Microcontrollers

2145 Articles

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.

Continue reading “BBC Micro:Bit As Handheld Synthesizer” →

Giving Your Pets A Digital Squeak

December 15, 2022 by 4 Comments

A pet tracker has a particularly grueling set of requirements: small, light, rugged, incredibly long battery life, safe for the pet, and cheap. [Mihai Cuciuc] was looking at the options and wasn’t thrilled with any of them. So as any hacker would, he rolled his own, dubbed Squeak.

It uses an RN2483 module as it is a LoRAWAN module with publically available firmware from Microchip itself. This means [Mihai] could add his code and keep the modem code without having to reverse engineer everything or add a second microcontroller. In addition to the modem, there’s a GPS unit connected via UART. The clever part is the dual voltage regulators — the one powering the GPS is enabled or disabled by the RN2483. In addition, the RAM V_BACKUP line is always powered, which means the RN2483 can power up the GPS and let it get a quick fix (thanks to the RAM backup line).

To maximize the chances of a packet making it through, he made them only have the bare essentials. There are return packets to change the tracker’s mode (such as uplink interval or how often to capture GPS). With some cloud support, [Mihai] created infrastructure to capture the packets and relay them to Telegram. He can request the last location, receive updates, and change modes.

We’ve got you covered if you’re interested in tracking some of your dog’s other habits.

Push ESP32 Over The Air Updates From GitHub

December 13, 2022 by 21 Comments

Let’s say you’re working on an ESP32 project to send off to your grandma; something she can just plug in and it will start automatically monitoring her plant’s water levels. But you discover a critical flaw in the firmware and need to update it. Does she send it back? Do you walk her through dropping the update via the Arduino IDE OTA? The easiest way would be to plan and use something like esp_ghota, an OTA framework by [Justin Hammond].

OTA (Over-The-Air) updates are a fantastic feature of the ESP32, and we’ve covered libraries that make it easy. But compared to those earlier projects, esp_ghota takes a different approach. Rather than hosting a web server where someone can drop a binary, it looks at GitHub releases. [Justin] had to include a streaming JSON parser, as GitHub API responses tend to be beefy. The workflow is straightforward, push a new commit to your main branch on GitHub, and the action will trigger, building a few different versions. Your little plant watering reminder at your grandma’s will check every so often to see if a new version has been pushed and can update with rollback on littlefs, fatfs, and spiffs filesystems.

It’s an incredible project that we suspect will be very useful for many folks to update their projects. [Justin] even includes an example GitHub action and a sample ESP32 project.

A grid of 5 3D Printed projects with ESP-32 microcontroller boards

ESP32 Projects From Northwestern University’s Embedded Electronics Class

December 12, 2022 by 4 Comments

Northwestern University’s Embedded Electronics Class delivered a bumper crop of ESP-32 projects this year. The student teams recorded their progress on hackaday.io with project descriptions, logs, BOMs, diagrams, photos, and videos to share with other makers. While all utilized the web connection that the ESP32 offers some teams chose to use ESP32 Cams to incorporate photos, video, and computer vision. We love the variety of projects the teams created, some customized versions of consumer products and others new types of smart-devices. Continue reading “ESP32 Projects From Northwestern University’s Embedded Electronics Class” →

Old-School Video Switching Levels Up With Modern USB Control

December 10, 2022 by 13 Comments

Video effects and mixing are done digitally today, but it wasn’t always so. When analog ruled the video world, a big switch panel was key to effective results.

VIdeo like this was the result of combining different analog feeds with different effects. The better the hardware, the more was possible.

Devices like [Glen]’s Grass Valley Series 300 Crosspoint Switch Panel were an important part of that world. With tools like that, a human operator could set up a composited preview feed in true WYSIWYG style, and switch to live on cue. All done with relatively simple CMOS ICs and buttons. Lots and lots of buttons.

[Glen] reverse engineers the panel to show how it works, and most of the heavy lifting is done by the MC14051B analog multiplexer/demultiplexer, and the MC14532B 8-bit priority encoder. Once that’s figured out, the door is open to modernizing things a little by using a microcontroller to drive the device, turning it into a USB peripheral.

