Digital Replica Of Antique Weather Monitoring Instrument

Computers and digital sensors have allowed for the collection and aggregation of data barely possible to imagine to anyone in the instrumentation scene even sixty years ago. Before that, things like weather stations, seismometers, level sensors, and basically any other way of gathering real data about the world would have been performed with an analog device recording the information on some sort of spool of paper. This was much more tedious but the one thing going for these types of devices was their aesthetic. [mircemk] is back to bring some of that design inspiration to a digital barometric display.

The barometer is based around an Arduino Arduino Nano and a relatively large I2C display to display the captured data. It also uses a BME 280 pressure sensor board, but the technical details of this project are not the focal point here. Instead, [mircemk] has put his effort in recreating the old analog barographs, which display barometric data on a spool of paper over time, on the I2C display. As the device measures atmospheric pressure, it adds a bar to the graph, displaying the data over time much as the old analog device would have.

We’ve discussed plenty of times around here that old analog meters and instrumentation like this recreation of a VU meter are an excellent way of getting a more antique aesthetic than is typically offered by digital replacements. Adding in a little bit of style to a project like this can go a long way, or you can simply restore the original antique instead.

How To Build Jenny’s Budget Mixing Desk

Jenny did an Ask Hackaday article earlier this month, all about the quest for a cheap computer-based audio mixer. The first attempt didn’t go so well, with a problem that many of us are familiar with: Linux applications really doesn’t like using multiple audio devices at the same time. Jenny ran into this issue, and didn’t come across a way to merge the soundcards in a single application.

I’ve fought this problem for a while, probably 10 years now. My first collision with this was an attempt to record a piano with three mics, using a couple different USB pre-amps. And of course, just like Jenny, I was quickly frustrated by the problem that my recording software would only see one interface at a time. The easy solution is to buy an interface with more channels. The Tascam US-4x4HR is a great four channel input/output audio interface, and the Behringer U-PHORIA line goes all the way up to eight mic pre-amps, expandable to 16 with a second DAC that can send audio over ADAT. But those are semi-pro interfaces, with price tags to match.

But what about Jenny’s idea, of cobbling multiple super cheap interfaces together? Well yes, that’s possible too. I’ll show you how, but first, let’s talk about how we’re going to control this software mixer monster. Yes, you can just use a mouse or keyboard, but the challenge was to build a mixing desk, and to me, that means physical faders and mute buttons. Now, there are pre-built solutions, with the Behringer X-touch being a popular solution. But again, we’re way above the price-point Jenny set for this problem. So, let’s do what we do best here at Hackaday, and build our own. Continue reading “How To Build Jenny’s Budget Mixing Desk”

Connecting A Keyboard To A Vintage PC-XT, The Hard Way

We’re not sure if there’s any single characteristic that qualifies someone as a hacker. After all, we’re a pretty eclectic bunch, with skills that range all over the map, and what one person feels is trivial, others would look upon as black magic. But there’s one thing we’re sure of: if you find yourself reading the original POST code for the PC-XT motherboard just to get a keyboard working, you’re pretty much our kind of people.

That was the position [Anders Nielsen] found himself in as work progresses on his “PC-XT from Scratch” project, which seeks to build a working mid-80s vintage IBM Model 5160 using as many period-correct parts as possible. The first installment of the series featured the delicate process of bringing the motherboard up, lest the magic smoke was released. After seeing some life out of the old board, [Anders] needed a little IO, specifically video and keyboard. The video side of the equation was relatively trivial, with an early-90s VGA card from eBay — not exactly period correct, but good enough to get something to display. Continue reading “Connecting A Keyboard To A Vintage PC-XT, The Hard Way”

A vintage film camera with a bright light emitting diode shining through it, next to electronic equipment to measure the shutter speed

Clock Your Camera With This Shutter Speed Tester

Camera shutter speed is an essential adjustment in photography – along with the aperture, the shutter moderates the amount of light entering the camera. Older cameras (and some newer ones) use mechanical shutters that creep out-of-spec over the years, so [Dean Segovis] built a handy shutter speed tester.

With just a handful of basic components, this project is a great one for beginners to sink their teeth into. The tester is based around a photoresistor that measures light from another source (a flashlight) that travels through the camera body. When the shutter on the camera is released, the shutter speed can be measured and displayed on the OLED screen. An Arduino naturally handles all the computational duties. The whole thing can be easily assembled on a breadboard in just a couple of minutes.

The original project by [hiroshootsfilm] is over on Project Hub, however [Dean] takes a deeper dive with some code troubleshooting, as well as trying out a variety of old film cameras with the breadboard tester. His testing revealed that the photoresistor was better able to detect shutter speed when the camera lens was removed, which is a hot tip for anyone else that wants to try this.

