Posts in Electronics
Smartphone Arduino Weighing Scale with Load Cell and HX711

In this tutorial, I introduce an Arduino-based weighing scale that uses a load cell, analog-to-digital converter, and calibrated mass. I introduce calibration with known masses to create a powerful and accurate weighing system that can be used for highly accurate measurement purpose such as: chemistry, horticulture, cooking, and much more!

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Arduino Weighing Scale with Load Cell and HX711

In this tutorial, I introduce an Arduino-based weighing scale that uses a load cell, analog-to-digital converter, and calibrated mass. I introduce calibration with known masses to create a powerful and accurate weighing system that can be used for highly accurate measurement purpose such as: chemistry, horticulture, cooking, and much more!

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Image Processing with Raspberry Pi and Python

The Raspberry Pi has a dedicated camera input port that allows users to record HD video and high-resolution photos. Using Python and specific libraries written for the Pi, users can create tools that take photos and video, and analyze them in real-time or save them for later processing. In this tutorial, I will use the 5MP picamera v1.3 to take photos and analyze them with Python and an Pi Zero W. This creates a self-contained system that could work as an item identification tool, security system, or other image processing application. The goal is to establish the basics of recording video and images onto the Pi, and using Python and statistics to analyze those images.

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Arduino SD Card Module Data Logger

This tutorial will explore the range of capabilities available to the Arduino SD library by using a real-world example of data logging. The SD library allows users to read/write, list files, create/remove files, and make/delete directories. Additionally, we will develop an algorithm that creates a new file every time the Arduino board is restarted, which will prevent overwriting of existing data records. The resulting data file will be in comma separated format and contain multiple data points, including a time stamp in milliseconds since the program started. Therefore, it is important to record the program start time. For very accurate time monitoring tasks, a real-time clock is recommended, however, for the experiments conducted here, relative time suffices.

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Importance of Silkscreens for PCB Identification and Labeling

Just as the signal lights of your car help to indicate when your car plans to take a turn or change lanes, the silkscreen is also used in the PCB process to help in testing and troubleshooting the board. The layer of silkscreen contains information regarding the PCB assembly process. This includes the location of components, their polarity and details for their placement and orientation, identifiers, labels and logos for various components. Your silkscreen must have a clear and readable font. In order to explain why silkscreen is so crucial let us discuss its importance in assembly and testing of PCBs.

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Arduino Uno R3 vs CH340

The CH340 Arduino board contains an ATmega328P-U-TH chip, which differs from the classic ATmega328P-PU in official Arduino Uno Rev3 boards. The CH340 is an inexpensive USB-to-Serial chip (datasheet here) that takes the place of the Rev3 board’s more expensive ATmega16U2. This creates issues when programming the Arduino board with certain operating systems (specifically Windows), however, for most Linux and Mac systems - there appears to be no issue. In this tutorial, I will explore the CH340 Arduino board to see whether there are differences in performance and power under different operating conditions. This will definitively answer whether the CH340 is a worthy alternative to the Rev3 or if it’s just a cheap imposter.

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Controlling LEDs with A Multiplexer and Arduino

A demultiplexer will be used to control 8 LEDs using just 3 digital pins on the Arduino board. This method of demultiplexing frees up pins on the Arduino, but also makes control of multiple LEDs easier by consolidating the power given to each LED. This will allow us to use LEDs without resistors. In general, a demultiplexer uses N boolean outputs to control 2N switches. In our case, the CD4051 multiplexer will be used as a demultiplexer using 3 digital pins and boolean logic to control 8 individual LEDs. Several skills will also be developed, specifically with regard to programming in the Arduino programming language. Pulse-width modulation (or brightening and dimming) of LEDs will be explored, as well as randomization of LED blinks, along with the general selection process for boolean switching with the demultiplexer.

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Loudspeaker Analysis and Experiments: Part II

Part II of the tutorial series on loudspeaker analysis and experiments. The majority of this entry focuses on finding Thiele-Small parameters to fully characterize an electrodynamic loudspeaker in free air.

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Loudspeaker Analysis and Experiments: Part I

In this tutorial, a loudspeaker will be analyzed by calculating the Thiele-Small parameters from impedance measurements using an inexpensive USB data acquisition system (minimum sampling rate of 44.1 kHz). The methods used in this project will educate the user on multiple engineering topics ranging from: data acquisition, electronics, acoustics, signal processing, and computer programming.

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NodeMCU Tutorial Series Part II: NodeMCU Server Control Over Local Area Network

This tutorial takes full advantage of the ESP8266 WiFi chip by serving a local webpage to control the general purpose input and output (GPIO) pins on a NodeMCU microcontroller. Some basic HTML and CSS programming methods will be utilized to create a stylish webpage that is both asynchronous (AJAX) and input-driven - this will give the user the ability to control the pins on the microcontroller. For the current example, an electromagnet and LED will be controlled using pulse width modulation (PWM) and simple high/low logic, respectively. The PWM control allows the user to change the voltage to the component, altering the magnetic field of the electromagnet. For the LED, the traditional digitalWrite() method will turn the LED on and off.

