mirror of
https://github.com/home-assistant/home-assistant.io.git
synced 2025-05-08 20:18:59 +00:00
107 lines
4.0 KiB
Markdown
107 lines
4.0 KiB
Markdown
---
|
|
layout: post
|
|
title: "ESP8266 and MicroPython - Part 2"
|
|
description: "Using MicroPython and MQTT on ESP8266 based devices and Home Assistant."
|
|
date: 2016-08-31 06:17:25 +0200
|
|
date_formatted: "August 31, 2016"
|
|
author: Fabian Affolter
|
|
comments: true
|
|
categories: How-To MQTT ESP8266 Micropython
|
|
og_image: /images/blog/2016-07-micropython/social.png
|
|
---
|
|
|
|
<img src='/images/blog/2016-07-micropython/micropython.png' style='clear: right; border:none; box-shadow: none; float: right; margin-bottom: 12px;' width='200' />
|
|
So, part 1 of [ESP8266 and MicroPython](/blog/2016/07/28/esp8266-and-micropython-part1/) was pretty lame, right? Instead of getting information out of Home Assistant we are going a step forward and create our own sensor which is sending details about its state to a Home Assistant instance.
|
|
|
|
<!--more-->
|
|
|
|
Beside [HTTP POST](https://en.wikipedia.org/wiki/POST_(HTTP)) requests, MQTT is the quickest way (from the author's point of view) to publish information with DIY devices.
|
|
|
|
You have to make a decision: Do you want to pull or to poll? For slowly changing values like temperature it's perfectly fine to wait a couple of seconds to retrieve the value. If it's a motion detector the state change should be available instantly. This means the sensor must take initiative.
|
|
|
|
An example for pulling is [aREST](/components/sensor.arest/). This is a great way to work with the ESP8266 based units and the Ardunio IDE.
|
|
|
|
### {% linkable_title MQTT %}
|
|
|
|
You can find a simple examples for publishing and subscribing with MQTT in the [MicroPython](https://github.com/micropython/micropython-lib) library overview in the section for [umqtt](https://github.com/micropython/micropython-lib/tree/master/umqtt.simple).
|
|
|
|
The example below is adopted from the work of [@davea](https://github.com/davea) as we don't want to re-invent the wheel. The configuration feature is crafty and simplyfies the code with the usage of a file called `/config.json` which stores the configuration details. The ESP8266 device will send the value of a pin every 5 seconds.
|
|
|
|
|
|
```python
|
|
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](/components/sensor.mqtt/) to check if the sensor values are published.
|
|
|
|
```bash
|
|
$ mosquitto_sub -h 192.168.1.19 -v -t "home/#"
|
|
```
|
|
|
|
```yaml
|
|
sensor:
|
|
- platform: mqtt
|
|
state_topic: "home/esp8266_[last part of the MAC address]"
|
|
name: "MicroPython"
|
|
```
|
|
|
|
[@davea](https://github.com/davea) created [sonoff-mqtt](https://github.com/davea/sonoff-mqtt). This code will work on ESP8622 based devices too and shows how to use a button to control a relay.
|
|
|