IoT: Internet of Things with Python

IOT: INTERNET OF THINGS WITH
PYTHON Lelio Campanile
lelio.campanile@gmail.com
@lelioc

HI THERE, I’M LELIO CAMPANILE
WORK AT UNICAMPANIA.IT
TEACHER AT APPLE FOUNDATION
COURSE FOR UNICAMPANIA.
Follow me: @lelioc
www.leliocampanile.it

WHAT IS MICROPYTHON?
Micropython is a lean and efﬁcient implementation of
Python 3 programming language.
Python on bare metal!
Open source project on github https://github.com/
micropython/micropython

FEATURES
▸ Support for many architectures
▸ Mostly compatible with normal python syntax
▸ Fit in 256Kb of code space and 16Kb of RAM
▸ Interactive prompt for easy development (REPL)
▸ Python hardware-speciﬁc modules

BECAUSE WE WANT
PROGRAMMING IN PYTHON
EVERYWHERE!!!

SUPPORTED BOARDS
▸ ESP 8266 (NodeMCU - SONOFF)
▸ PyBoard
▸ ESP32
▸ WiPy

MICROPYTHON ON ESP 8266 (NODEMCU)
ﬁrmware for ESP8266 from http://micropython.org/download#esp8266
You have here 4 kind of ﬁrmware:
- stable builds for device with 1024kb and above
- daily builds for device with 1024kb and above
- daily builds for device with 512kb
- work-in-progress OTA update Firmware

DEPLOYING THE FIRMWARE
▸ put your device in boot-loader mode
▸ put the ﬁrmware on device

DEPLOYING THE FIRMWARE/2
SIMPLY WAY WITH NODEMCU:
It has an usb connector with serial converter, it just works.
A LITTLE BIT TRICKY WAY:
But in other case you could need a usb to ttl converter (5v or
3,5 v) for example in sonoff you have to put GPIO0 to
ground-> on boot

WRITING TOOL FOR FIRMWARE
Now you need a writing tool
MicroPython supports esptool (https://github.com/espressif/
esptool/), a python-based, open source and platform
independent utility to write the ROM in ESP8266 and ESP32
chips:
pip install esptool

ERASE...
esptool.py --port /dev/cu.SLAB_USBtoUART erase_flash
esptool.py v2.3.1
Connecting........_
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Uploading stub...
Running stub...
Stub running...
Erasing flash (this may take a while)...
Chip erase completed successfully in 8.5s
Hard resetting via RTS pin...

...AND WRITE IT!
esptool.py --port /dev/cu.SLAB_USBtoUART --baud 460800
write_flash --flash_size=detect -fm dio 0 esp8266-20171101-
v1.9.3.bin
esptool.py v2.3.1
Connecting…….._
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 460800
Configuring flash size...
Auto-detected Flash size: 4MB
Flash params set to 0x0240
Compressed 600888 bytes to 392073…
Wrote 600888 bytes (392073 compressed) at 0x00000000 in 9.1 seconds (effective
527.6 kbit/s)...
Hash of data verified.
Leaving...
Hard resetting via RTS pin..

AT LAST!
REBOOT NODE MCU AND CONNECT TO IT VIA WIFI AP SSID: MICROPYTHON-XXXX AND PASSWD: micropythoN
Connect via serial and get REPL:
Read Evaluate Print Loop -> the easiest way to
test your code!
screen /dev/cu.SLAB_USBtoUART 115200

WEBREPL
EASIEST WAY TO TEST YOUR CODE OVER WIFI, WITH A BROWSER
LET'S ENABLE IT!
import webrepl_setup
FOLLOW THE ON-SCREEN INSTRUCTION.
NOW YOU ARE READY TO CONNECT TO MICROPYTHON VIA WEB REPL PROMPT.
HTTP://WWW.MICROPYTHON.ORG/WEBREPL/
HTTPS://GITHUB.COM/MICROPYTHON/WEBREPL FOR OFF-LINE USE AND FOR USE
COMMANDLINE TOOL, BASICALY TO COPY FILE IN YOUR DEVICE
python webrepl_cli.py boot.py 192.168.4.1:/boot.py

MAC OS X TIPS
Lists all usb device connected to your mac
ioreg -p IOUSB -w0
+-o Root <class IORegistryEntry, id 0x100000100, retain 15>
+-o AppleUSBXHCI Root Hub Simulation@14000000 <class
AppleUSBRootHubDevice, id 0x1000003f8, registered, matched,
active, busy 0 (1 ms), retain 10>
+-o iBridge@14200000 <class AppleUSBDevice, id
0x1000003fa, registered, matched, active, busy 0 (50 ms),
retain 36>
+-o CP2102 USB to UART Bridge Controller@14600000 <class
AppleUSBDevice, id 0x100002114, registered, matched, active,
busy 0 (68 ms), retain 11>
when I plugin the node mcu in my mac I view this new usb
device, but it don't load the right usb-serial driver…

INSTALL USB-SERIAL DRIVER
install CP210x USB to UART Bridge VCP Drivers for
nodemcu serial adapter built-in from:
https://www.silabs.com/products/development-tools/
software/usb-to-uart-bridge-vcp-drivers
after a reboot of your mac you could able to view /dev/
cu.SLAB_USBtoUART
LAST TIP:
make sure to try out different USB cables as well!

