Microcontrollers

2285 Articles

This ESP8266 Dev Board Has A Surprising Story Behind It

April 23, 2021 by 24 Comments

If you’re looking to get started with the ESP8266, there’s no shortage of development boards out there to select from. But we don’t think you’ll find one with a more unique a backstory than the open source ME-ESP8266. That’s because Malouf, the company that makes the $20 USD board, is a home goods company better known for their pillows and bed frames.

So how do you go from mattress toppers to microcontrollers? Well, as unlikely as it might seem, the missing element is Toys R’ Us. Or more specifically, the liquidation of Toys R’ Us. A Texas distribution center Malouf purchased from the iconic toy retailer included an automated conveyor belt system to move product through the gargantuan building, but unfortunately, they couldn’t get it to work with their existing system. The company decided to use their in-house team of engineers to solve the problem, and the ME-ESP8266 was born.

It turns out that an ESP8266 board developed to move bedding around an old Toys R’ Us warehouse has a lot of useful features for hackers and makers. It’s got an integrated relay, 16 MB of flash storage, an IR receiver, beefy screw terminals, and a 2.54mm-pitch GPIO pin header. There’s even a MAX232 on the board so it can talk to RS-232 devices. The hardware is compatible with the standard Arduino IDE as a “Generic ESP8266 Module”,  so you’ll have no problem using existing libraries and example code.

Now under normal circumstances, the public would never know about this sort of behind the scenes engineering. But instead of keeping their new ESP board to themselves, the team at Malouf got the go ahead from the company’s Chief Technology Officer (CTO) to release it as an open source project. Even more impressive, they got the company to put the board into production so it could be sold to the public. So today we not only learned that bedding companies have CTOs, but that they can be exceptionally open-minded.

Our hats off to the engineers at Malouf and the forward thinking brass that green lit production of the ME-ESP8266. It’s not the first interesting development to come from the liquidation of Geoffrey’s kingdom, but it just might be the most useful.

Stepper Motor Analyzer Reveals All

April 23, 2021 by 15 Comments

In theory, you really don’t need much to work with electronics. A scope ought to do everything. However, for special purposes, it is handy to have meters, logic analyzers, and other special-purpose instruments. If you work on motion systems like 3D printers and CNC machines, you ought to have a way to look at stepper motors. You don’t? [Zapta] has a great Simple Stepper Motor Analyzer and [Teaching Tech] has a great video (see below) that shows some of the great things it can do.

What can it do? It analyzes the motor in place and can visualize what’s happening during stepping, microstepping, and other operating modes. Connecting the instrument is easy since you just use a four-pin pass-through connector.

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DIY Wireless Serial Adapter Speaks (True) RS-232

April 18, 2021 by 80 Comments

There is a gotcha lurking in wait for hackers who look at a piece of equipment, see a port labeled “Serial / RS-232”, and start to get ideas. The issue is the fact that the older the equipment, the more likely it is to be a bit old-fashioned about how it expects to speak RS-232. Vintage electronics may expect the serial data to be at bipolar voltage levels that are higher than what the typical microcontroller is used to slinging, and that was the situation [g3gg0] faced with some vintage benchtop equipment. Rather than deal with cables and wired adapters, [g3gg0] decided to design a wireless adapter with WiFi and Bluetooth on one end, and true RS-232 on the other.

The adapter features an ESP32 and is attached to a DB-9 plug, so it’s nice and small. It uses the ST3232 chip to communicate at 3 V logic levels on the microcontroller side, supports bipolar logic up to +/-13 V on the vintage hardware side, and a rudimentary web interface allows setting hardware parameters like baud rate. The nice thing about the ST3232 transceiver is that it is not only small, but can work from a 3 V supply with only four 0.1 uF capacitors needed for the internal charge pumps.

As for actually using the adapter, [g3gg0] says that the adapter’s serial port is exposed over TCP on port 23 (Telnet) which is supported by some programs and hardware. Alternately, one can connect an ESP32 to one’s computer over USB, and run firmware that bridges any serial data directly to the adapter on the other end.

Design files including schematic, bill of materials, and PCB design are shared online, and you can see a brief tour of the adapter in the video, embedded below.

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Replacing An ESP8266 Clone With The Real Thing

April 17, 2021 by 19 Comments

The first time [konbaasiang] ordered some ceiling LED lights from Tuya, he was pleased to find they contained an ESP-12F that could easily be flashed with a different firmware. So when he ordered 30 more of them at a cost of nearly $900 USD, you can understand his frustration to find that the popular WiFi-enabled microcontroller had been swapped out for a pin-compatible clone that Tuya developed called the WB3L.

