Hackaday Prize 2023: AC Measurements Made Easy

October 12, 2023 by Bryan Cockfield 17 Comments

When working on simple DC systems, a small low-cost multimeter from the hardware store will get the job done well enough. Often they have the capability for measuring AC, but this is where cheap meters can get tripped up. Unless the waveform is a perfect sinusoid at a specific frequency, their simple algorithms won’t be able to give accurate readings like a high-quality meter will. [hesam.moshiri] took this as a design challenge, though, and built an AC multimeter to take into account some of the edge cases that come up when working with AC circuits, especially when dealing with inductive loads.

The small meter, an upgrade from a previous Arduino version that is now based on the ESP32, is capable of assessing root mean square (RMS) voltage, RMS current, active power, power factor, and energy consumption after first being calibrated using the included push buttons. Readings are given via a small OLED screen and have an accuracy rate of 0.5% or better. The board also includes modern design considerations such as galvanic isolation between the measurement side of the meter and the user interface side, each with its own isolated power supply. The schematics and bill-of-materials are also available for anyone looking to recreate or build on this design.

With the project built on an easily-accessible platform like the ESP32, it would be possible to use this as a base to measure other types of signals as well. Square and triangle waves, as well as signals with a large amount of harmonics or with varying frequencies, all need different measurement techniques in order to get accurate readings. Take a look at this classic multimeter to see what that entails.

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ESP32 Drives Tiny FM Radio

September 14, 2023 by Bryan Cockfield 21 Comments

Even as music streaming services and podcast apps dominate most of our listening time, it’s still a great idea to keep a radio on hand, if for nothing else than in emergency situations. After all, blizzards, hurricanes, and other natural disasters can quickly take out both home and mobile Internet access. If you’d like to have an FM radio with the absolute smallest footprint, take a look at this one built around an ESP32.

While the radio uses the ESP32 as the main control board hosted by a TTGO T-Display board which adds a 1.14 inch ST7789V IPS panel, it also makes use of the TEA5767 chip for handling the FM radio signals. As [Volos Projects] has it programmed, the ESP32 stores five preset channels which can be toggled using two buttons at the bottom of the device. There’s also some circuitry to handle output to headphones or a stereo.

For making the radio even smaller, some of the audio processing could be done on the ESP32 instead, although its much simpler to take a slightly larger footprint and offload this to an audio processing chip. Since the source code for this project is open, modifications could be done including adding seek/tune functionality instead of relying only on presets. If you’re not building this for emergencies, though, and your entire area is dominated by cookie cutter corporate-owned radio stations, an ESP32 with an internet connection is great for accessing better radio stations around the world.

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A Usable Arduino Debugging Tool

July 31, 2023 by Bryan Cockfield 16 Comments

For as popular as the Arduino platform is, it’s not without its problems. Among those is the fact that most practical debugging is often done by placing various print statements throughout the code and watching for them in the serial monitor. There’s not really a great way of placing breakpoints or stepping through code, either. But this project, known as eye2see, hopes to change that by using the i2c bus found in most Arduinos to provide a more robust set of debugging tools.

The eye2see software is set up to run on an Arduino or other compatible microcontroller, called the “probe”, which is connected to the i2c bus on another Arduino whose code needs to be debugged. Code running on this Arduino, which is part of the eye2see library, allows it to send debugging information to the eye2see probe. With a screen, the probe can act as a much more powerful debugger than would otherwise typically be available, being able to keep track of variables in the main program, setting up breakpoints, and outputting various messages on its screen.

The tool is not without its downsides, though. The library that needs to run on the host Arduino slows down the original program significantly. But for more complex programs, the tradeoff with powerful debugging tools may be worth it until these pieces of code can be removed and the program allowed to run unencumbered. If you’d like to skip needing to use a second Arduino, we’ve seen some other tools available for debugging Arduino code that can run straight from a connected PC instead.

Hackaday Prize 2023: Tilting Mechanical Panels Make A Beautiful Display

July 17, 2023 by Donald Papp 13 Comments

Mechanical displays use a variety of different methods to represent data with physical objects, and [AIRPOCKET]’s Mechanical Display aims to be a platform anyone can use. Each “pixel” in this display is a panel of some kind, and different effects can be had by moving individual panels to different angles. Not only can images be represented, but the patterns of the movements themselves can be beautiful as well.

The panels are an important part of how the display presents, so the design makes them easy to change out.

