ESP8266 and MicroPython - Part 2
Beside HTTP POST
You have to make a decision: Do you want to pull or to poll
An example for pulling is aREST. This is a great way to work with the ESP8266 based units and the Ardunio IDE.
MQTT
You can find a simple examples for publishing and subscribing with MQTT in the MicroPython
The example below is adopted from the work of @davea/config.json
which stores the configuration details. The ESP8266 device will send the value of a pin every 5 seconds.
import machine
import time
import ubinascii
import webrepl
from umqtt.simple import MQTTClient
# These defaults are overwritten with the contents of /config.json by load_config()
CONFIG = {
"broker": "192.168.1.19",
"sensor_pin": 0,
"client_id": b"esp8266_" + ubinascii.hexlify(machine.unique_id()),
"topic": b"home",
}
client = None
sensor_pin = None
def setup_pins():
global sensor_pin
sensor_pin = machine.ADC(CONFIG['sensor_pin'])
def load_config():
import ujson as json
try:
with open("/config.json") as f:
config = json.loads(f.read())
except (OSError, ValueError):
print("Couldn't load /config.json")
save_config()
else:
CONFIG.update(config)
print("Loaded config from /config.json")
def save_config():
import ujson as json
try:
with open("/config.json", "w") as f:
f.write(json.dumps(CONFIG))
except OSError:
print("Couldn't save /config.json")
def main():
client = MQTTClient(CONFIG['client_id'], CONFIG['broker'])
client.connect()
print("Connected to {}".format(CONFIG['broker']))
while True:
data = sensor_pin.read()
client.publish('{}/{}'.format(CONFIG['topic'],
CONFIG['client_id']),
bytes(str(data), 'utf-8'))
print('Sensor state: {}'.format(data))
time.sleep(5)
if __name__ == '__main__':
load_config()
setup_pins()
main()
Subscribe to the topic home/#
or create a MQTT sensor to check if the sensor values are published.
mosquitto_sub -h 192.168.1.19 -v -t "home/#"
sensor:
- platform: mqtt
state_topic: "home/esp8266_[last part of the MAC address]"
name: "MicroPython"
@davea