Some people would have just chalked this one up to bad luck and used the Tuya-supplied software to control their new lights, but not [konbaasiang]. Since the new chip was outwardly identical to the ESP8266, he decided to take the nuclear option and replace them with the genuine article. With a comfortable spot to work from and a nice microscope, he started on his desoldering journey.

Now it would have been nice if he could have just dropped in a real ESP-12F and called it a day, but naturally, it ended up being a bit more complex than that. The WB3L apparently doesn’t need external pull up and pull down resistors, but [konbaasiang] needed them for the swap to work. He could have come up with some kind of custom adapter PCB, but to keep things simple he decided to run a pair of through hole resistors across the top of the ESP-12F for GPIO 1/2, and use a gingerly placed SMD resistor to hold down GPIO 15.

[konbaasiang] reports that all 30 of the lights survived the transplant and are now running his own  homebrew firmware. While this story had a happy ending, it’s still a cautionary tale. With a growing trend towards replacing the venerable ESP8266 with cheaper and less hacker-friendly silicon, buying IoT hardware with the intent to replace its firmware is likely to get riskier in the near future.

The Beat Goes On With This ESP32 Page Turner

April 16, 2021 by 3 Comments

Looking for a hands-free way to page through sheet music on an iPad, [The_Larch] came up with this simple Bluetooth input device based on the ESP32. The microcontroller just needed to have two switches wired into the GPIO pins, in this case the same heavy-duty plungers you’d find on a guitar pedal, and a USB bulkhead pass-through to provide power. Thanks to the excellent ESP32-BLE-Keyboard library, it only took a few lines of code to fire off the appropriate key strokes when the left or right button was pressed.

While undeniably a simple project from an electronics standpoint, the wooden enclosure [The_Larch] built is an interesting change of pace from the 3D printed fare we normally see around these parts. It started life as strips of oak reclaimed from an old kitchen table, which were laminated together to make a solid block. A large spade bit was then used to bore into the block to make a void for the electronics, and a second flat piece of oak was fashioned into a front panel.

Creating Bluetooth input devices with the ESP32 is so incredibly straightforward that we’re honestly a little surprised we don’t see the trick used more often. Especially when you consider all of the custom made keyboards that have graced these pages over the last couple of years. The tools are available for anyone who wants them, so you have to wonder if hackers just aren’t fond of using Bluetooth for something as important as a keyboard?

An RP2040 Board Designed For Machine Learning

April 13, 2021 by 30 Comments

Machine learning (ML) typically conjures up ideas of fancy code requiring oodles of storage and tons of processing power. However, there are some ML models that, once trained, can readily be run on much more spartan hardware – even a microcontroller! The RP2040, star of the Raspberry Pi Pico, is one such chip up to the task, and [Arducam] have announced a board aiming to employ it to those ends – the Pico4ML.

The board goes heavy on the hardware, equipping the RP2040 with plenty of tools useful for machine learning tasks. There’s a QVGA camera on board, as well as a tiny 0.96″ TFT display. The camera feed can even be streamed live to the screen if so desired. There’s also a microphone to capture audio and an IMU, already baked into the board. This puts object, speech, and gesture recognition well within the purview of the Pico4ML.

Running ML models on a board like the Pico4ML isn’t about robust high performance situations. Instead, it’s intended for applications where low power and portability are key. If you’ve got some ideas on what the Pico4ML could do and do well, sound off in the comments. We’d probably hook it up to a network so we could have it automatically place an order when we yell out for pizza. We’ve covered machine learning on microcontrollers before, too – with a great Remoticon talk on how to get started!

Antique Map Of Paris With Modern Tech

April 10, 2021 by 7 Comments

There’s plenty to love about antiques, from cars, furniture, to art. While it might be a little bit of survivorship bias, it’s easy to appreciate these older things for superior quality materials, craftsmanship, or even simplicity. They are missing out on all of our modern technology, though, so performing “restomods” on classics is a popular activity nowadays. This antique map of Paris, for example, is made of a beautiful hardwood but has been enhanced by some modern amenities as well.

At first the creator of this project, [Marc], just wanted to give it some ambient lighting, but it eventually progressed over the course of two years to have a series of Neopixels hidden behind it that illuminate according to the current sun and moon positions. The Neopixels get their instructions from an ESP8266 which calculates these positions using code [Marc] wrote himself based on the current date. Due to the limitations of the ESP8266 it’s not particularly precise, but it gets the job done to great effect.

To improve on the accuracy, [Marc] notes that an ESP32 could be used instead, but we can give the ESP8266 a pass for now since the whole project is an excellent art installation even if it is slightly off on its calculations. If you need higher accuracy for tracking celestial objects, you can always grab a Raspberry Pi too.