Misc Hacks

4196 Articles

[Ben Krasnow] Looks Inside Film Camera Date Stamping

October 15, 2019 by 6 Comments

Honestly, we never wondered how those old film cameras used to put the date stamp in the lower right-hand corner of the frame. Luckily, [Ben Krasnow] does not suffer from this deplorable lack of curiosity, and his video teardown of a date-stamping film camera back (embedded below) not only answers the question, but provides a useful lesson in value engineering.

For the likely fair fraction of the audience who has never taken a photo on film before, cheap 35-mm cameras were once a big thing. They were really all one had for family snapshots and the like unless you wanted to invest in single-lens reflex cameras and all the lenses and accessories. They were miles better than earlier cartridge cameras like the 110 or – shudder – Disc film, and the cameras started getting some neat electronic features too. One was the little red-orange date stamp, which from the color we – and [Ben] assumed was some sort of LED pressed up against the film, but it ends up being much cooler than that.

Digging into the back of an old camera, [Ben] found that there’s actually a tiny projector that uses a mirror to fold the optical path between the film and a grain-of-wheat incandescent bulb. An LCD filter sits in the optical path, but because it’s not exactly on the plane of the film, it actually has to project the image onto the film. The incandescent bulb acts as a point source and the mirror makes the optical path long enough that the date stamp image appears sharp on the film. It’s cheap, readily adapted to other cameras, and reliable.

Teardowns like this aren’t fodder for [Ben]’s usual video fare, which tends more toward homemade CT scanners and Apollo-grade electroluminescent displays, but this was informative and interesting, too.

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Robotic Laundry Line Reels You In

October 12, 2019 by 22 Comments

It may not be a laundry-folding robot, but this robotic launders line build by [Radical Brad Graham] is pretty neat. He has a 75-foot hanging laundry line from his house to a woodshed, and decided to roboticize it using some bits that were lying around. The result is a simple build that adds push-button control to pull the line back and forward, making it easier to hang everything out to dry. It’s a simple build, but [Brad] did a great job of documenting what he did and why, from mounting the posts that support the line to wiring up the control buttons.

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2D-Scanner Records Surfboard Profiles For Posterity

October 6, 2019 by 5 Comments

[Ryan Schenk] had a problem: he built the perfect surfboard. Normally that wouldn’t present a problem, but in this case, it did because [Ryan] had no idea how he carved the gentle curves on the bottom of the board. So he built this homebrew 2D-scanner to make the job of replicating his hand-carved board a bit easier.

Dubbed the Scanbot 69420 – interpretation of the number is left as an exercise for the reader, my dude – the scanner is pretty simple. It’s just an old mouse carrying a digital dial indicator from Harbor Freight. The mouse was gutted, with even the original ball replaced by an RC plane wheel. The optical encoder and buttons were hooked to an Arduino, as was the serial output of the dial indicator. The Arduino consolidates the data from both sensors and sends a stream of X- and Z-axis coordinates up the USB cable as the rig slides across the board on a straightedge. On the PC side, a Node.js program turns the raw data into a vector drawing that represents the profile of the board at that point. Curves are captured at various points along the length of the board, resulting in a series of curves that can be used to replicate the board.

Yes, this could have been done with a straightedge, a ruler, and a pencil and paper – or perhaps with a hacked set of calipers – but that wouldn’t be nearly as much fun. And we can certainly see applications for this far beyond the surfboard shop.

DIY Clapper Lets You Pick Your Components

October 6, 2019 by 4 Comments

One thing that always means the end of the year is close is the reappearance of TV ads for “The Clapper.” After all, who needs home automation when you can clap on and clap off? While we’re partial to our usual home automation solutions, [Utsource123] shows us that building a clapper can be a fun and easy project using several similar circuits. One with a few transistors and another one with a 555 because, after all, what can’t a 555 do?

Of course, these circuits usually have a microphone. We were trying to think of how you could make a sound-sensitive element out of common parts. After all, you don’t care about the fidelity of the microphone pickup, just that it hears a loud noise. The circuits are about what you’d expect. The transistor version uses one to amplify the microphone and another to switch on the LED. You’d need a bit more to trigger a relay. The 555 uses an even simpler preamp transistor as a trigger.

While we aren’t bowled over with the idea of a clapper, we imagine these circuits aren’t far removed from the ones you buy in stores. For about $16 you also get enough switching to handle a simple AC load, though. Maybe Alexa and Google should allow making clapping a wake up word?

This is sure simpler than the last clapper clone we saw. Then there’s the deluxe DIY version.

Upgrades Give Crazy Cart XL A Few More X’s

October 6, 2019 by 4 Comments

Why should kids have all the newfangled fun? They shouldn’t! Quarter-life crises are on the rise, and those who can are spoiling their inner child with adult-sized Heelys and electric Mario Karts that can drift. [austiwawa] finally got his hands on a used Crazy Cart XL, and while it’s incredibly fun, the puny 500W motor doesn’t quite satisfy his need for speed. A 3x power upgrade should do the trick.

The new 1600W motor is considerably bigger, so [austiwawa] had to grind off part of the front fork to make it fit. He designed a replacement motor support plate and had it cut from quarter-inch steel. Of course, you can’t just drop in a crazy new motor like that and go — you need a battery and controller to match. A couple of attempts and a new spot welder later, [austiwawa] built a 48V battery pack out of 18650s. The cart actually weighs less now, which should make the ride extra insane. Put a helmet on FFS and drift past the break to the build video and demo. Then watch him tear up the mean streets parking lots of Canada and take the kart off some sweet jumps.

We love a good fun-mobile around here, be it scratch-built or hacked OEM. This wasn’t even [austiwawa]’s first rodeo — check out his water-cooled electric drift trike.

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This Lightning Detector Is Remarkably Sensitive

October 3, 2019 by 17 Comments

Lightning strikes are quite high energy events, and release plenty of radio frequency energy when they go off in the atmosphere. This makes them easy to detect, and the magnitude of the energy release means it can be done at impressive range. [Jay] decided to build a device of his very own, and was impressed at its detection performance.

The device is a simple but effective design. An antenna is used to capture RF signals, and these are then amplified through a single transistor stage. This is connected to a basic transistor flasher circuit, which is biased to only flash when tipped over the edge by an incoming signal. After building the circuit, [Jay] noticed that the device wasn’t just picking up signals from lightning, but also those from many other smaller discharges. The device was able to detect a shock from wearing socks on a wood floor, as well as discharges from a Van de Graff generator and even just from getting out of a chair!

Lightning detectors have been around for a long time now; we’ve seen others grace these pages before. Video after the break.

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Weather Alert Lamp Keeps An Eye On What’s Brewing

October 2, 2019 by 2 Comments

Whether you’re getting ready for work in the morning, or heading out on a camping trip in the woods, it’s nice to know what to expect when the weather rolls over the horizon. To keep abreast of things, [natethecoder] built a lamp system to stay across weather alerts.

A Raspberry Pi 3 acts as the heart of the system, with Node Red responsible for running the show. Querying the web every 5 minutes for updated weather data, it keeps track of weather alerts, as well as incoming snowfall. For a basic weather watch, a yellow lamp is lit, while there’s a red lamp for more serious warnings. A Christmas decoration serves as the indicator for snow. The lamps are all controlled by mains-rated solid state relays, making it easy to swap out the lamps for other devices if so desired down the track. There’s also a lamp test subroutine that fires on startup to ensure everything is working correctly.

It’s a handy way to get your weather info at a glance, and would prove useful to anyone living in a storm-prone area. For something more portable, consider this umbrella that tells you the weather.