A diagram showing an LED on the left, a lever-style plumbing valve in the center, and an Arduino Uno on the right.

Plumbing Valves As Heavy Duty Analog Inputs

October 24, 2022 by 36 Comments

Input devices that can handle rough and tumble environments aren’t nearly as varied as their more fragile siblings. [Alastair Aitchison] has devised a brilliant way of detecting inputs from plumbing valves that opens up another option. (YouTube) [via Arduino Blog]

While [Aitchison] could’ve run the plumbing valves with water inside and detected flow, he decided the more elegant solution would be to use photosensors and an LED to simplify the system. This avoids the added cost of a pump and flow sensors as well as the questionable proposition of mixing electronics and water. By analyzing the change in light intensity as the valve closes or opens, you can take input for a range of values or set a threshold for an on/off condition.

[Aitchison] designed these for an escape room, but we can see them being great for museums, amusement parks, or even for (train) simulators. He says one of the main reasons he picked plumbing valves was for their aesthetics. Industrial switches and arcade buttons have their place, but certainly aren’t the best fit in some situations, especially if you’re going for a period feel. Plus, since the sensor itself doesn’t have any moving parts, these analog inputs will be easy to repair should anything happen to the valve itself.

If you’re looking for more unusual inputs, check out the winners of our Odd Inputs and Peculiar Peripherals contest or this typewriter that runs Linux.

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Hackaday Prize 2022: A Spring-Driven Digital Movie Camera

September 1, 2022 by 14 Comments

These days, most of us are carrying capable smartphones with high-quality cameras. It makes shooting video so easy as to take all the fun out of it. [AIRPOCKET] decided to bring that back, by converting an old spring-driven 8mm film camera to shoot digital video.

The camera in question is a magazine-fed Bell & Howell Model 172 from the 1950s. In its original spring-driven form, it could shoot for approximately 35 seconds at a (jerky) frame rate 16 fps.

In this build, though, the film is replaced with a digital imaging system designed to fit in the same space as the original magazine. A Raspberry Pi Zero 2 was pressed into service, along with a rechargeable battery and Pi camera module. The camera is timed to synchronise with the shutter mechanism via a photosensor.

Since it uses the original optics and shutter speed, the resulting video is actually very reminiscent of the Super 8 cameras of the past. It’s an impressive way to get a retro film effect straight into a digital output format. The alternative is to just shoot on film and scan it afterwards, of course! Video after the break.

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Abacus Synthesizer Really Adds Up

June 15, 2022 by 4 Comments

The abacus has been around since antiquity, and takes similar forms over the hundreds of cultures that have embraced it. It may be one of the first devices to be considered as having a “user interface” in the modern context — at least for simple arithmetic calculations. But using an abacus as the UI for a music synthesizer seems like something entirely new.

Part art concept project and part musical instrument, the “Abacusynth” by [Elias Jarzombek] is a way to bring a more visual and tactile experience to controlling a synth, as opposed to the usual knobs and switches. The control portion of the synth consists of four horizontal rods spanning two plywood uprights. Each rod corresponds to a voice of the polyphonic synth, and holds a lozenge-shaped spinner mounted on a low-friction bearing. Each spinner can be moved left and right on its rod, which controls the presence of that voice; spinning the slotted knob controls the modulation of the channel via photosensors in the uprights. Each rod has a knob on one side that activates an encoder to control each voice’s waveform and its harmonics.

In use, the synthesizer is a nice blend of electronic music and kinetic sculpture. The knobs seem to spin forever, so Abacusynth combines a little of the fidget spinner experience with the exploration of new sounds from the built-in speaker. The synth also has a MIDI interface, so it works and plays well with other instruments. The video below shows the hardware version of Abacusynth in action; there’s also a web-based emulation to try before you build.

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Automate Parts Kitting With This Innovative SMD Tape Slicer

June 7, 2022 by 5 Comments

Nobody likes a tedious manual job prone to repetitive stress injury, and such tasks rightly inspire an automated solution. This automatic SMD tape cutter is a good example of automating such a chore, while leaving plenty of room for further development.

