Author: Bryan Cockfield

1754 Articles

Building A Weather Display In Rust

September 29, 2023 by 21 Comments

We’ve seen a lot of weather displays over the years, and plenty of the more modern ones have been using some form of electronic paper. So what makes this particular build from [Harry Stern] different? The fact that the firmware running on the ESP32 microcontroller at its heart was developed in Rust.

The weather station itself is capable of operating for several months on its rechargeable NiMH battery bank. The Rust section of the project is in two parts, the first of which runs on a server which downloads the weather data and aggregates it into an image. The second part runs on the ESP32 using esp-idf which configures peripherals, turns on and connects to Wi-Fi, retrieves the image from the server, displays the image and then puts the display to sleep. By doing the heavy lifting on the server, the display should be able to run for longer than it would if everything was happening on the ESP32.

The project code is available from this GitHub page which should allow even Rust beginners to follow along, and the case file is also available for those with a 3D printer. [Harry] has a few upgrades planned for future releases as well, including a snap-fit case, a custom PCB, and improved voltage regulator for better battery life, and enhanced error handling for the weather API. And Rust isn’t the only interesting part of this project, either. As prices for e-paper displays continue to fall, more and more of them are found in projects like weather stations and even complete laptops which use these displays exclusively.

Investigating The Fourth Passive Component

September 27, 2023 by 45 Comments

When first learning about and building electronic circuits, the first things all of us come across are passive components such as resistors, capacitors, and inductors. These have easily-understandable properties and are used in nearly all circuits in some way or another. Eventually we’ll move on to learning about active components like transistors, but there’s a fourth passive circuit component that’s almost never encountered. Known as the memristor, this mysterious device is not quite as intuitive as the other three, so [Andrew] created an Arduino shield to investigate their properties.

Memristors relate electric charge and magnetic flux linkage, which means that their resistance changes based on the current that passes through them. As their name implies, this means they have memory, and retain their properties even after power is removed. [Andrew] is testing three different memristors, composed of tungsten, carbon, and chromium, using this specialized test set. The rig is based on an Arduino Uno and has a few circuit components that can be used as references and generates data on the behavior of the memristors under various situations.

The memristors used here do exhibit expected behavior when driven with positive voltage signals, but did exhibit a large amount of variability when voltage was applied in a negative direction. [Andrew] speculates that using these devices for storage would be difficult and would likely require fairly bespoke applications for each type. But as the applications for these seemingly bizarre circuit components increase, we expect them to improve much like any other passive component.

Continue reading “Investigating The Fourth Passive Component” →

Bending Light To Fit Technology

September 22, 2023 by 3 Comments

Solar power is an excellent way of generating electricity, whether that’s for an off-grid home or for the power grid. With no moving parts maintenance is relatively low, and the downsides of burning fuel are eliminated as well. But as much as it’s revolutionized power generation over the last few decades, there’s still some performance gains to be made when it comes to the solar cells themselves. A team at Stanford recently made strides in improving cell efficiency by bending the properties of sunlight itself.

In order to generate electricity directly from sunlight, a photon with a specific amount of energy needs to strike the semiconductor material. Any photons with higher energy will waste some of that energy as heat, and any with lower energy won’t generate electricity. Previous methods to solve this problem involve using something similar to a prism to separate the light out into colors (or energies) that correlate to specific types of cells calibrated specifically for those colors. This method does the opposite: it changes the light itself to an color that fits the semiconductor material. In short, a specialized material converts the energy from two lower-energy photons into a single higher-energy photon, which then strikes the solar panel to create energy.

By adding these color-changing materials as a layer to a photovoltaic solar panel, the panel can generate more energy with a given amount of light than a traditional panel. The major hurdle, as with any research, is whether or not this will be viable when produced at scale, and this shows promise in that regard as well. There are other applications for these materials beyond photovoltaics as well, and the researchers provide an excellent demonstration in 3D printing. By adding these color-change materials to resin, red lasers can be used instead of blue or ultraviolet lasers to cure resin in extremely specific locations, leading to stronger and more accurate prints.

Atari Gets Semi-Modern Video Output

September 20, 2023 by 12 Comments

The Atari 2600 is a historical enigma in many ways. On one hand, it was the most popular gaming console of its era, but it was also at the center of the video game crash of 1983 due to the poor quality of its games at the time. It is a fascinating system in many ways that are still relevant today, especially when it comes to pushing hardware much farther than it was designed to go. [nicole] brings us a project that overcomes some of the limitations in its hardware to provide a more modern video output.

