Author: Bryan Cockfield

1710 Articles

Photography, The Stereo Way

December 19, 2022 by 19 Comments

Most consumer-grade audio equipment has been in stereo since at least the 1960s, allowing the listener to experience sounds with a three-dimensional perspective as if they were present when the sound was originally made. Stereo photography has lagged a little behind the stereo audio trend, though, with most of the technology existing as passing fads or requiring clumsy hardware to experience fully. Not so with the DIY stereoscopic cameras like this one produced by this group of 3D photography enthusiasts, who have also some methods to view the photos in 3D without any extra hardware.

The camera uses two imaging sensors to produce a stereo image. One sensor is fixed, and the other is on a slider which allows the user to adjust the “amount” of 3D effect needed for any particular photo. [Jim] is using this camera mostly for macro photography, which means that he only needs a few millimeters of separation between the two sensors to achieve the desired effect, but for more distant objects more separation can be used. The camera uses dual Raspberry Pi processors, a lithium battery, and a touch screen interface. It includes a ton of features as well including things like focus stacking, but to get a more full experience of this build we’d highly recommend checking out the video after the break.

As for viewing the photographs, these stereoscopic 3D images require nothing more than a little practice to view them. This guide is available with some simple examples to get started, and while it does at first feel like a Magic Eye puzzle from the late 90s, it quickly becomes intuitive. Another guide has some more intricate 3D maps at the end to practice on as well. This is quite the step up from needing to use special glasses or a wearable 3D viewer of some sort. There are also some methods available to create 3D images from those taken with a regular 2D camera as well.

Thanks to [Bill] for the tip and the additional links to the guides for viewing these images!

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BBC Micro:Bit As Handheld Synthesizer

December 17, 2022 by 4 Comments

The BBC Micro:bit, while not quite as popular in our community as other microcontroller development boards, has a few quirks that can make it a much more interesting piece of hardware to build a project around than an Arduino. [Turi] took note of these unique features and decided that it was the perfect platform to build a synthesizer on.

The Micro:bit includes two important elements that make this project work: the LED matrix and a gyro sensor. [Turi] built a 5×5 button matrix for inputs and paired each to one of the diodes, which eliminates the problem of false inputs. The gyro sensor is used for detuning, which varies the pitch of any generated sound by a set amount according to the orientation of the device. It also includes a passive low-pass filter to make the sound more pleasant to the ear, especially for younger players of the machine. He’s released the source code on his GitHub page for anyone interested in recreating it.

While this was a one-off project for [Turi], he notes that using MicroPython to program it instead of C led to a lot of unnecessary complications, and the greater control allowed by C would enable some extra features with less hassle. Still, it’s a fun project that really showcases the unique features of this board, much like this tiny Sumo robot we covered over the summer.

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Kids’ Jukebox Based On Arduino With RFID

December 16, 2022 by 10 Comments

Consumer electronics aimed at young children tend to be quite janky and cheap-looking, and they often have to be to survive the extreme stress-testing normal use in this situation. You could buy a higher quality item intended for normal use, but this carries the risk of burning a hole in the pockets of the parents. To thread the needle on this dilemma for a child’s audiobook player, [Turi] built the Grimmboy for a relative of his.

Taking its name from the Brothers Grimm, the player is able of playing a number of children’s stories and fables in multiple languages, with each physically represented by a small cassette tape likeness with an RFID tag hidden in each one. A tape can be selected and placed in the player, and the Arduino at the center of it will recognize the tag and play the corresponding MP3 file stored locally on an SD card. There are simple controls and all the circuitry to support its lithium battery as well. All of the source code that [Turi] used to build this is available on the project’s GitHub page.

This was also featured at the Arudino blog as well, and we actually featured a similar project a while ago with a slightly different spin. Both are based on ideas from Tonuino, an open source project aimed at turning Arduinos into MP3 players. If you’re looking to build something with a few more features, though, take a look at this custom build based on the RP2040 microcontroller instead.

Antenna Mount Designed For On-The-Go SDR

December 16, 2022 by 15 Comments

Software-defined radio is all the rage these days, and for good reason. It eliminates or drastically reduces the amount of otherwise pricey equipment needed to transmit or even just receive, and can pack many more features than most affordable radio setups otherwise would have. It also makes it possible to go mobile much more easily. [Rostislav Persion] uses a laptop for on-the-go SDR activities, and designed this 3D printed antenna mount to make his radio adventures much easier.