With a little design work, [Glen] builds a PCB around the EFM8UB2 8-bit microcontroller to act as a USB peripheral and control the switch panel, taking care of things like key scanning and lamp control. The last step: a GUI application for monitoring and controlling the panel over USB.

This isn’t [Glen]’s first time interfacing to vintage video mixing and switching, and as many of us know it’s sometimes tricky work to interface to existing hardware. We covered his earlier video switcher project using hardware that was not nearly as easy to work with as this one.

Pi Pico QR Display Hands Out WiFi Info With Style

December 8, 2022 by 3 Comments

At this point, you’re likely aware that you can store your wireless network’s credentials in a QR code, so that anyone who wants to connect with their smartphone need only scan the 2D barcode. Whether you print it out on paper, extrude it out of plastic, or paint the thing on the wall, it still works the same. It’s a neat trick for when you’ve got friends and family over, and saves you having to explain your ponderously long WPA key.

But what if you want to change up the encryption key every so often? Sure would be a hassle to have to repaint the wall. Enter this interesting project from [Predrag Mijatovic], which uses a few scripts to automatically set up a new encrypted guest WiFi network and present the appropriate QR code on an OLED display attached to a Raspberry Pi Pico. It’s a bit convoluted, and almost certainly won’t work on your network without significant tweaks, but we’re intrigued by the idea.

As [Predrag] explains, the whole thing is based on a Latvian MikroTik router that can be configured over SSH. A Bash script generates a new encryption key by base64 encoding the output /dev/urandom,  logs into the router to set up a new network using it, and then generates the matching ASCII QR code. With some sed trickery, the code is then embedded into a MicroPython program that gets uploaded to the connected Pi Pico.

In the video after the break [Predrag] takes us through the process manually so it’s easier to see what’s going on. Under normal circumstances, it would all happen automatically and would take just a few seconds to complete. We’d feel more comfortable if the scripts had some error correction that would allow them to gracefully exit if something goes wrong, but as a proof of concept, it certainly works.

We’d like to see this concept explored a bit further, perhaps using one of the physical QR code displays we’ve seen over the years. A programmable electronic paper display would also be a logical way to show off a dynamic QR code.

Continue reading “Pi Pico QR Display Hands Out WiFi Info With Style” →

Review: Inkplate 2 Shrinks Down, Adds Color

December 7, 2022 by 9 Comments

Regular Hackaday readers may recall the Inkplate family of devices: open source all-in-one development boards that combine the power and versatility of the ESP32 with electronic paper displays salvaged from commercial e-readers. By taking the sharp, high-speed, displays intended for readers such as Amazon’s Kindle and bundling it together with all the hardware and software you need to make it work, the Inkplate provided a turn-key platform for anyone looking to get serious with e-paper.

Given the fact that their screens were pulled from recycled readers, it’s no surprise the previous Inkplate entries came in familiar 6 and 10 inch variants. There was even an upgraded 6 inch model that benefited from newer reader technology by adopting a touch-sensitive backlit panel, which we took a close look at last year. Their large displays make them excellent for wall mounted applications, such as a household notification center or constantly-changing art display. Plus, as you might expect, the Inkplate is an ideal choice for anyone looking to roll their own custom e-reader.

But of course, not every application needs so much screen real estate. In fact, for some tasks, such a large display could be considered a liability. Seeing a void in their existing product lineup, the folks at Soldered Electronics (previously e-radionica) have recently unveiled the diminutive Inkplate 2. This new miniature Inkplate uses the same software library as its larger predecessors, but thanks to its 2.13 inch three-color display, lends itself to a wider array of potential projects. Plus it’s considerably cheaper than the larger Inkplate models, at just $35 USD.

Considering the crowd sourced funding campaign for the Inkplate 2 blew past its goal in just 72 hours, it seems clear there’s plenty of interest in this new smaller model. But if you’re still not sure if it’s the e-paper solution you’ve been waiting for, maybe we can help — the folks at Soldered sent along a pre-production version of the Inkplate 2 for us to play around with, so let’s take it for a test drive and see what all the fuss is about.

Continue reading “Review: Inkplate 2 Shrinks Down, Adds Color” →