While it’s not surprising that these older cameras are having trouble with their mechanical shutters, this little tester would be an invaluable tool when it comes time to start tweaking shutter mechanisms. If this project has brought out the shutterbug in you, make sure to check out this brain transplant for a Polaroid 100-series Packfilm camera that we covered way back in 2011.

Continue reading “Clock Your Camera With This Shutter Speed Tester”

Arduino Does SDI Video With FPGA Help

If you are running video around your home theater, you probably use HDMI. If you are running it in a professional studio, however, you are probably using SDI, Serial Digital Interface. [Chris Brown] looks at SDI and shows a cheap SDI signal generator for an Arduino.

On the face of it, SDI isn’t that hard. In fact, [Chris] calls it “dead simple.” The problem is the bit rate which can be as high as 1.485 Gbps for the HD-SDI standard. Even for a super fast processor, this is a bit much, so [Chris] turned to the Arduino MKR Vidor 4000. Why? Because it has an FPGA onboard. Alas, the FPGA can’t do more than about 200 MHz, but that’s fast enough to drive an external Semtech GS296t2 serializer which is made to drive SDI signals.

The resulting project contains the Arduino, the serializer, a custom PCB, and both FPGA and microcontroller code. While the total cost of the project was a little under $200, that’s still better than the $350 to $2000 for a commercial SDI signal generator.

If you want to play along, the files are out on GitHub. We used the Vidor back in 2018 when it first came out. If you need a quick start on FPGAs, there’s always our boot camp.

Mechanical Keyboard Is Also A Mouse

The mechanical keyboard community is a vibrant, if not fanatical, group of enthusiasts determined to find as many possible ways of assembling, building, and using as many high-quality keyboards as possible. With so many dedicated participants, most things that can be done with a keyboard already have been done. So when something as unique as this split keyboard that also doubles as a mouse pops up, we take notice.

The keyboard is a custom build from [Taliyah Huang] which uses a pair of Arduinos, one in each half of the keyboard, to communicate key and mouse information to a third Arduino which is plugged in to her laptop. The right-hand half of the keyboard also includes the circuitry from an optical mouse, which gets powered up when the caps lock button is held down. When activated, this allows the keyboard to be used as a mouse directly. It also includes support for most Mac gestures as well, making it just as useful as a trackpad.

While there were some problems with the design, including being slightly too tall to be ergonomic and taking nearly 24 hours of soldering to complete, the prototype device is an interesting one especially since it allows for full control of a computer without needing a dedicated mouse. For other unique mechanical keyboard concepts, we recently featured this build which takes design and functionality cues from the Commodore 64.

Continue reading “Mechanical Keyboard Is Also A Mouse”

An Atomic Pendulum Clock Accurate Enough For CERN

That big grandfather clock in the library might be an impressive piece of mechanical ingenuity, and an even better example of fine cabinetry, but we’d expect that the accuracy of a pendulum timepiece would be limited to a sizable fraction of a minute per day. Unless, of course, you work at CERN and built  “the most accurate pendulum clock on the planet.”

While we’re in no position to judge [Daniel Valuch]’s claim, we’re certainly inclined to believe him, mainly because the 1950s-era Czechoslovakian pendulum clock his project was based on, the Elektročas HH3, was built specifically as a master clock for labs, power plants, and broadcast use. The pendulum of this mid-century beauty is made of the alloy invar, selected for its exceptionally low coefficient of thermal expansion. This ensures the pendulum doesn’t change length with temperature, but it still only brings the clock into the 0.1 second/day range.

Clearly that’s not good enough for a clock at CERN, the European Laboratory for Nuclear Research, where [Daniel] works as an RF engineer. With access to a 10-MHz timebase from a cesium fountain atomic clock — no less a clock than the one that’s used to define the SI second, by the way — [Daniel] looked for ways to sync the clock up to it. Now, we know what you’re thinking — he must have used some kind of PLL to give an electromagnetic “kick” to the bob to trim the pendulum’s period. Good guess on the PLL, but the trimming method is a little cruder — [Daniel] uses a stepper motor attached to the clock’s frame to pay out or retract a length of fine chain into a cardboard dish attached to the pendulum’s rod. The change in mass changes the pendulum’s center of gravity, which changes its effective length, and allows the clock to be tuned a couple of seconds per day.

It seems like [Daniel] is claiming that his chain-corrected clock won’t drift more than a second from the cesium clock for 158 million years. Again, we’ll take his word for it, but it’s a wonderfully ad hoc approach to tuning the clock, and we appreciate its simplicity.