node-arduino-machine-control

CREDITS:

Arduino code with nodeJS OTA updater

The Arduino OTA code was inspired by and should be mostly credited to

@enfieldcat [https://github.com/enfieldcat]

Based on the article (s)he published here: https://conferre.cf/arduino/ota_updater.php

Purpose

This is a machine control application that allows control of tasks from a node.js Express application. The basic concept is that the arduino client polls the node.js server for tasks to do, which are returned in a JSON array and processed by the client.

Included in the node client is the ability to dispatch firmware versions to the client to install to allow remote updating of clients.

nodeJS app:

To start the node app, run the following at the command line

% npm start

To dispatch task(s), uncomment lines from the ./src/services/tasks.js file that begin with push().

arduino app:

The arduino app is in:

./arduino/arduino_client.

You can modify the Arduino app in VS Code or the Arduino app. To publish versions for OTA updating, Exporting a Compiled Binary from the arduino app. The .bin file will be saved into the same folder. Drag the .bin file into the appropriate version folder under

./src/services/ota/bin

The OTA updater will look for a folder with the version number and send the .bin file in that folder to the updater.

This code was built using an ESP32 with built-in wifi. I have no idea what changes, if any, are necessary for other device flavors.

IDE

The node/arduino code was built using VS Code. To learn more about how to use VS Code with Arduino, I recommend checking out

https://maker.pro/arduino/tutorial/how-to-use-visual-studio-code-for-arduino

Tasks

The tasks that the arduino code knows how to deal with are in

./src/services/tasks/taskPayloads.js

The basic structure of a task object is:

{
    taskId: '12345',  // any string or uuid will do
    task: 2           // integer ID or a task.  The arduino looks for integers.
    customValue1: 'something the taks recoginzes',
    customValueN: 123  // custom values are passed into the task on the adruino.
}

Heres the Arduino code that can read a custom field called duration :

{
  taskId: uuid(),
  task: SET_LOOP_DELAY, // SET_LOOP_DELAY = 3
  duration: 1000 // Set the main loop delay to 1 second
}

void setLoopDelay(JsonObject task){
  if(DEBUG) Serial.println("setLoopDelay called");

  int delay = task["duration"];  // this is a custom field
  const char* taskId = task["taskId"].as<char*>();

  loopDelay = delay;
  ack(taskId);
}