Tag • #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

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

Značky: #Arduino, #Elektro

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Conditional images in a webpage

pubsub.slavino.sk / arduinodiy · Monday, 19 September, 2022 - 09:35 edit

Sometimes in a web application you want different pictures to appear, depending on a condition. For many die hard programmers that will be a piece of cake, but for may others it isn’t. Suppose you have an application that monitors if the level in your water tank is full or not completely full yet (say … Continue reading

Značky: #Uncategorized, #Elektro, #HTML

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ESP8266 web server is slow to close connections

pubsub.slavino.sk / avian_blog · Sunday, 14 August, 2022 - 14:48

ESP8266WebServer waits 2 seconds before closing a HTTP/1.0 connection when it should close it immediately.

Značky: #Code, #Elektro

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Saving power on an ESP8266 web server using delays

pubsub.slavino.sk / avian_blog · Saturday, 13 August, 2022 - 15:19

Adding a small delay to loop() can save 60% of power consumption on an ESP8266 running the ESP8266WebServer library.

Značky: #Digital, #Elektro

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Turnkey PCB Assembly by PCBGOGO - 2022 Q3

pubsub.slavino.sk / onetransistor · Sunday, 31 July, 2022 - 14:08 edit

Modern electronic devices can only work properly if the printed circuit boards (PCBs) they are built on are reliably manufactured with high precision. PCBGOGO manufactures the best PCBs and they can meet specific client needs. It is one of the world's leading PCB manufacturers, with a production line that can provide both precision and reliability. PCBGOGO provides turnkey assembly for their customers so you can use the PCB as soon as it is delivered to you. They provide quick, professional, and reliable turnkey PCB assembly.

Turnkey PCB Assembly by PCBGOGO - 2022 Q3