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Ina226 voltage and current sensor with esp8266 sending by MQTT

I needed to measure the voltage and the current of my lawn mower robot, as i have already an home automation system, the point was also to integrate these measures into Openhab and idealy using mqtt protocol. The first idea that came up was to use a voltage divider to measure the voltage with the esp8266 analog pin.Nevertheless i found some contradictives infos about this, the accepted voltage was low between 1v and 2v depending on the sources. Unfortunately my battery is a 28,4v one.
With some search I found on banggood the ina226 sensor already soldered and ready to plug with an arduino. The question was; is this compatible with an esp8266 to allow an easy integration with my home automation system.
The answer is yes.

Thanks to the help of Shelvin blog here are the details:

Pinout for a NODEMCU: Nodemcu/INA226 D1/SCL D2/SDA GND/GND 5V/VCC
IN+ & IN- correspond to the current meter for the tests, I linked them before the INA226 power so as to have some current measurements. VBS is for volta…

Feedback about room temperature sensor with standalone ATMEGA328P and DHT22

After some months of low cost low power room sensor usage here is the feedback.

The sensor send every hour to OpenHAB with the OpenMQTTGateway temperature, voltage and humidity data, it is powered by 3 AA alkaline batteries.

But the most interesting thing about this sensor is how the battery voltage decrease so as to have an idea on the batteries lifetime.

Here is below voltage (mV) graph on the last day, month and 4 months sent by the sensor (the charts are updated every day):

4 months

We can see that on a 4 months duration the battery decreased around 0,1V. If we consider an end of life at 3V for our 3 AA batteries this give us a lifetime of  4,5V - 3V = 1,5V 15 * 4 months = 60months = 5 years of expected duration (without taking into account the AA auto discharge)
5 years of expected duration with a less than 8€ sensor !

Major version of 433toMQTTto433 gateway --> OpenMQTTGateway

A new version of the gateway is available on github:

This version introduce the following changes:

esp8266 and arduino compatibility with the same codecode SRAM load optimization for arduino unogroup user and other parametersremove duplicate for IRRF protocols definition in subjectRF pulse length definition in subjectacknowledgement inside a subtopiccode refactoringhandle MQTT authentication automaticaly if user setput parameters on an user_config.h file

Major change is the arduino and esp8266 compatibility with the same code, the goal is to be able to maintain the gateway for both platform on a more easy way.

You will notice also that the code has been optimized and the sram footprint also.

It is now possible to define into the topic some rcswitch parameters like protocol and pulselength.

I add some requests about adding direct modules like DHT sensor or fan on the gateway but wouldn't like to drift the code from what it is first ... a gat…

Making your RF 433mhz sensors and devices communicate with your home automation, gateways comparison

After more than one year of usage of home automation (HA) I have seen that one critical point is the communication between the sensors/devices and the HA system. 

There is several possibilities for that:
Infrared5,8ghz2,4ghz867mhz433mhzwire...And for each of these possibility we can have a huge amount of different protocols. The goal of this article is to draft a list of the 433mhz gateways that can be found. We will focus on 433mhz due to the fact that in european countries 433mhz devices/sensors are quite easy to find and with a correct price.
We will take the following citerias: PriceDIY complexityNumber of protocols taken into accountComplexity of home automation integrationAnd take a look at RFXCom, RFLink, 433toMQTTto433 ESP8266, 433Utils, Broadlink RM... I will put in green the keypoints of each gateway.
E&R = 433mhz emitter and receiver, can be a FS1000A and a XD-RF-5V or a superheterodyne one (recommended)

Low cost low power room sensor with atmega328p and 433mhz transmission

Following my first build of an external garden sensor, here is a simplified version with temperature, humidity and battery voltage measurement for a baby bedroom

[EDIT] feedback about the expected battery duration here

The requirements are:
cheaplong battery life, the atmega328p run at 8mhz with minimal components and functionsunder 8€wireless (433Mhz) with good range (2 walls to cross and 10 meters)Here is the final view attached to a lion for decoration:

And a report from OpenHab displaying the sensor data:

If you want more details about energy power consumption the first article on this subject is more detailled.

Now let's see how to build this.
Bill of materialThe sensors is based on atmega328p(3€),  a 433 Mhz transmitter (1,5€) ,a DHT22 temperature and humidity sensor (4€),a 433 mhz antenna (0,18€)DIP socket adaptor for the ATmega (1€)an electronic prototype printed circuit board (0,5€)At total we are around 8€
PrincipleEvery hour the sensor send the data to a 433Mhz gateway so as to …

Infrared IR, 433mhz and MQTT on ESP8266 bidirectional gateway 433nIRtoMQTTto433nIR

Following discussions on the home assistant forum people gave me the idea to add Infrared communication to the 433mhz gateway. 

The goal is to act as a gateway between 433Mhz sensors, infrared remote controls and a MQTT broker or between the MQTT broker and 433Mhz actuators, infrared devices, It enables to:
receive MQTT data from a topic and send RF 433Mhz signal corresponding to the received MQTT data publish MQTT data to a different topic related to received 433Mhz signal receive MQTT data from a topic and send infrared signal corresponding to the received MQTT data publish MQTT data to a different topic related to received infrared signal 
It can be an interesting part in an home automation system so as to interface sensors and actuators (wall sockets), your tv, home cinema, hifi ... with software like openhab or home assistant.

List of compatible RF sensors here

[EDIT] all infos are now centralized into the github repository take a look at it you will find up to date info about OpenMQT…

Interfacing the 433mhz bidirectional MQTT Gateway with Openhab

In this article I’m going to detail how to integrate the OpenMQTTGateway with OpenHAB using MQTT protocol.
We will explore two kind of integration : -a cheap socket wall switch (on/off) -a voltage sensor ( values between 0 to 5000mV) based on this tutorial
Before continuing you must have :·An MQTT broker running (for example mosquitto) ·An OpenHAB instance running with the MQTT addon binding configured to talk to your MQTT broker ·The 433mhz Gateway setup (either arduino or esp8266 one)
Cheap wall socketThe wall socket that we will be using are these ones
Be carefull not all the wall sockets are compatible with RCSwitch (Library used by the 433Mhz Gateway). For example blyss ones are not compatible.
Learning the codes of your plugFirst step will be to learn the code that are used by the plug. So as to that open your command line and subscribe to the following subject : home/433toMQTT Press the ON button of the remote control of your plug You should see a value on the command line (example 678720)…