Hello Twin (Backend + MCU)

Video

Backend and microcontroller part of a minimum digital twin example.

Unity part here

Table of Contents

• Requirements
• Quickstart
  • Arduino and VSCode
  • Python (not needed for server)
  • InfluxDB
  • Node
• Heads-Up

Requirements

• Computer
• Arduino UNO
• Internet

Quickstart

Arduino and VSCode

Install VSCode

Install Arduino IDE

Open VSCode

Install recommended extensions (most importantly Arduino)

Run Arduino: Board Config

Choose Arduino UNO (or the type you have on hand)

Run Arduino: Select Serial Port and choose your Arduino's port
Remember the port, as we'll need it later

Open DemoTwin.ino

Run Arduino: Initialize

Upload DemoTwin.ino to your board

Run Arduino: Change Baud Rate and ensure it's set to 115200

Run Arduino: Open Serial Monitor

If successful, you should be able to run Arduino: Send Text to Serial Port, and turn the LED on and off by sending H and L

Run Arduino: Close Serial Monitor

Python (not needed for server)

Install Anaconda (or any variant you prefer)

Open up your terminal, and run these commands:

conda create --name arduino python=3.7

conda activate arduino

conda install pyserial

Choose the new Arduino environment as the default Python interpreter in VSCode, by running Python: Select Interpreter.

Create a file in the project root called .env.

Set the correct COM-port in .env (COM5 in my case), like so:

COM="COM5"

Open serial_test.py in VSCode.

Run cell by cell with IPython.

InfluxDB

Create a free InfluxDB-account

Choose Azure as your bucket if prompted and you're not sure.

Go to Data -> Buckets and press Create Bucket.
Note: Load Data, Data and Load your data are equivalent.

Call it HelloTwin Bucket.

Go to Data -> Tokens and press Generate Token, and pick Read/Write Token.

Set description as HelloTwin and enable read and write access to HelloTwin Bucket.

Click on the token you created and Copy to Clipboard.

Add the following to your .env-file, with your info (can be found in all examples for loading data under Data -> Client Libraries):

BUCKET="HelloTwin Bucket"
URL="https://your-thingy-thang.influxdata.com" # Replace
TOKEN="Th3T0k3nY0uJu5tC0pI3d" # Replace
ORG="[email protected]" # Replace

Node

Add a port to your .env-file:

PORT="8080"

Install Node (recommended version).

Install Yarn:

npm i -g yarn

Install dependencies:

yarn

Run development server:

yarn run dev

You'll likely get some errors - don't worry.

Open src/index.ts and save the file.

You can test queries with Insomnia (or Postman, if you prefer).

Heads-Up

If you get permission denied when doing anything COM-port related, make sure you close all active processes using the COM (e.g., Interactive Python or the Arduino Serial Monitor), and try again.

This project formats Python code with black, so accept installing it if prompted by VSCode, if you want auto-formatting.

In general, you should accept what VSCode recommends you to install, unless you know what you're doing.