Microcontrollers

2285 Articles

Exploring The RP2350’s UART-Bootloader

May 11, 2025 by 12 Comments

The RP2350 has a few advantages over its predecessor, one of which is the ability to load firmware remotely via UART, as [Thomas Pfister] has documented on his blog and in the video below.

[Thomas] had a project that needed more PWM than the RP2350 could provide, and hit upon the idea of using a second RP2350 as a port expander. Now, one could hard-code this, but dealing with two sets of firmware on one board can be annoying. That’s where the UART bootloader comes in: it will allow [Thomas] to program the port-expander RP2350 using the main microcontroller. Thus he only has to worry about one firmware, speeding up development.

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Mongoose Wizard new project dialog.

Web Dashboard And OTA Updates For The ESP32

May 10, 2025 by 10 Comments

Today we are happy to present a web-based GUI for making a web-based GUI! If you’re a programmer then web front-end development might not be your bag. But a web-based graphical user interface (GUI) for administration and reporting for your microcontroller device can look very professional and be super useful. The Mongoose Wizard can help you develop a device dashboard for your ESP32-based project.

In this article (and associated video) the Mongoose developers run you through how to get started with their technology. They help you get your development environment set up, create your dashboard layout, add a dashboard page, add a device settings page, add an over-the-air (OTA) firmware update page, build and test the firmware, and attach the user-interface controls to the hardware. The generated firmware includes an embedded web server for serving your dashboard and delivering its REST interface, pretty handy.

You will find no end of ESP32-based projects here at Hackaday which you could potentially integrate with Mongoose. We think the OTA support is an excellent feature to have, but of course there are other ways of supporting that functionality.

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A Single Chip Computer For The 8051 Generation

May 9, 2025 by 36 Comments

The Intel 8051 series of 8-bit microcontrollers is long-discontinued by its original manufacturer, but lives on as a core included in all manner of more recent chips. It’s easy to understand and program, so it remains a fixture despite much faster replacements appearing.

If you can’t find an original 40-pin DIP don’t worry, because [mit41301] has produced a board in a compatible 40-pin format. It’s called the single chip computer not because such a thing is a novelty in 2025, but because it has no need for the support chips which would have come with the original.

The modern 8051 clone in use is a CH558 or CH559, both chips with far more onboard than the original. The pins are brought out to one side only of the board, because on the original the other side would interface with an external RAM chip. It speaks serial, and can be used through either a USB-to-serial or Bluetooth-to-serial chip. There’s MCS-BASIC for it, so programming should be straightforward.

We can see the attraction of this board even though we reach for much more accomplished modern CPUs by choice. Several decades ago the original 8051 on Intel dev boards was our university teaching microcontoller, so there remains here a soft spot for it. We certainly see other 8051 designs, as for example this Arduino clone.

Train With Morse Master

May 4, 2025 by 15 Comments

Morse code can be daunting to learn when you’re new to the game, particularly if you need it to pass your desired radio license. However, these days, there are a great many tools to aid in the learning process. A good example is the Morse Master from [Arnov Sharma].

The Morse Master is a translator for Morse code, which works in two ways. You can access it via a web app, and type in regular letters which it then flashes out as code on its in-built LEDs. Alternatively, you can enter Morse manually using the physical key, and the results will be displayed on the web app. The Morse key itself is built into the enclosure using 3D printed components paired with a Cherry-style keyboard switch. It’s perhaps not the ideal solution for fast keying, with its limited rebound, but it’s a quick and easy way to make a functional key for practice purposes. If you want to go faster, though, you might want to upgrade to something more capable. We’d also love to see a buzzer added, since Morse is very much intended as an auditory method of communication.

We’ve seen some other great Morse code trainers before, too. If you’ve trained yourself in this method of communication, don’t hesitate to share your own learning tips below.

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Building An NRF52840 And Battery-Powered Zigbee Gate Sensor

April 30, 2025 by 23 Comments

Recently [Glen Akins] reported on Bluesky that the Zigbee-based sensor he had made for his garden’s rear gate was still going strong after a Summer and Winter on the original 2450 lithium coin cell. The construction plans and design for the unit are detailed in a blog post. At the core is the MS88SF2 SoM by Minew, which features a Nordic Semiconductor nRF52840 SoC that provides the Zigbee RF feature as well as the usual MCU shenanigans.

Previously [Glen] had created a similar system that featured buttons to turn the garden lights on or off, as nobody likes stumbling blindly through a dark garden after returning home. Rather than having to fumble around for a button, the system should detect when said rear gate is opened. This would send a notification to [Glen]’s phone as well as activate the garden lights if it’s dark outside.

Although using a reed relay switch seemed like an obvious solution to replace the buttons, holding it closed turned out to require too much power. After looking at a few commercial examples, he settled for a Hall effect sensor solution with the Ti DRV5032FB in a TO-92 package.

Whereas the average person would just have put in a PIR sensor-based solution, this Zigbee solution does come with a lot more smart home creds, and does not require fumbling around with a smartphone or yelling at a voice assistant to turn the garden lights on.

Read Motor Speed Better By Making The RP2040 PIO Do It

April 29, 2025 by 8 Comments

A quadrature encoder provides a way to let hardware read movement (and direction) of a shaft, and they can be simple, effective, and inexpensive devices. But [Paulo Marques] observed that when it comes to reading motor speeds with them, what works best at high speeds doesn’t work at low speeds, and vice versa. His solution? PicoEncoder is a library providing a lightweight and robust method of using the Programmable I/O (PIO) hardware on the RP2040 to get better results, even (or especially) from cheap encoders, and do it efficiently. Continue reading “Read Motor Speed Better By Making The RP2040 PIO Do It” →

Tinycorder Isn’t Quite A Tricorder, But…

April 28, 2025 by 12 Comments

The Star Trek tricorder was a good example of a McGuffin. It did anything needed to support the plot or, in some cases, couldn’t do things also in support of the plot. We know [SirGalaxy] was thinking about the tricorder when he named the Tinycorder, but the little device has a number of well-defined features. You can see a brief video of it working below the break.

The portable device has a tiny ESP32 and a battery. The 400×240 display is handy, but has low power consumption. In addition to the sensors built into the ESP32, the Tinycorder has an AS7341 light sensor, an air quality sensor, and a weather sensor. An odd combination, but like its namesake, it can do lots of unrelated things.

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