These sorts of displays are fertile ground for artistic expression (one memorable implementation of this basic idea was the wooden mirror, which used varnished tiles of wood) but anyone looking to use the concept has usually been on their own when it comes to implementation.

The idea [AIRPOCKET] has is to make this kind of installation easier to implement. This method uses economical mini RC servos and 3D-printed pieces to create modular segments that can be assembled into whatever configuration one may need.

The material of the panels matters, too. Just below the page break, you can see a large unit with each “pixel” consisting of a mirrored square that reflects daylight. There’s also a video of an earlier prototype that uses some ridged two-color pieces to create a simple 4×4 three-level greyscale display.

There are a lot of possibilities if [AIRPOCKET] can make this sort of display more easily accessible, and that makes it a contender in the 2023 Hackaday Prize.

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DisplayPort: A Better Video Interface

July 11, 2023 by Arya Voronova 75 Comments

Over the years, we’ve seen a good number of interfaces used for computer monitors, TVs, LCD panels and other all-things-display purposes. We’ve lived through VGA and the large variety of analog interfaces that preceded it, then DVI, HDMI, and at some point, we’ve started getting devices with DisplayPort support. So you might think it’s more of the same. However, I’d like to tell you that you probably should pay more attention to DisplayPort – it’s an interface powerful in a way that we haven’t seen before.

The DisplayPort (shortened as DP) interface was explicitly designed to be a successor to VGA and DVI, originating from the VESA group – an organization created by multiple computer-display-related players in technology space, which has previously brought us a number of smaller-scale computer display standards like EDID, DDC and the well-known VESA mount. Nevertheless, despite the smaller scale of previous standards, DisplayPort has since become a hit in computer display space for a number of reasons, and is more ubiquitous than you might realize.

You could put it this way: DisplayPort has all the capabilities of interfaces like HDMI, but implemented in a better way, without legacy cruft, and with a number of features that take advantage of the DisplayPort’s sturdier architecture. As a result of this, DisplayPort isn’t just in external monitors, but also laptop internal displays, USB-C port display support, docking stations, and Thunderbolt of all flavors. If you own a display-capable docking station for your laptop, be it classic style multi-pin dock or USB-C, DisplayPort is highly likely to be involved, and even your smartphone might just support DisplayPort over USB-C these days. Continue reading “DisplayPort: A Better Video Interface” →

A More Conspicuous Computer Assistant

June 25, 2023 by Bryan Cockfield 11 Comments

Back in the last century, especially in the ’40s to the ’60s, one of the major home decor trends was to install various home appliances, like the television or stereo, into its own piece of furniture. These were usually bulky, awkward, and incredibly heavy. And, since real life inspires art, most of the futuristic sci-fi technology we saw in movies and TV of the time was similarly conspicuous and physical. Not so with modern technology, though, where the trend now is to hide it out of the way and forget it exists. But [dermbrian] wanted some of his modern technology to have some of the mid-century visibility aesthetic so he made some modifications to his Amazon Echo.

The Echo itself remains largely unmodified, other than placing it inside a much larger cookie tin with some supporting electronics. For that, [dermbrian] found a relay board with a built-in microphone which switches the relay off when it detects sound so that when the Echo is activated, the sound from its speaker activates the module. From there it drives a series of blinkenlights which mimic the 60s computer aesthetic. Some custom fabrication and light diffusion methods were needed to get it to look just right, and a switch on the outside can disable the mechanism if it is getting triggered by background noise like music from his stereo.

While the appeal of this style may be lost on anyone who wasn’t a fan of the original Lost in Space, Star Trek, or Jetsons, it certainly holds a special significance for those who grew up in that era. It’s certainly not the first project we’ve seen to take a look back at the aesthetics of bygone eras, either. Take a look at this project which adds lenses to modern displays to give them the impression of antiquated CRT displays.

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A Look Back At Computer Displays

May 21, 2023 by Al Williams 10 Comments

These days, our video cards are actually as powerful as yesterday’s supercomputer and our monitors are bigger than the TVs most of us had as kids. But how did we get there? [RetroBytes] covers computer displays starting with the Colossus computer to today.

Back in the days of Colossus, of course, a display was actually a TeleType-like device printing on a roll of paper. The Manchester Baby actually had a crude display which was actually a Williams tube (no relation) that used phosphor persistence to store data. You could physically see memory on the tube or monitor it on a parallel tube — an early form of memory-mapped display.

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