A Big Computer Needs A Big Keyboard

September 19, 2020 by Al Williams 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 Mike Szczys 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 Tom Nardi 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.]

Rapid Charging Supercapacitors

September 16, 2020 by Bryan Cockfield 40 Comments

Battery technology is the talk of the town right now, as it’s the main bottleneck holding up progress on many facets of renewable energy. There are other technologies available for energy storage, though, and while they might seem like drop-in replacements for batteries they can have some peculiar behaviors. Supercapacitors, for example, have a completely different set of requirements for charging compared to batteries, and behave in peculiar ways compared to batteries.

This project from [sciencedude1990] shows off some of the quirks of supercapacitors by showing one method of rapidly charging one. One of the most critical differences between batteries and supercapacitors is that supercapacitors’ charge state can be easily related to voltage, and they will discharge effectively all the way to zero volts without damage. This behavior has to be accounted for in the charging circuit. The charging circuit here uses an ATtiny13A and a MP18021 half-bridge gate driver to charge the capacitor, and also is programmed in a way that allows for three steps for charging the capacitor. This helps mitigate the its peculiar behavior compared to a battery, and also allows the 450 farad capacitor to charge from 0.7V to 2.8V in about three minutes.

If you haven’t used a supercapacitor like this in place of a lithium battery, it’s definitely worth trying out in some situations. Capacitors tolerate temperature extremes better than batteries, and provided you have good DC regulation can often provide power more reliably than batteries in some situations. You can also combine supercapacitors with batteries to get the benefits of both types of energy storage devices.

Deep-Sleep Problems Lead To Forensic Investigation Of Troublesome Chip

September 15, 2020 by Dan Maloney 53 Comments

When you buy a chip, how can you be sure you’re getting what you paid for? After all, it’s just a black fleck of plastic with some leads sticking out of it, and a few laser-etched markings on it that attest to what lies within. All of that’s straightforward to fake, of course, and it’s pretty easy to tell if you’ve got a defective chip once you try it out in a circuit.

But what about off-brand chips? Those chips might be functionally similar, but still off-spec in some critical way. That was the case for [Kevin Darrah] which led to his forensic analysis of potentially counterfeit MCU chips. [Kevin] noticed that one of his ATMega328 projects was consuming way too much power in deep sleep mode — about two orders of magnitude too much. The first video below shows his initial investigation and characterization of the problem, including removal of the questionable chip from the dev board it was on and putting it onto a breakout board that should draw less than a microamp in deep sleep. Showing that it drew 100 μA instead sealed the deal — something was up with the chip.

[Kevin] then sent the potentially bogus chip off to a lab for a full forensic analysis, because of course there are companies that do this for a living. The second video below shows the external inspection, which revealed nothing conclusive, followed by an X-ray analysis. That revealed enough weirdness to warrant destructive testing, which showed the sorry truth — the die in the suspect unit was vastly different from the Atmel chip’s die.

It’s hard to say that this chip is a counterfeit; after all, Atmel may have some sort of contract with another foundry to produce MCUs. But it’s clearly an issue to keep in mind when buying bargain-basement chips, especially ones that test functionally almost-sorta in-spec. Caveat emptor.

Counterfeit parts are depressingly common, and are a subject we’ve touched on many times before. If you’d like to know more, start with a guide.

Continue reading “Deep-Sleep Problems Lead To Forensic Investigation Of Troublesome Chip” →

Putting The Firmware In Your Firmware

September 15, 2020 by Kerry Scharfglass 12 Comments

Performing over-the-air updates of devices in the field can be a tricky business. Reliability and recovery is of course key, but even getting the right bits to the right storage sectors can be a challenge. Recently I’ve been working on a project which called for the design of a new pathway to update some small microcontrollers which were decidedly inconvenient.

There are many pieces to a project like this; a bootloader to perform the actual updating, a robust communication protocol, recovery pathways, a file transfer mechanism, and more. What made these micros particularly inconvenient was that they weren’t network-connected themselves, but required a hop through another intermediate controller, which itself was also not connected to the network. Predictably, the otherwise simple “file transfer” step quickly ballooned out into a complex onion of tasks to complete before the rest of the project could continue. As they say, it’s micros all the way down.

Continue reading “Putting The Firmware In Your Firmware” →

Mirrored Music Machine Reflects Circadian Rhythms

September 15, 2020 by Kristina Panos 8 Comments

Interactive artist [Daric Gill] wrote in to share the incredible electronic sculpture he’s been working on for the past year. It’s called the Circadian Machine, and it’s a sensor-enabled mindfulness music-and-lights affair that plays a variety of original compositions based on the time of day and the circle of fifths. This machine performs some steady actions like playing chimes at the top of each hour, and a special sequence at solar noon.

This cyberpunk-esque truncated hexagonal bi-pyramid first geolocates itself, and then learns the times for local sunrise and sunset. A music module made of a Feather M4 Express and a Music Maker FeatherWing fetches astronomical data and controls the lights, speakers, and a couple of motion sensors that, when tripped, will change the lights and sounds on the fly. A separate Feather Huzzah and DS3231 RTC handle the WiFi negotiation and keep track of the time.

On top of the hourly lights and sound, the Circadian Machine does something pretty interesting: it performs another set of actions based on sunrise and sunset, basically cramming an entire day’s worth of actions between the two events, which seems like a salute to what humans do each day. Check out the build notes and walk-through video after the break, then stick around for the full build video.

The internet is rife with information just begging to be turned into art. For instance, there are enough unsecured CCTV cameras around the world with primo vantage points that you can watch a different sunrise and sunset every hour of every day.

Continue reading “Mirrored Music Machine Reflects Circadian Rhythms” →