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This guide will show you how to connect (WiFi) devices in the OpenDevice server and send data to save in storage and further visualization in dashboards, all in real time. server to store and then use this data to perform analysis using the dashboards.
We will use the DHT22 sensor connected to the WiFi ESP8266 module to collect temperature and humidity, and send the server using the MQTT protocol.
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- OpenDevice server up and running (guide)
- Arduino IDE (with required OpenDevice Libraries)
- ESP8266 module (like NodeMCU)
- DHT22 sensor DHT22/DHT11 sensor (and Adafruit's DHT22 library)
DHT22 |
NodeMCU |
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Wiring
The most basic DHT humidity and temperature sensor comes in two variants with different levels of accuracy.
| DHT-11 | DHT-22 | |
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| Humidity range | 20%-80%RH (±5%RH) | 0%-100%RH (±2%RH) |
| Temperature range | 0-50°C (±2°C) | -40-80°C (±0.5°C) |
| Measurement time | 1s per sample | 2s per sample |
Setup
To program the NodeMCU, we are going to use Arduino's IDE. It's the easiest way to get up and running with the DHT22.
First, you'll have to set up your machine : (Device Setup Instructions). These instructions take you through installing the IDE, ESP8266 and the proper required libraries.
In addition to this, you'll have to install DHT sensor library to read the sensor, we are going to use Adafruit's DHT22 library., and Adafruit Unified Sensor Driver
Install Adafruit's DHT22 library using Library Manager:
Next, install Adafruit Unified Sensor Driver
Code / Firmware
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Next we need to configure the device name (you choose) and the api key (see this guide).
App Code (full example)
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You do not have to do much, just make sure you are looking at the console, if the WiFi connection and the server MQTT was successfully performed.
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Start the OpenDevice (guide), access (http://localhost:8181), and verify that your devices have been registered correctly.
In the Boards page, you should see your device/module already.:
Our module has two linked devices:
On this page we already have a series of tools and visualizations that we can analyze how the device is behaving.
But we have a better tool to do the analyzes that are the Dashboards
Create custom visualizations using Dashboards
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You can also add more then on device on the chart:
You have the freedom to edit and position and enlarge the graph as you wish
Let's now add a gauge that shows the temperature value in real time:
You have the freedom to edit and position and enlarge the graph as you wish
After organizing our charts, dragging and expanding, we get the result:
Update firmware over WiFi (OTA)
Now after the device is working and online, we can upgrade via OTA. In the Arduino IDE, the device should appear as if it were a Port:
WHAT'S NEXT?
At this point, you are collecting and visualizing data. But, what about reacting to it? The next step is to build a Rule(/wiki/spaces/DOC/pages/99352732) in Losant to send yourself a text message whenever the humidity gets too highlow.
See examples:
https://github.com/OpenDevice/opendevice-lib-arduino/tree/master/examples
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