MicroPython

An introduction to building cheap IoT devices with MicroPython. Talk given at BrightonPy on 12th October 2017.

Transcript

1. MicroPython Jamie Matthews BrightonPy October 2017
2. WE ARE HIRING Python/Django JavaScript/React
3. Internet of Things http://twitter.com/internetofshit
5. 16Mhz 32KB memory
6. Lots of IO!
7. No network :(
10. 1.2GHz 1GB memory WiFi + Ethernet Runs Linux
13. Time passes… happens…
14. Motivation
15. * not my house
17. What we are trying to build: A standalone temperature and humidity sensor that publishes readings into Home Assistant. Cheap, quick and easy.
18. 80MHz 128Kb memory WiFi! ESP8266
19. Less than £4!
21. IT RUNS PYTHON!
22. “MicroPython is a lean and efficient implementation of the Python 3 programming language…” “…that includes a small subset of the Python standard library…” “…and is optimised to run on microcontrollers and in constrained environments.” Bytecode compiler + runtime Runs directly on the microcontroller hardware - no Linux
23. Brief aside: MQTT
24. Brief aside: MQTT Raspberry Pi Sensor + ESP8266 Home Assistant
25. Brief aside: DHT11 Temperature + humidity sensor ~ £1.40 including cable
26. Tip: Don’t bother trying to do any of this on a Mac. Buy a Raspberry Pi and do this over SSH (or something)
27. pip install esptool
28. esptool.py --port /dev/ttyUSB0 erase_flash
29. esptool.py --port /dev/ttyUSB0 erase_flash
30. esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 ~/esp8266-20170823-v1.9.2.bin
31. apt-get install picocom picocom -b 115200 /dev/ttyUSB0 >>> print('omg') omg REPL!
32. pip install adafruit-ampy ampy --port /dev/ttyUSB0 put main.py
33. from time import sleep from umqtt.robust import MQTTClient import dht import machine import network import ubinascii import ujson WIFI_SSID = "<password>" WIFI_PASSWORD = "<ssid>" MQTT_BROKER = "192.168.86.126" # static ip of pi MQTT_USERNAME = "<username>" MQTT_PASSWORD = "<password>" SENSOR_PIN = 4 CLIENT_ID = b"esp8266_" + ubinascii.hexlify(machine.unique_id()) MQTT_TOPIC = b"home" + b"/" + CLIENT_ID SECONDS_BETWEEN_READINGS = 600 def connect_to_wifi(): sta_if = network.WLAN(network.STA_IF) if not sta_if.isconnected(): print('connecting to network...') sta_if.active(True) sta_if.connect(WIFI_SSID, WIFI_PASSWORD) while not sta_if.isconnected(): pass print('network config:', sta_if.ifconfig()) def setup_mqtt_client(): client = MQTTClient(CLIENT_ID, MQTT_BROKER, user=MQTT_USERNAME, password=MQTT_PASSWORD) client.connect() print("Connected to {}”.format(MQTT_BROKER)) return client def setup_dht_sensor(): return dht.DHT11(machine.Pin(SENSOR_PIN)) def send_readings(mqtt_client, dht_sensor): dht_sensor.measure() temperature = dht_sensor.temperature() humidity = dht_sensor.humidity() print("Temperature: {}, humidity: {}".format(temperature, humidity)) payload = ujson.dumps({"temperature": temperature, "humidity": humidity}) mqtt_client.publish(MQTT_TOPIC, payload) def main(): connect_to_wifi() mqtt_client = setup_mqtt_client() dht_sensor = setup_dht_sensor() while True: send_readings(mqtt_client, dht_sensor) sleep(SECONDS_BETWEEN_READINGS) if __name__ == "__main__": main() ~ 60 lines
34. from time import sleep from umqtt.robust import MQTTClient import dht import machine import network import ubinascii import ujson
35. WIFI_SSID = "<password>" WIFI_PASSWORD = "<ssid>" MQTT_BROKER = "192.168.86.126" # static ip of pi MQTT_USERNAME = "<username>" MQTT_PASSWORD = "<password>" SENSOR_PIN = 4 CLIENT_ID = b"esp8266_" + ubinascii.hexlify(machine.unique_id()) MQTT_TOPIC = b"home" + b"/" + CLIENT_ID SECONDS_BETWEEN_READINGS = 600
36. def main(): connect_to_wifi() mqtt_client = setup_mqtt_client() dht_sensor = setup_dht_sensor() while True: send_readings(mqtt_client, dht_sensor) sleep(SECONDS_BETWEEN_READINGS) if __name__ == "__main__": main()
37. def main(): connect_to_wifi() mqtt_client = setup_mqtt_client() dht_sensor = setup_dht_sensor() while True: send_readings(mqtt_client, dht_sensor) sleep(SECONDS_BETWEEN_READINGS) if __name__ == "__main__": main()
38. def connect_to_wifi(): sta_if = network.WLAN(network.STA_IF) if not sta_if.isconnected(): print('connecting to network...') sta_if.active(True) sta_if.connect(WIFI_SSID, WIFI_PASSWORD) while not sta_if.isconnected(): pass print('network config:', sta_if.ifconfig()) (boilerplate)
39. def main(): connect_to_wifi() mqtt_client = setup_mqtt_client() dht_sensor = setup_dht_sensor() while True: send_readings(mqtt_client, dht_sensor) sleep(SECONDS_BETWEEN_READINGS) if __name__ == "__main__": main()
40. def setup_mqtt_client(): client = MQTTClient( CLIENT_ID, MQTT_BROKER, user=MQTT_USERNAME, password=MQTT_PASSWORD) client.connect() print("Connected to {}".format(MQTT_BROKER)) return client
41. def main(): connect_to_wifi() mqtt_client = setup_mqtt_client() dht_sensor = setup_dht_sensor() while True: send_readings(mqtt_client, dht_sensor) sleep(SECONDS_BETWEEN_READINGS) if __name__ == "__main__": main()
42. def setup_dht_sensor(): return dht.DHT11(machine.Pin(SENSOR_PIN))
43. def main(): connect_to_wifi() mqtt_client = setup_mqtt_client() dht_sensor = setup_dht_sensor() while True: send_readings(mqtt_client, dht_sensor) sleep(SECONDS_BETWEEN_READINGS) if __name__ == "__main__": main()
44. def send_readings(mqtt_client, dht_sensor): dht_sensor.measure() temperature = dht_sensor.temperature() humidity = dht_sensor.humidity() payload = ujson.dumps({ "temperature": temperature, "humidity": humidity }) mqtt_client.publish(MQTT_TOPIC, payload)
50. NO SOLDERING!
51. ESP8266 x5 £18.99 Sensor x5 £7.19 USB power plug x5 £9.25 6” USB cable x5 £6.95 Plastic project box x5 £8.75 Total £51.13 Per unit: £10.23
52. GO FORTH AND MAKE STUFF WE ARE HIRING Python/Django JavaScript/React