The antenna mount is a small 3D printed enclosure for his NESDR Smart Dongle with a wide base to attach to the back of his laptop lid with Velcro so it can easily be removed or attached. This allows him to run a single USB cable to the dongle and have it oriented properly for maximum antenna effectiveness without something cumbersome like a dedicated antenna stand. [Rostislav] even modeled the entire assembly so that he could run a stress analysis on it, and from that data ended up filling it with epoxy to ensure maximum lifespan with minimal wear on the components.

We definitely appreciate the simple and clean build which allows easy access to HF and higher frequencies while mobile, especially since the 3D modeling takes it a step beyond simply printing a 3D accessory and hoping for the best. There’s even an improved version on his site here. To go even one step further, though, we’ve seen the antennas themselves get designed and then 3D printed directly.

Lisp Runs This Microcontroller Pendant

December 10, 2022 by 20 Comments

As a programming language, Lisp has been around longer than any other active language except for Fortran. To anyone who regularly uses it, it’s easy to see why: the language allows for new syntax and macros to be created fluidly, which makes it easy to adapt it to new situations, like running it on a modern Atmel microcontroller to control the LEDs on this star pendant.

The pendant has simple enough hardware — six LEDs arranged around the points of the star, all being driven by a small ATtiny3227 operating from a coin cell battery. This isn’t especially spectacular on it’s own, but this particular microcontroller is running an integer version of a custom-built Lisp interpreter called uLisp. The project’s creator did this simply because of the whimsy involved in running a high-level programming language on one of the smallest microcontrollers around that would actually support the limited functionality of this version of Lisp. This implementation does stretch the memory and processing capabilities of the microcontroller quite a bit, but with some concessions, it’s able to run everything without issue.

As far as this project goes, it’s impressive if for nothing other than the ‘I climbed the mountain because it was there’ attitude. We appreciate all kinds of projects in that same vein, like this Arduino competitor which supports a programming language with only eight commands, or this drone which can carry a human.

Using GitHub Actions To Brew Coffee

December 10, 2022 by 27 Comments

It’s getting harder and harder to think of a modern premium-level appliance that doesn’t come with some level of Internet connectivity. These days it seems all but the cheapest refrigerators, air purifiers, and microwaves include wireless capabilities — unfortunately they’re often poorly implemented or behind a proprietary system. [Matt] recently purchased a high-end coffee maker with Bluetooth functionality which turned out to be nearly useless, and set to work reverse-engineering his coffee maker and adapting it to work by sending commands from GitHub.

Since the wireless connectivity and app for this coffee maker was so buggy and unreliable, [Matt] first needed to get deep into the weeds on Bluetooth Low Energy (BTLE). After sniffing traffic and identifying the coffee maker, he set about building an interface for it in Rust. Once he is able to send commands to it, the next step was to integrate it with GitHub, so that filing issues on the GitHub interface sends the commands from a nearby computer over Bluetooth to the coffee maker, with much more reliability than the coffee maker came with originally.

Using [Matt]’s methods, anyone stuck with one of these coffee makers, a Delonghi Dinamica Plus, should be able to reactivate the use of its wireless functionality. While we’d hope that anyone selling a premium product like this would take a tiny amount of time and make sure that the extra features actually work, this low bar seems to be oddly common for companies to surmount. But it’s not required to pick up an expensive machine like this just to remotely brew a cup of coffee. You can do that pretty easily with a non-luxury coffee maker and some basic wireless hardware.

Ultimate Game And Watch Has Support For NES

December 9, 2022 by 2 Comments

We’ve talked about feature creep plenty of times around here, and it’s generally regarded as something to be avoided when designing a prototype. It might sound good to have a lot of features in a build, but this often results in more complexity and more difficulty when actually bringing a project to fruition. [Brendan] has had the opposite experience with this custom handheld originally designed for Game and Watch games, though, and he eventually added NES and Game Boy functionality as well.

As this build was originally intended just for Game and Watch games, the screen is about the size of these old games, and while it can easily mimic the monochrome LCD-style video that would have been present on these 80s handhelds, it also has support for color which means that it’s the perfect candidate for emulating other consoles as well. It’s based around a Raspberry Pi Zero 2W and the enclosure is custom printed and painted. Some workarounds for audio had to be figured out, though, since native analog output isn’t supported, but it still has almost every feature for all of these systems.

While we’ve seen plenty of custom portable builds from everything from retro consoles to more modern ones, the Game and Watch catalog is often overlooked. There are a few out there, but in this case we appreciate the feature creep that allowed this build to support Game Boy and NES games as well.