nextion

Communicate with ITEAD's Nextion HMI Devices

pic of nextion device

Status

[x] Support all non-success/error return values
[ ] Support all success/error messages
[ ] Send operation commands
[ ] Reasonable, high-level API; don't require user to send raw commands
- [ ] System-level abstraction
- [ ] Component-level abstraction
[x] Tessel 2 support
[ ] Remove serialport dependency

Basic Usage

COM Port, USB-to-UART adapter, etc.

const Nextion = require('nextion');

// CH340G usually shows up at this path on macOS
Nextion.fromPort('/dev/tty.SLAB_USBtoUART')
  .then(nextion => {
    console.log('Listening...');

    nextion.on('touchEvent', data => {
      console.log(data);
    });
  });

For port auto-detection, try:

const Nextion = require('nextion');

Nextion.create()
  .then(nextion => {
    // do exciting stuff here
  });

Tessel 2

const tessel = require('tessel');
const Nextion = require('nextion/minimal');

const uart = new tessel.port.A.UART({
  baudrate: 9600
});

Nextion.fromSerial(uart)
  .then(nextion => {
    // Yipper McCheese!
  });

The nextion/minimal module is for resource-constrained systems; it's compressed and does not include source maps.

Compatibility

As long as the argument passed into Nextion.fromSerial is a Duplex stream or a duck-typed one (a la serialport), you should be able to use it. Hack away!

API Docs

TODO

Development

Use environment variable DEBUG=nextion* for debug output.
To run end-to-end tests against a connected device, read test/e2e/README.md, then execute yarn test:e2e.
For serial port debugging, use DEBUG=nextion*,serialport.

Events

The Nextion instance (nextion) in above examples is an EventEmitter. If the device sends any of these over the UART channel, the Nextion instance will emit a corresponding event (w/ data, if any).

Return Values (Table 2)
- touchEvent: Touch event return data
- pageId: Current page ID
- touchCoordinate: Touch coordinate data
- wake: Touch event in sleep mode
- stringData: String variable data
- numericData: Numeric variable data
- autoSleep: Device automatically enters sleep mode
- autoWake: Device automatically wakes from sleep mode
- startup: Successful system startup
- cardUpgrade: Start SD card upgrade
- transmitFinished: Data transmit finished
- transmitReady: Ready to receive data transmission

TODO: Describe shape of data for data-emitting events.

Motivation

Send & receive events over UART to a Nextion device (hardware reference)
Support Tessel 2
Support USB-to-UART serial adapters for debugging
Endgame: combine a Tessel 2 w/ a Nextion to design/implement a (mainly) JS-based home environmental control panel/dashboard.

Future:

Ensure support on popular ARMv6/7/8
Ensure support on popular (non-Tessel) MIPS devices
Interface into GUI designer commands
Johnny-Five support?

Notes

Johnny-Five

Johnny-Five support is problematic, because:

Only "enhanced" Nextion models have any GPIO pins (8 PWM-capable pins)
All communication w/ the device is over UART, so an IO plugin would be extremely wonky
No ADC, as far as I know
Any I2C or SPI communications would probably need to be handled by a daughter board

ARM

If the serialport module supports the architecture, this module should work out-of-the-box, meaning RPi's and BBB's are theoretically covered.

MIPS

This shouldn't be too bad, because the Tessel 2 is MIPS-based, but we require Node.js v4. Other MIPS-based boards I've used have had trouble getting it compiled, packaged, or running at a respectable speed.