SETTING NETWORK INTERFACE
>>> import network  
>>> client = network.WLAN(network.STA_IF)  
>>> ap = network.WLAN(network.AP_IF)  
>>> client.active()  
False  
>>> ap.active()  
True  
>>> client.active(True)  
#5 ets_task(4020ed88, 28, 3fffabe8, 10)  
>>> client.connect('Daddelio Network', '********')  
>>> client.ifconﬁg()  
('192.168.1.87', '255.255.255.0', '192.168.1.1', '192.168.1.1')

INTERNAL FILESYSTEM
# internal filesystem
>>> import os
>>> os.listdir()
['boot.py', 'webrepl_cfg.py']
>>>
the boot.py is executed when device boot up. Insert in
boot.py the code that you want to execute when the board
start up.
After boot.py your board runs main.py.

MEET THE EXTERNAL WORLD: GPIO BASICS
# GPIO basics
>>> import machine
>>> led = machine.Pin(2, machine.Pin.OUT)
>>> led.value()
>>> 0
>>> led.on()
>>> led.off()

BLINK BUILT IN LED
# blinking led
>>> import time
>>> for i in range(10):
... led.on()
... time.sleep(0.5)
... led.off()
... time.sleep(0.5)
...

BREATHING LED
# breathing led
>>> import machine
>>> import time
>>> pwm_led = machine.PWM(machine.Pin(2))
>>> pwm_led.duty(1023)
>>> for i in range(3):
... for up in range(1023, -1, -50):
... pwm_led.duty(up)
... time.sleep(0.05)
... time.sleep(0.5)
... for down in range(0, 1023, 50):
... pwm_led.duty(down)
... time.sleep(0.05)
... time.sleep(0.5)
...

GPIO IN: BUTTON TURN ON LED
# button turn on led
>>> button = machine.Pin(14, machine.Pin.IN,
machine.Pin.PULL_UP)
>>> while True:
... if not button.value():
... led.value(not led.value())
... time.sleep(0.4)
... while not button.value():
... pass

TEMPERATURE AND HUMIDITY
z
# DHT 11 temperature
>>> import machine
>>> import dht
>>> dht_sensor = dht.DHT11(machine.Pin(2))
>>> dht_sensor.measure()
>>> dht_sensor.temperature()
>>> 22
>>> dht_sensor.humidity()
>>> 64

HOME AUTOMATION: HOME
ASSISTANT

INSTALL IT !
You need python3, then:
mkdir homeassistant
cd homeassistant
python3 -m venv .
source bin/activate
pip3 install wheel
pip3 install homeassistant

RUN HOME ASSISTANT
hass
and voilà http://127.0.0.1:8123

CONFIGURE HOME ASSISTANT
It is simple!!
you can configure mostly write one file:
~/.homeassistant/configuration.yaml
And now home assistant tries to discover supported
components on startup with no configuration!

CONFIGURE NETATMO
netatmo:
api_key: YOUR_CLIENT_ID
secret_key: YOUR_CLIENT_SECRET
username: YOUR_USERNAME
password: YOUR_PASSWORD

MQTT: MQ TELEMETRY TRANSPORT
IT IS A SIMPLE LIGHTWEIGHT MESSAGING
PROTOCOL, IT WORKS WITH LOW-BANDWITDH AND
LOW RESOURCE ENVIROMENTS.
IT IS PERFECT FOR IOT!

MQTT BASIC CONCEPTS
▸ Publish - Subscribe
▸ Messages
▸ Topics
▸ Broker

PUBLISH-SUBSCRIBE
A device can publish messages on a topic
A device can be subscibed on a topic and receive the
message

TOPICS AND MESSSAGES
Topics are a kind of channels
Topics are strings separate by slash "/"
For example :
home/living/lamp
for example you could send (publish) a message on topic
"home/living/lamp" to turn on the lamp in your living room.
The lamp receives this message because subscriber of that
topic.
A message is the information sent, it is a simple command or
data

BROKER
Broker is responsible to receive all messages, ﬁltering and
route their to subscribed clients
Home assistant has an embedded MQTT Broker: hbmqtt, a
python mqtt broker
It exists many other MQTT Broker, for example:
Mosquitto broker - http://mosquitto.org)

WHAT IS MY
GOAL?
NODEMCU WITH DHT11 THAT COMMUNICATE TO
HOMEASSISTANT VIA MQTT PROTOCOL:
FULL STACK PYTHON FOR IOT

MICROPYTHON SIDE
import machine
import time
import dht
from umqtt.simple import MQTTClient
broker = "192.168.1.65"
topic = "home"
client_id = "nodemcu_" + machine.unique_id()
def main():
client = MQTTClient(client_it, broker)
client.connect()
while True:
dht_sensor.measure()
temp_data = dht_sensor.temperature()
client.publish(topic+'/'+client_id, bytes(str(temp_data),
'utf-8'))
time.sleep(60)
if __name__ == '__main__':
main()

HOME ASSISTANT SIDE
In configuration.yaml:
sensor:
- platform: mqtt
state_topic: "home/nodemcu_****unique_id****"
name: "nodemcu_temp"

IoT: Internet of Things with Python

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