Ryan Flowers writes, “A fun project for every QRP enthusiast is an L-match tuner. We’ve built a couple here at MiscDotGeek and our latest build inspired Billy Dunn (AF5HD) to build a similar tuner. We have to say, this one turned out better than ours did!”
App note from Maxim Integrated discussing strain gauge and accompanying circuit are used in today’s weight measurement applications. Link here (PDF)
Current laws and regulations require honesty, tolerance, and accuracy in weigh scales. The most commonly used weight-measurement element is the strain gauge. This application note explains how strain gauges are useful in multiple applications that must measure stress and pressure and their effects. The electronics of honest weigh scales are varied, and can provide the resolution and accuracy that each application demands.
Maxim’s app note on a highly compact Type-C charger solution. Link here (PDF)
A highly integrated solution, as seen with the MAX77860 USB Type-C 3A switch-mode charger, dramatically reduces system complexity by integrating the charger, the power path, the Safeout LDO, ADC, and the USB-C CC and BC 1.2 detection in a small 3.9mm x 4.0mm, 0.4mm pitch, WLP package. OTG functionality is seamlessly integrated without the need for an extra inductor. This level of integration simplifies the design, enabling the delivery of more power and more functionality in minimal PCB space.
This application note (PDF) from TI discusses the different aspects of the Overture series high-power solutions, and discusses three application circuits: parallel, bridged, and bridged/parallel configurations
The objective is to provide simple high-power solutions that are conservatively designed, highly reliable and have low part count. This document provides three specific, but not unique, application circuits that provide output power of 100W, 200W,
and above. These circuits are the parallel, bridged, and bridged/parallel configurations.
These three circuits are simple to understand, simple to build and require very few external components compared
to discrete power amplifier designs. Simplicity of design and few components make this solution much more reliable than discrete amplifiers. In addition, these circuits inherently possess the full protection of each individual IC that is very difficult and time consuming to design discretely. Finally, these circuits are well know and have been in industry for years.
The project is based on a Pro Micro, an Arduino-compatible ATmega 32u4 board (the 32u4 allowing to easily create USB devices). For iteration 1, I added a couple of buttons and a rotary encoder to a breadboard alongside the Pro Micro to see how I can get media controls over USB to work. Turns out, Nico Hood’s HID library makes that quite simple.
In the first post in this series, we built a miniature LED bicycle traffic signal using 3D printing, laser cutting, a sticker, and an Adafruit Neopixel Jewel. In this post, we’ll look at bringing the signal to life using a Particle Photon. We’ll start with basic code to blink the traffic signal green, yellow, and red then add code to control the color over the web using the Particle Cloud or locally using an iPad and the Art-Net protocol.
The 1750Hz tone bursts are often used to trigger repeaters. There are several methods to build 1750Hz tone generators which including TC5082 divider, using MCUs, etc.
In this post, I present another 1750Hz tone generator which I built using 74HC4060 high-speed 14-stage binary ripple counter and 7.168MHz crystal. In this design, 74HC4060 is used to drive the crystal and divide its output by 4096. By using 7.168MHz crystal, this circuit produces 1750.0Hz square wave output with a 50% duty cycle.
App note from Kionix about magnetometer integration challenges from the mobile equipment point of view, and gives guidelines for the mounting position of the magnetic sensor. Link here (PDF)
Electronic devices contain many parts which can affect a magnetic sensor. When deciding the mounting position, it is necessary to consider the types of materials and the amount of current carried in proximity of the magnetic sensor. Accuracy of an electronic compass depends upon getting clean geomagnetic data from the magnetic sensor output without errors caused by other magnetic elements. These errors need to be canceled by calibration or correction.
App note from Kionix on utilizing 2 linear accelerometers to determine angular rotational rates. Link here (PDF)
In many applications, customers would like to measure rotational motions (angular velocity, angular acceleration) in addition to linear motions. Most often, gyroscopes are added to their end product to obtain the rotational information. In some instances, customers already have a system that contains two or more accelerometers. With some understanding of fundamental physics, they can extract more than just linear acceleration data from their system.