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NodeMCU Tutorial Series Part I: Arduino IDE and Blinking an LED

NodeMCU is a WiFi platform that integrates the ESP8266 system on chip hardware with the familiarities of open-source software. The NodeMCU is powerful because it endows users with the ability to create Internet of Things (IoT) projects at a relatively low cost with tools readily available and open to the maker community. NodeMCU is fully compatible with the Arduino IDE, which is the method for programming the board in this tutorial.

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Internet of Things WiFi and Bluetooth Mesh Network with Particle Argon and Xenon Boards

In the tutorial, the simplest integrated IoT mesh network is explored, where Argon (WiFi + BLE) and Xenon (BLE) Particle boards are used to create an ultrasonic range detector (HC-SR04) that notifies an LED whether a threshold value has been crossed in front of the sensor. When the threshold is reached, a ‘trip’ is communicated to the mesh network and notifies the system via Bluetooth and WiFi.

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iPhone Datalogger with Arduino Using The iOS Bluetooth App BLExAR

The BLExAR app will be used in conjunction with a CC2541 (HM-10, JDY-08, AT-09, SH-M08) Bluetooth module and an Arduino (ATmega328) board to create a simple data acquisition system. A DHT22 sensor will provide temperature and humidity data to the Arduino which will be recorded by an iOS device via the BLExAR app. This experiment is a real-world example of an Arduino application demonstrating data acquisition from a real sensor. This tutorial will allow users to solve their own engineering problems using the modern Arduino platform and wireless communication through the BLExAr app, which will ultimately expand the reach and compatibility of technology in the classical sciences through exploration and experimentation.

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4-Pin RGB LED Control Using iOS BLExAR App, HM-10 Bluetooth Module, and Arduino

Control an RGB LED using three PWM pins on an Arduino Uno board via Bluetooth communication. An RGB LED is a single casing with three cathode (or anode) pins and one anode (or cathode) pin. This results in a 4-pin LED. In this tutorial, I will be using an RGB LED with three anodes and one common cathode. This means that we can change the color of the LED to over 16.7 million different variations (assuming each anode produces a different luminosity for each voltage change of the Arduino PWM pin). This tutorial will help demonstrate the power of the BLExAR app, and the flexibility of an Arduino board under iOS Bluetooth control. In my case, I will be using an iPhone with the BLExAR app, but an iPad would suffice as well.

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iOS and Arduino Bluetooth Communication Using The BLExAR App and CC2541 Module

An app called “BLExAR” allows Arduino users to communicate to an iOS device (iPhone or iPad) using a Bluetooth CC2541 module (different versions are called: HM-10, SH-M08, AT-09, or JDY-08). The app permits control of an Arduino board, wireless serial communication, and data acquisition. Click on the app logo shown here to download the app, as it will be used as the iOS communication software. On the Arduino side, we need to wire the CC2541 Bluetooth Low Energy (BLE) module to an Arduino board and upload the appropriate software via the Arduino IDE. In this tutorial, we will demonstrate how to verify communication between an Arduino and CC2541 Bluetooth module, and then use Bluetooth communication to send strings between an iOS device and the Arduino ATmega328p board.

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Arduino SoftPot LED Meter (Membrane Potentiometer)

How to use a soft, circular-membrane potentiometer with an Arduino board. Potentiometers function by altering the voltage of a system by mechanically changing the resistance associated with a voltage divider. In a traditional potentiometer (think of turning a volume knob), we are physically changing the voltage of a system. In the case of a soft potentiometer (where the name SoftPot comes from), we are altering the resistance of the voltage divider by physically depressing the potentiometer, thereby changing the resistance at a contact point. The working principle is exactly the same, but in the SoftPot’s case, we are pressing, and for a knob we are rotating.

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Arduino Tachometer - Using a Hall Effect Sensor (A3144) to Measure Rotations from a Fan

Arduino tachometer used to calculate the rotational motion of a part. Tachometers read out revolutions per minute (RPM), which tells the user how often a rotating part completes one full rotation. RPM readings are used in the automotive, aerospace, and manufacturing fields. Tachometers can indicate fuel consumption and motor speed, safety of moving parts, and even wind speed indicators. In this tutorial, the speed of a fan is measured using a hall sensor and neodymium magnet to acquire an accurate depiction of fan speed.

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Capacitive Touch Sensor with Arduino

Capacitive sensing from human touch. Create a switch without any moving parts with an Arduino board and an inexpensive capacitive touch sensor.

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Arduino I2C OLED Display - Temperature and Humidity Display (SSD1306)

How to print temperature and humidity readings onto a 0.96 inch I2C OLED display. The device is DIYMall's inexpensive, high resolution (128x64 pixels), yellow and blue organic LED display that is designed for use with the Arduino platform. Together with a DHT22 temperature sensor, the tiny OLED screen will display real-time humidity and temperature data using an Adafruit library and an Arduino Uno board. This project can be expanded upon to print data from a wide array of sensors, and even grab data from the internet to print values for a smart and interactive display.

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Python Microcontroller: Getting Started with Adafruit's Trinket M0 and CircuitPython

In this tutorial I will cover one of the newest microcontroller interface languages, Python, and demonstrate Adafruit's powerful Trinket M0 microcontroller and its capabilities using Python as its programming language. Much of what is outlined below can be seen on Adafruit's website [UART communication, Trinket info, CircuitPython Basics].

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