ESP32 with multiple DS18B20 temperature sensors

Guide to ESP32 with multiple DS18B20 temperature sensors from Random Nerd Tutorials: This guide shows how to read temperature from multiple DS18B20 temperature sensors with the ESP32 using Arduino IDE. We’ll show you how to wire the sensors on the same data bus to the ESP32, install the needed libraries, and a sketch example you can […]

EEPROM rotation for ESP8266 and ESP32

Xose Pérez over at Tinkerman writes: The Arduino Core for ESP8266 and ESP32 uses one SPI flash memory sector to emulate an EEPROM. When you initialize the EEPROM object (calling begin) it reads the contents of the sector into a memory buffer. Reading a writing is done over that in-memory buffer. Whenever you call commit […]

Video tutorials: Building the Arduino based data loggers

From the comments on our Arduino data logger post: A visiting researcher dropped by our humble basement workshop with questions about the physical skill level students would need if they added one of our DIY data loggers to their environmental curriculum. I figured the easiest way to cover that was to simply build one, while they […]

Tutorial: Setting up a low cost QRP (FT8, JT9, WSPR etc) monitoring station with an RTL-SDR v3 and Raspberry pi 3

A detailed tutorial on how to set up a cheap QRP monitoring station using an RTL-SDR V3 and a Raspberry Pi 3 from rtl-sdr.com This tutorial is inspired by dg0opk’s videos and blog post on monitoring QRP with single board computers. We’ll show you how to set up a super cheap QRP monitoring station using an […]

5 LDO regulator considerations other than voltage and current

James Lewis over at Bald Engineer writes, “For an AddOhms series, I created a DIY Arduino I am calling the “Pyramiduino.” It is an ATmega328p based board in the shape of a triangle. Other than being cute, the shape does not offer any other benefit. The design features a 3.3 volt LDO Regulator, which is […]

Arduino time attendance system with RFID

A how-to on building a time attendance system with MFRC522 RFID Reader and Arduino from Random Nerd Tutorials: Before getting started it’s important to layout the project main features: *It contains an RFID reader that reads RFID tags; *Our setup has a real time clock module to keep track of time; *When the RFID reader reads an […]

How servo motors work and how to control servos using Arduino

Dejan Nedelkovski over at HowToMechatronics shared detailed tutorial on how servo motors work and how to control servos using Arduino and PCA9685 PWM driver: There are many types of servo motors and their main feature is the ability to precisely control the position of their shaft. A servo motor is a closed-loop system that uses […]

Why electrolytic capacitors are actually kinda shitty

Afroman writes, “Electrolytic capacitors are common, but knowledge of their limitations is uncommon. A demonstration is shown highlighting the difference in performance between electrolytic and ceramic capacitors in power supplies. Other topics discussed in the video: Electrolytic capacitor construction, ceramic capacitors, ESR, ESL, impedance curves, why “0.1uF”, and more.” Via Afrotechmods. Check out the video after […]

Alexa (Echo) with ESP32 and ESP8266 – Voice controlled relay

Rui Santos writes, “In this project, you’re going to learn how to control the ESP8266 or the ESP32 with voice commands using Alexa (Amazon Echo Dot). As an example, we’ll control two 12V lamps connected to a relay module. We’ll also add two 433 MHz RF wall panel switches to physically control the lamps.” More […]

Debug SONOFF AC relay with a thermal camera

James Lewis shares his experience in debugging SONOFF AC relay with a thermal camera: The clever solution seemed to be clever, at least for a few minutes. Suddenly the light turned off. I thought maybe there was a timeout for the manual button. Annoying, but workable. The lamp remained off for about another 2 minutes when […]

ESP8266 Wi-Fi button – DIY Amazon dash button clone

Rui Santos over at Random Nerd Tutorials posted a step by step guide on building an ESP8266 Wi-Fi button: In this project you’re going to build an ESP8266 Wi-Fi Button that can trigger any home automation event. This is like a remote control that you can take in your pocket or place anywhere that when […]

Arduino Tutorial: Adding sensors to your data logger

Edward Mallon writes: This post isn’t another How-To tutorial for a specific sensor because the Arduino community has already produced a considerable number of resources like that.  You’d be hard pressed to find any sensor in the DIY market that doesn’t give you a dozen cookbook recipes to follow after a simple Google search. In […]

Pulse Oximeter functionality for a medical device

Alexander Lang writes: The gentlemen for whom I’m developing this hardware for has requested some additional functionality. The additional functionality requested is a Pulse Oximetry measurement.  Pulse Oximetry is the measurement of a person’s pulse along with how much oxygen is present within their blood.  It is a common measurement made by medical practitioners to […]