Microcontrollers

2301 Articles

Even More Firmware In Your Firmware

October 1, 2020 by 13 Comments

There are many ways to update an embedded system in the field. Images can fly through the air one a time, travel by sneaker or hitch a ride on other passing data. OK, maybe that’s a stretch, but there are certainly a plethora of ways to get those sweet update bytes into a target system. How are those bytes assembled, and what are the tools that do the assembly? This is the problem I needed to solve.

Recall, my system wasn’t a particularly novel one (see the block diagram below). Just a few computers asking each other for an update over some serial busses. I had chosen to bundle the payload firmware images into the binary for the intermediate microcontroller which was to carry out the update process. The additional constraint was that the blending of the three firmware images (one carrier and two payload) needed to happen long after compile time, on a different system with a separate toolchain. There were ultimately two options that fit the bill.

The system thirsty for an update

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Pulse Generator Does The Job With An STM8

October 1, 2020 by 16 Comments

When working with hardware, whether a repair or a fresh build, it’s often necessary to test something. Depending on what you’re working with, this can be easy or a total pain if you can’t get the right signal to the right place. To eliminate this frustrating problem, [WilkoL] built a useful pulse generator for use in the lab.

[WilkoL] notes that historically, the job of generating pulses of varying length and frequency would be achieved with a smattering of 555 timers. While this is a perfectly cromulent way to do so, it was desired to take a different approach for the added flexibility modern hardware can offer. The pulse generator is instead built around an STM8 microcontroller; an unusual choice in this era, to be sure. [WilkoL] specified the part for its incredibly low cost, and highly capable timer hardware – perfect for the job.

Combined with an ST7735 TFT LCD screen, and programmed in bare metal for efficiency’s sake, the final project is installed in a project box with controls for frequency and pulse length – no more, no less. Capable of pulse lengths from 250 ns to 90 s, and frequencies from 10 mHz to 2 MHz, it’s a tool that should be comfortable testing everything from servos to mechanical counters.

Of course, if you need to get down to picosecond timescales, an avalanche pulse generator might be more your speed. Video after the break.

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ESP32 Vulnerability Affects Older Chips

September 24, 2020 by 24 Comments

There is a scene from the movie RED (Retired, Extremely Dangerous) where Bruce Willis encounters a highly-secure door with a constantly changing lock code deep inside the CIA. Knowing the lock would be impossible to break, he simply destroyed the wall next to the door, reached through, and opened the door from the other side. We thought about that when we saw [raelize’s] hack to bypass the ESP32’s security measures.

Before you throw out all your ESP32 spy gadgets, though, be aware that the V3 silicon can be made to prevent the attack. V1 and V2, however, have a flaw that — if you know how to exploit it — renders secure boot and flash encryption almost meaningless.

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Circuit Board Origami Puts You Face-to-Face With Low-Poly Electronics

September 21, 2020 by 16 Comments

Paper craft has been around almost as long as paper itself. It’s fun to mimic paper craft and origami with low-poly 3D prints, and [Stephen Hawes] wondered whether it could be done with copper-clad PCBs. Two years after the question arose, we have the answer in the form of a fantastical mask with light-up eyes. Check it out in the video below.

[Stephen] started with a model (Update: [kongorilla]’s 2012 low poly mask model from back in 2012 was the starting point for this hack) from the papercraft program Pepakura Designer, then milled out dozens of boards. Only a few of them support circuitry, but it was still quite the time-consuming process. The ATmega32U4 on the forehead along with the fold-traversing circuitry serve to light up the WS2812B eyes. Power runs up the copper tube, which doubles as a handy mounting rod to connect to the 3D printed base.

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A Big Computer Needs A Big Keyboard

September 19, 2020 by 36 Comments

It seems like many keyboard aficionados have been gravitating towards ever smaller boards, but not [Ren]. He’s mostly completed a 433% keyboard with a whopping 450 distinct keys. Using two off the shelf PCBs and Teensy to control it all, this keyboard means you’ll never need to strain to make some awkward chord.