At the heart of the Atari is a custom chip called teh Television Interface Adapter (TIA) that generates the console’s video signal as well as handling controller information and a few other tasks. It was designed at a time where memory was expensive, and essentially trades programmer effort to reduce memory requirements. Interestingly, it separates luminance and chrominance information much like S-video does, so that’s where [nicole] focused their efforts. Thanks to some help from an adapter board, the video signals can be intercepted and reprocessed for the S-video standard instead of using RF modulation to send video data out, although this does involve some soldering and modifying of the original Atari hardware. In [nicole]’s case this was a little more involved due to the differences of the 2600jr compared to more standard versions of the console.

While S-video isn’t modern in the strictest sense, as a standard from 1987 it is a huge step forward compared to the available video output methods available in the 1970s when the 2600 was first produced. Plenty of older consoles and other hardware like VCRs and the like used S-video, so if you have a retro gaming setup complete with a CRT you might want to take a look at this 12-input A/V switch to keep everything managed.

Latency Meter For Accurate Gaming

September 19, 2023 by 17 Comments

The gaming world experienced a bit of a resurgence in 2020 that is still seen in the present day. Even putting aside the effects from the pandemic, the affordability and accessibility has arguably never been better. Building a gaming PC can have its downsides, though, and a challenging issue to troubleshoot is input lag or input latency. This is something that’s best measured with standalone hardware, and if this is an issue on your setup you may want to take a look at this latency meter.

Unlike other measurement devices that use the time between a mouse button input and the monitor’s display of a bullet or shooting event, this one looks at mouse movement and the change in the scene instead. This makes it much more versatile than other methods since it’s independent of specific actions, and can be used in any game without any specific events needed to perform the measurement. A camera phototransistor is placed on the monitor’s top edge and the Arduino-based device sends mouse commands to the computer while measuring the time between those commands and the shift in the image on the monitor.

The project is open source, so with the right hardware it’s possible to build one to troubleshoot latency issues or just to learn more about a particular hardware configuration’s behavior. Arduinos and other microcontrollers have been doing all kinds of things by pretending to be human interface devices like this for a while now. One of our favorites of late was this effects pedal that replicates musical effects on mice and keyboards.

Printed Upgrades Improve Cheap Digital Microscope

September 19, 2023 by 7 Comments

Digital microscopes used to be something that only labs or universities might have, but as image sensor technology has progressed, the prices have fallen to the point that any classroom or hobbyist can easily obtain a usable device. The only problem is that a lot of features and quality have been lost to make some of these digital microscopes more affordable. In an effort to add some of these creature comforts back into more inexpensive devices, [Marb’s lab] has created a special carriage for one of these microscopes.

The first addition to the microscope is improved lighting. To accomplish this, three LEDs were built into custom housings and wired to a purpose-built LED driver board coupled with a voltage regulator. Two of the LED housings were attached to the end of adjustable arms, allowing them to be pointed in whichever direction is needed. The third is situated directly below the microscope underneath the stage. These are all mounted to a large, sturdy PVC base which also holds an adjustable carriage for the microscope itself. This allows much more fine-tuning of the distance between the sample and the microscope than it otherwise would have had.

For just a few dollars and a little bit of effort, the usability of a device like this is greatly improved. If you want to take the opposite approach and really go all-out for your microscope, though, take a look at these microscopes used for PCB circuit construction and troubleshooting or even this electron microscope for viewing things at a much higher magnification than any optical system would allow.

Continue reading “Printed Upgrades Improve Cheap Digital Microscope” →

Sailor Hat Adds Graceful Shutdown To Pis

September 18, 2023 by 45 Comments

Even though Windows and other operating systems constantly remind us to properly eject storage devices before removing them, plenty of people won’t heed those warnings until they finally corrupt a drive and cause all kinds of data loss and other catastrophes. It’s not just USB jump drives that can get corrupted, though. Any storage medium can become unusable if certain actions are being taken when the power is suddenly removed. That includes the SD cards on Raspberry Pis, too, and if your power isn’t reliable you might consider this hat to ensure they shut down properly during power losses.

The Raspberry Pi hat is centered around a series of supercapacitors which provide power for the Pi temporarily. The hat also communicates with the Pi to let it know there is a loss of power, so that the Pi can automatically shut itself down in that situation to prevent corrupting the memory card. The hat is more than just a set of backup capacitors, though. The device is capable of taking input power from a wide range of sources and filtering it for the power requirements of the Pi, especially in applications like boats and passenger vehicles where the input power might be somewhat noisy. There’s an optocoupled CAN bus interface as well for those looking to use this for automotive applications.

The entire project is also available on the project’s GitHub page for those wishing to build their own. Some sort of power backup is a good idea for any computer, though, not just Raspberry Pis. We’ve seen uninterruptible power supplies (UPS) with enough power to run an entire house including its computers, to smaller ones that’ll just keep your Internet online during a power outage.

Continue reading “Sailor Hat Adds Graceful Shutdown To Pis” →