node-red-node-arduino

This is a Node-RED Node module, to talk to an:

• Arduino: running "standard Firmata" firmware 2.2+, or
• ESP32: running "Configurable Firmata" 2.7+, or
• Raspberry Pi Pico: running "Configurable Firmata" 2.7+ firmware

through serial port. Typically plugged in to the host via USB to extend: I/O + analogue + I2C + OneWire + other Serial ports.

See the main documentation for details and examples of how to use this node.

Install

Either use the Menu - Manage Palette option, or run the following command in your Node-RED user directory - typically ~/.node-red

npm i --unsafe-perm node-red-node-arduino

Usage

The Firmata firmware must be loaded to the Arduino/RpiPico/ESP32 board. Recommended to use: Configurable firmata

You can add a firmware-specific name to each board before flashing/uplading, if you insert this line at setup:

void setup() {
    // Set firmware name and version. Do this before initTransport(), because some client libraries expect that a reset sends this automatically.
    Firmata.setFirmwareNameAndVersion("ArduinoFirmata-42-spec-name", FIRMATA_PROTOCOL_MAJOR_VERSION, FIRMATA_FIRMWARE_MINOR_VERSION); 
  	initTransport();

This will help identify from console-log which board is using which port.

You may check the "Log to console" checkbox at board setup page. (Default: Un-Checked.)
Use it on only at the beginning, for debugging errors. Turn Logging OFF (uncheck) in production to reduce log size and increase speed.

To view console Logs:

• If you started node-red in a consol, you will be able to see them there.
• Otherwise type in a console/terminal:> node-red-log

Note: On node-red's right sidebar (in your browser window) only errors are visible.

Main Board Settings:

These are hidden (non-visual) configuration Nodes called: Arduino: You can create a new ones, or choose from previously created. That will represent the chip or board connected.

Note: On Unix/linux systems, it is recommended to choose the COM port at "by-id" path, so it works always, no matter which USB port it gets plugged in. (It will look like this: /dev/serial/by-id/usb-Arduino_RaspberryPi_Pico_076461E62D414FE3-if00 )

Input Node

Connects to local board and monitors the selected pin for changes. Sends the value as msg.payload and the pin number as msg.topic to the next Node.

• Type: You can select either Digital, Pullup, Analogue, or String input type.

• Pin: a number between 0 and the highest GPIO

  • Warning: Analogue pins are counted from 0 ! (Not the actual GPIO port.) For example RPi-Pico: [0,1,2,3] (and not 26-29,) where A3 is the built-in Temp reader.

It only outputs on a change of the value. That's fine for digital inputs, but you can get a lot of data from analogue pins which you must then handle. For example:

• you could use a delay node, set to rate limit and drop intermediate values,
• or an rbe node to only report when it changes by a certain amount.

Also you can lower the reading rate by setting a higher: Sampling interval. Default read rate is: 250ms = 4 message/second. You can change that at the config panel of the board or during runtime. But not individually per pin.

Output Node

Connects to local board and writes to the selected pin.

You can select

• Digital - accepts 0, 1, true, false, on, off
• Analogue (PWM) - accepts Integer 0 to 255
• Servo - accepts Integer 0 - 180
• String - to send a String to the Arduino
• reset - to reset the board, if msg.payoload = true or 1
• Sampling interval - to set a new time (10ms - 65535ms) how fast analogue input data will be transfered

Digital, PWM, Servo will expects a value in msg.payload. The pin number must be set in the properties (config) panel before Deploy.

You can also send msg.payoload = "reset" to any Output Node without pre-configuring it, to reset the board. (Reset will set all output pins to LOW, and will stop sending analogue values) Note: it happens very fast. So if there is only a "LED blink", you will hardly notice anything, because "output" will work again after a few milliseconds. Analogue read (and maybe digital in too!) will stop completely until flow restart.

Note2 - some servos will not travel a full 180 degree range. (Maybe only accepting 30 - 150 degrees for example.) Please use the range node to scale the input appropriately.

Example

Simple flow to blink Pin: 13 (arduino LED). Change Pin to: 25 for RPi Pico LED

[{"id":"2db61802.d249e8","type":"arduino out","z":"65fc95b26b02d8a1","name":"","pin":"13","state":"OUTPUT","arduino":"d7663aaf.47194","x":240,"y":80,"wires":[]},{"id":"38edc285adb170c9","type":"inject","z":"65fc95b26b02d8a1","name":"","props":[{"p":"payload"}],"repeat":"0.31","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"true","payloadType":"bool","x":89.5,"y":40,"wires":[["2db61802.d249e8"]]},{"id":"1e034bcd12c2bf12","type":"inject","z":"65fc95b26b02d8a1","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"0.91","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"false","payloadType":"bool","x":89.5,"y":80,"wires":[["2db61802.d249e8"]]},{"id":"00793c4da9c669e2","type":"comment","z":"65fc95b26b02d8a1","name":"Set Port first!","info":"","x":250,"y":40,"wires":[]},{"id":"d7663aaf.47194","type":"arduino-board","device":"","name":"Led-Test-board","samplingInt":"500","log2consol":true}]