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      8-Channel relay controller with keypad and RS485 interface (2)

      pubsub.slavino.sk / onetransistor · Saturday, 10 December, 2022 - 16:15 edit · 1 minute

    In the previous post I built a front panel with 8 push buttons which will be used to activate a module of 8 relays. Having so many I/O lines I had to come with a solution to be able to read and set each one of them with common microcontrollers. I ended up using 74HC165 for inputs and 74HC595 for outputs. These ICs are shift registers controlled using a serial synchronous protocol similar to SPI.

    In this post you will see the entire outdoor unit. In the end there will be two units, the outdoor one with keypad and relays; the other is the indoor unit with Wi-Fi connectivity and MQTT capabilities. A keypad will be featured on this one too. I went with this approach because I want a robust implementation without Wi-Fi dependency. Nevertheless the keypad on outdoor unit can be remotely disabled to prevent unauthorized use. I decided to use two units after a failed design which implied the use of an ESP8266 board directly as the MCU of outdoor unit. I had problems with voltage levels (shift registers are both 3.3 V and 5 V compatible, however my relay board is 5 V only, while ESP8266 is 3.3 V only; besides that, 3.3 V applied to shift registers powered from 5 V is not recognized as digital HIGH).

    Relay controller inside plastic box
    Relay controller inside plastic box

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    Visit One Transistor .

    Značky: #Elektro, #RS485, #PCB, #74HC595, #Arduino, #3D-Print, #74HC165

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      Exporting your HTML table to CSV

      pubsub.slavino.sk / arduinodiy · Saturday, 1 October, 2022 - 13:46 edit

    The WebApp showing the measuring points in the Firebase database database that I presented in a previous article and which was in fact built on a project by randomnerdtutorials, includes a table of the collected datapoints that can be shown, hidden and also deleted. Printing (just roughly)In case you want to keep this data, there … Continue reading "Exporting your HTML table to CSV"

    Značky: #Arduino, #Elektro

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      Front panel for 8-channel relay controller (1)

      pubsub.slavino.sk / onetransistor · Saturday, 24 September, 2022 - 20:10 edit

    This project started from a common issue I faced while trying to interface a relay board with a microcontroller: not enough I/O pins. My purpose is to control 8 outdoor lights; therefore, I got an 8-channel relay board, powered from 5 V. But I want to add some extra functionality: this controller should have a front panel with 8 push buttons and 8 LEDs. It should also take input from sensors with digital output. So, I got 16 inputs and 16 outputs to control.

    The most available solution was to use shift registers, 74HC595 for outputs and 74HC165 for inputs. Initially I thought I could use an ESP8266 microcontroller, since it would allow me to add MQTT functionality. But I had no success with this: ESP8266 is a 3.3 V microcontroller, relay board needs 5 V levels, and although shift registers can operate properly with voltages as low as 2 V, they will not recognize as high (“1”) a voltage of 3.3 V (from ESP8266) when powered with 5 V. The reason I powered them with 5 V is because relays will not be activated by 3.3 V.

    Front panel fitted on the plastic cover of a wiring box
    Front panel fitted on the plastic cover of a wiring box

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    Visit One Transistor .

    Značky: #3D-Print, #74HC595, #Arduino, #PCB, #Elektro, #74HC165

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      Firebase datalogging from Anywhere

      pubsub.slavino.sk / arduinodiy · Saturday, 24 September, 2022 - 19:39 edit

    Recently, Randomnerdtutorials published a string of articles on using Firebase to control or monitor your ESP8266 or ESP32 from basically anywhere in the world. These articles are very very worthwhile reading as they describe in detail making a Firebase hosted WebApp that allows you to do the above mentioned control. (another good resource is on … Continue reading "Firebase datalogging from Anywhere"

    Značky: #Arduino, #Elektro

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      ESP8266 and MySQL with Grafana

      pubsub.slavino.sk / arduinodiy · Saturday, 9 July, 2022 - 11:18 edit

    In a previous article I described how to use InfluxDB to collect data from an ESP8266 and present that in Grafana or Chronograf. Grafana can also be used to present data that has been collected in a MySQL or MariaDB database. If you want your data as a graph, make sure that the data is … Continue reading "ESP8266 and MySQL with Grafana"

    Značky: #mysql, #Arduino, #Elektro, #grafana, #ESP8266

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      ESP8266 with influxDB and Grafana

      pubsub.slavino.sk / arduinodiy · Saturday, 21 May, 2022 - 22:47 edit

    In an earlier post I referred to the use of InfluxDB and Grafana to store and present data. In this post I will explain how to do this.There is a recent post of randomnerdtutorials on Influxdb as well, but where Rudy and Sarah discuss the use of a Cloud server, I will be using a … Continue reading "ESP8266 with influxDB and Grafana"

    Značky: #ESP8266, #Arduino, #influxdb, #Elektro, #grafana

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      Simple webserver for SonOff basic

      pubsub.slavino.sk / arduinodiy · Monday, 25 April, 2022 - 12:20 edit

    Sure there is Tasmota and ESPhome or ESPEasy, but here is a simple webserver that controls the relay, the Green LED and also the Red LED.On the WiFi version of the SonOff Basic, the Red LED is not connected (it is for the 433Mhz version), but it can be easily utilized by soldering a wire … Continue reading "Simple webserver for SonOff basic"

    Značky: #Elektro, #Arduino

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      Real time graph for data logging

      pubsub.slavino.sk / arduinodiy · Wednesday, 6 April, 2022 - 08:21 edit

    While scowering the internet for some hardware info on data logging i came upon a logging program that seemed interesting at first, but that kept crashing my ESP8266 the moment the webpage was loaded. But as i like a challenge, I set out to find the fault and fix it. In the end it involved … Continue reading "Real time graph for data logging"

    Značky: #Elektro, #Arduino

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      Coldframe monitoring with an ESP8266 (2)

      pubsub.slavino.sk / arduinodiy · Tuesday, 15 February, 2022 - 07:55 edit

    In an earlier post, I described a Coldframe that was being monitored by an ESP8266. Though I was quite happy with the result, I did learn a few things that I would do different with a new ColdFrame, which I now have built.I made the following changes:I ditched the HTU21D sensor as I found it … Continue reading "Coldframe monitoring with an ESP8266 (2)"

    Značky: #Arduino, #Elektro