The PCBs have a diode matrix arrangement for 225 keys, which we would have thought was big enough. After all, a Scrabble board has 225 squares, so we assume that’s why the vendor calls them scrabbleboards. Honestly, we’re jealous someone has the desk space for this monster. We were also thinking what other sorts of switch-like sensors you could use with this board. Imagine a home system, for example, with 225 occupancy sensors, each with its own key you could easily read via USB.

There was a time when building your own keyboard of any sort would have been challenging. But now there’s a cottage industry supplying chips, switches, caps, and PCBs to those looking to craft their own custom input devices. The ready availability of 3D printers has also sparked a minor revolution in custom keyboard enclosures and keycaps.

If you’re a fan of the tiny keyboards, we’ve seen some impressive specimens that might catch your fancy. If nothing else, at least they require less soldering. Especially when they only have seven keys.

Thanks [ptkwilliams] for the tip!

Casio Computer Rebuild Puts New Wine In An Old Bottle

September 18, 2020 by 8 Comments

With a glut of vintage consumer electronics available from eBay it should be easy to relive your glory days, right? Unfortunately the march of time means that finding gear is easy but finding gear that works is not. So was the case when [Amen] acquired not one, but two used calculator/computer units hoping to end up with one working device. Instead, he went down the rabbit hole of redesigning his own electronics to drive the Casio QT-1 seen here.

Especially interesting is the prototyping process for the replacement board. [Amen] used a “BluePill” STM32 microcontroller board at its heart, and used point-to-point soldering for the rest of the circuitry on a rectangle of protoyping board. That circuit is non-trivial, needing a 23 V source to drive the original VFD from the computer, a battery-backed real-time-clock (MCP7940), and a GPIO expander to scan the keys on the keypad.

It worked great, but couldn’t be cut down to fit in the case. The solution was a PCB designed to fit the footprint of the original. The modern guts still need more firmware work and a couple of tweaks like nudging that 23 V rail a bit higher to 26 V for better brightness, but the work already warrants a maniacal cry of “It’s Alive!”.

This isn’t [Amen’s] first rodeo. Back in March we looked in on another vintage Casio refurb that sniffed out the display protocol.

Radon Monitor Recreates Steam Gauge With E-Ink

September 18, 2020 by 11 Comments

While the full steampunk aesthetic might be a bit much for most people, those antique gauges do have a certain charm about them. Unfortunately, implementing them on a modern project can be somewhat tricky. Even if you’ve got a stock of old gauges laying around, you’ve still got to modify the scale markings and figure out how to drive them with digital electronics. While we’ve seen plenty of people do it over the years, there’s no debating it’s a lot harder than just wiring up an I2C display.

But maybe it doesn’t have to be. With his Rad-O-Matic, [Hans Jørgen Grimstad] created a pretty convincing “analog” gauge using a small e-ink panel. Of course it won’t fool anyone who gives it a close look, but at a glance, you could certainly be forgiven for thinking it was some kind of vintage indicator. Especially with the cracked and stained Fresnel lens he put in front of it.

For this project [Hans] used a LilyGo T5, which combines an ESP32 with a 2.13 inch electronic paper display. These are presumably meant to be development boards for digital signage applications, but they occasionally show up in hacker projects since they’re so easy to work with. The board pulls data from a RD200M radon sensor over a simple UART connection, and the current reading is indicated by a “needle” that moves across a horizontal scale on the display.

On its own, it wouldn’t look very vintage. In fact, quite the opposite. But [Hans] really helped sell the look on this project by designing and 3D printing a chunky enclosure and then weathering it to make it look like it’s been kicking around since the Cold War.

If you don’t feel like faking it, we’ve seen some very impressive projects based on authentic vintage gauges. As long as you don’t mind tearing up hardware that’s likely older than you are, putting in the extra effort necessary for a convincing modification can really pay off.

[Thanks to Tarjei for the tip.]