A Cause 2021
    • It uses the Arduino Nano 33 IoT Board 
    • Python is used in a Bare Metal application.
  • The second design is based on a project by an element14 member, Jan Crumps.
    • I will be using his design to implement my idea.
    • I experimented with Jan's series of blogs in my previous  blog Post
    • These blogs turned out to be using an Arduino connected to a PSoC 6 Kit (a different kit)  UART, so I decided to try and use his design.

Arduino Design

• As mentioned, a Heart Rate sensor is used in this design to get Heart Rate values to calculate Beats Per Minute.

• Python is used in a Bare Metal application on the Arduino.

• My previous design can be found here  Blog# 3 Beats Per Minute Nano - System Design , but I will augment section in this design blog with changes I had to ADD to the Circuit and Software in this blog.

• The design is already described in those blogs, so all I will do, is connect two jumper wires between the Arduino breadboard circuit and the PSoC 6.

PSoC6 Design

• As mentioned, this design is not my own, but is presented here  courtesy of an element14 member  Jan Crumps
• His design is portable and for the most part, can be used on any MCU using FreeRTOS.
• Four Blog Posts on UART, RTOS Scheduling and Message Queues, an AnyCloud MQTT Client  and Low Power are presented.
• The FreeRTOS operating system using C/C++, is the RTOS used for this design.

Wiring Diagram

• This section will shows the pins used on the Arduino and the PSoC6 to make the serial connection. The pins are connected using jumper wires.
• connect a jumper wire between a 3.3 V Arduino GND to a PSoC6 GND pin
• connect a jumper wire between the Arduino TX pin to a PSoC6 RX pin
• A wiring diagram with these jumper connections is described as follows.
  • This diagram was modified from the wiring design diagram from my previous design challenge.

•  

• Here is a pic of the 2 boards connected.
  • 

Software Design

Arduino Design

UML Sequence Diagram

• • This section, shows the logic of the flow of the Software used on the Arduino.
  • I modified the sequence diagram in the Arduino design to add the task of Writing the heart rate value to the serial port
  • It's a little messy, I marked the diagram by hand as the last step  in the sequene.
  • It comes after the BLINK action...
  • 

PSoC6 Design

UML Sequence Diagram

• This section, shows the logic of the flow of the Software used on the PSoC 6
• Derived from Jan Crumps code.
• The FreeRTOS Scheduler is used to Run the 2 major task
  • UART TASK
    • receives BPM values from the serial connection.
    • And sends the values in a message to the queue.
  • MQTT TASK
    • This task will connect to the cloud
    • The message is read from the queue and published to the cloud.
• 

Libraries

Arduino Design

• • • • The libraries used can be referenced in the blog

PSoC6 Design

• • • • For now I've taken a photo of the mdb_shared folder for my project.highlighting the known libraries.
      • 

Conclusions and Summary

• II tried to use all my notes and diagrams that I was conjuring up during my research phase in Blog#2.
• I decided to use a big part of Jan Crumps design for most of my design.
• I'm sure, I will tweak this blog as I try and implement my idea in the next Blog.
• Now onto the implementation