We’re used to seeing such tactical automation projects from [Mr Innovative], each of which centers on an oddly specific task. In this case, the task involves cutting a strip containing a specific number of SMD resistors from a reel, perhaps for assembling kits of parts. The mechanism is simple: a stepper motor with a rubber friction wheel to drive the tape, and a nasty-looking guillotine to cut the tape. The cutter is particularly interesting, using as it does a short length of linear bearing to carry a holder for a razor blade that’s mounted perpendicular to the SMD tape. The holder is mounted to a small motor via a crank, and when the proper number of parts have been fed out, the motor rotates one revolution, driving the angled blade quickly down and then back up. This results in a shearing cut rather than the clipping action seen in this automated wire cutter, also by [Mr Innovative].

Curiously, there seems to be no feedback mechanism to actually measure how many resistors have been dispensed. We assume [Mr Innovative] is just counting steps, but it seems easy enough to integrate a photosensor to count the number of drive sprocket holes in the tape. It also seems like a few simple changes would allow this machine to accommodate SMD tapes of different sizes, making it generally useful for SMD kitting. It’s still pretty cool as a tactical project, though, and does a great job inspiring future improvements.

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About As Cold As It Gets: The Webb Telescope’s Cryocooler

May 5, 2022 by 26 Comments

If you were asked to name the coldest spot in the solar system, chances are pretty good you’d think it would be somewhere as far as possible from the ultimate source of all the system’s energy — the Sun. It stands to reason that the further away you get from something hot, the more the heat spreads out. And so Pluto, planet or not, might be a good guess for the record low temperature.

But, for as cold as Pluto gets — down to 40 Kelvin — there’s a place that much, much colder than that, and paradoxically, much closer to home. In fact, it’s only about a million miles away, and right now, sitting at a mere 6 Kelvin, the chunk of silicon at the focal plane of one of the main instruments aboard the James Webb Space telescope makes the surface of Pluto look downright balmy.

The depth of cold on Webb is all the more amazing given that mere meters away, the temperature is a sizzling 324 K (123 F, 51 C). The hows and whys of Webb’s cooling systems are chock full of interesting engineering tidbits and worth an in-depth look as the world’s newest space telescope gears up for observations.

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Small sensor built into audio jack, held in tweezers

Measuring LED Flicker, With Phototransistor And Audio App

September 1, 2021 by 26 Comments

No one likes a flickering light source, but lighting is often dependent on the quality of a building’s main AC power. Light intensity has a close relation to the supply voltage, but bulb type plays a role as well. Incandescent and fluorescent bulbs do not instantly cease emitting the instant power is removed, allowing their output to “coast” somewhat to mask power supply inconsistencies, but LED bulbs can be a different story. LED light output has very little inertia to it, and the quality of both the main AC supply and the bulb’s AC rectifier and filtering will play a big role in the stability of an LED bulb’s output.

Mobile phone spectrum analyzer pointed at light source
The DIY photosensor takes the place of the microphone input.

[Tweepy] wanted to measure and quantify this effect, and found a way to do so with an NPN phototransistor, a resistor, and a 3.5 mm audio plug. The phototransistor and resistor take the place of a microphone plugged into the audio jack of an Android mobile phone, which is running an audio oscilloscope and spectrum analyzer app. The app is meant to work with an audio signal, but it works just as well with [Tweepy]’s DIY photosensor.

Results are simple to interpret; the smoother and fewer the peaks, the better. [Tweepy] did some testing with different lighting solutions and found that the best performer was, perhaps unsurprisingly, a lighting panel intended for photography. The worst performer was an ultra-cheap LED bulb. Not bad for a simple DIY sensor and an existing mobile phone app intended for audio.

Want a closer look at what goes into different LED bulbs and how they tick? We have you covered. Not all LED bulbs are the same, either. Some are stripped to the bone and others are stuffed with unexpected goodness.

This Arduino Isn’t Color Blind

July 4, 2021 by 5 Comments

You can sense a lot of things with the right sensor, and [Nikhil Nailwal] is here to show us how to sense colors using a TCS230. The project is a simple demo. It displays the color and lights up an LED to correspond to the detected color.

If you haven’t seen the TCS230 before, it is a chip with an array of photosensors, for different light wavelengths. The controlling chip — an Arduino, in this case — can read the intensity of the selected color.

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