Nextion serial client 
Lightweight Python 3.6+ async library to control Nextion displays.
Installation
Pypi
pip3 install nextion
Simple usage:
import asyncio
import logging
import random
from nextion import Nextion, EventType
class App:
def __init__(self):
self.client = Nextion('/dev/ttyS1', 9600, self.event_handler)
# Note: async event_handler can be used only in versions 1.8.0+ (versions 1.8.0+ supports both sync and async versions)
async def event_handler(self, type_, data):
if type_ == EventType.STARTUP:
print('We have booted up!')
elif type_ == EventType.TOUCH:
print('A button (id: %d) was touched on page %d' % (data.component_id, data.page_id))
logging.info('Event %s data: %s', type, str(data))
print(await self.client.get('field1.txt'))
async def run(self):
await self.client.connect()
# await client.sleep()
# await client.wakeup()
# await client.command('sendxy=0')
print(await self.client.get('sleep'))
print(await self.client.get('field1.txt'))
await self.client.set('field1.txt', "%.1f" % (random.randint(0, 1000) / 10))
await self.client.set('field2.txt', "%.1f" % (random.randint(0, 1000) / 10))
await self.client.set('field3.txt', random.randint(0, 100))
print('finished')
if __name__ == '__main__':
logging.basicConfig(
format='%(asctime)s - %(levelname)s - %(message)s',
level=logging.DEBUG,
handlers=[
logging.StreamHandler()
])
loop = asyncio.get_event_loop()
app = App()
asyncio.ensure_future(app.run())
loop.run_forever()Nextion constructor parameters
url: str # serial dev
baudrate: int # baud rate
event_handler: typing.Callable[[EventType, any], None] # Event handler function
loop=asyncio.get_event_loop() # your own event loop
reconnect_attempts: int = 3 # how many times to try to retry command in case of failure
encoding: str = 'ascii' # Nextion encoding
Nextion parameters
Encoding
You can update encoding on fly (This changes encoding of serial communication only):
client.encoding = 'latin-1'
Get current set encoding (Not fetched from the device)
print(client.encoding)
Event handling
event_handler method in the example above will be called on every event comming from the display.
| EventType | Data | Data attributes |
|---|---|---|
| TOUCH | TouchDataPayload | page_id, component_id, touch_event |
| TOUCH_COORDINATE | TouchCoordinateDataPayload | x, y, touch_event |
| TOUCH_IN_SLEEP | TouchCoordinateDataPayload | x, y, touch_event |
| AUTO_SLEEP | None | - |
| AUTO_WAKE | None | - |
| STARTUP | None | - |
| SD_CARD_UPGRADE | None | - |
For some components in the Nextion Editor you need to check Send Component ID for required event.
Firmware uploading
If you installed the library you should have nextion-fw-upload command in your PATH.
nextion-fw-upload -hOtherwise use next command in the root of the project:
python -m nextion.console_scripts.upload_firmware -hUsage (check with option -h)
usage: nextion-fw-upload [-h]
[-b {2400,4800,9600,19200,38400,57600,115200,230400}]
[-ub {2400,4800,9600,19200,38400,57600,115200,230400}]
[-v]
device file
positional arguments:
device device serial port
file firmware file *.tft
optional arguments:
-h, --help show this help message and exit
-b {2400,4800,9600,19200,38400,57600,115200,230400}, --baud {2400,4800,9600,19200,38400,57600,115200,230400}
baud rate
-ub {2400,4800,9600,19200,38400,57600,115200,230400}, --upload_baud {2400,4800,9600,19200,38400,57600,115200,230400}
upload baud rate
-v, --verbose output debug messages