Simple Hack Lets Smartphone Take Resin Printer Time-Lapses

With how cheap they’re getting, everyone seems to be jumping on the resin printer bandwagon. They may not be able to fully replace your trusty old FDM printer, but for certain jobs, they just can’t be beaten. Sadly though, creating those smooth time-lapse videos of your prints isn’t quite as easy to do as it is on their filament-based counterparts.

Not as easy, perhaps, but not impossible. [Fraens] found a way to make time-lapses on any resin printer, and in a wonderfully hacky way. First, you need to find a smartphone, which shouldn’t be too hard, given how often we all tend to upgrade. [Fraens] recommends replacing the standard camera app on the phone with Open Camera, to prevent it from closing during the long intervals with nothing happening. The camera is triggered by any readily available Bluetooth dongle, which is connected via a simple transistor circuit to an Arduino output. To trigger the shutter, a light-dependent resistor (LDR) is connected to one of the microcontroller’s inputs. The LDR is placed inside the bed of the resin printer — an Anycubic Photon in this case — where light from the UV panel used to cross-link the resin can fall on it. A simple bit of Arduino code triggers the Bluetooth dongle at the right moment, capturing a series of stills which are later stitched together using DaVinci Resolve.

The short video below shows the results, which look pretty good to us. There are other ways to do this, of course, but we find the simplicity of this method pleasing.

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A Flex Sensor For A Glove Controller Using An LDR

When most of us think of glove controllers, the first which comes to mind is Nintendo’s PowerGlove, which promised much more than it delivered. But the idea persists, and from time to time we see them here at Hackaday. [Gord Payne] has one with an elegant sensor solution, it detects finger movement using a light dependent resistor.

The cleverest designs are those which are the simplest, and this one eschews complex mechanisms and exotic parts for a simple piece of flexible tube. At one end is an LED and at the other the LDR, and when attached to a glove it provides a finger sensor without the fuss. The amount of light reaching the LDR from the LED decreases as the pipe is bent, and with a simple divider circuit a voltage can be read by an Arduino. You can see it in action in the video below the break, where the glove flexing controls a servo.

Perhaps this might revitalize a bit of interest in glove controllers, something we probably don’t see too many of. Those Nintendo PowerGloves do still crop up from time to time though.

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This Simple Light-Controlled Synth Has A Surprisingly Rich Sound

Audio synthesizers can range from vast racks of equipment with modules stitched together by a web of patch cords to a couple of 555s wired together in an Atari punk arrangement. This light-controlled synth comes in closer to the lower extreme of that range, but packs a sonic punch that belies its simplicity.

The project is the latest version of [lonesoulsurfer]’s “Moog Light Synthesizer,” which shares a lot of the circuitry found in his first version a couple of years ago. This one has a lot of bells and whistles, but it all starts with a PWM oscillator that contributes to the mean, growling quality of its sound. There’s also a low-pass filter that’s controlled by a couple of light-dependent resistors, which can be played by blocking them off with a fingertip. A couple of inverters form a drone oscillator that can be switched into the circuit, as well as a 555-based arpeggiator to chop things up a bit.

All those circuits, as well as support for a thirteen-key keyboard, live on one custom PCB. There’s also an off-the-shelf echo/reverb module that’s been significantly hacked to add to the richness of the sound. The custom wood and acrylic case make the whole thing look as good as it sounds.

We noted that [lonesoulsurfer]’s previous “Box of Beezz” drone synth seemed to evoke parts of the “THX Deep Note” at times; similarly, some of the sounds of this synth sound like they’d come from the soundtrack of a [Christopher Nolan] film  — check it out in the video below.

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Fytó Is Fido For Phytophiles

On the surface, most plants really aren’t all that exciting, save for maybe the Venus flytrap. Sure, you can watch them grow in the long run, but for the most part, they’re just kind of there, quietly bringing peace and cleaner air. Day by day, they hardly move at all, although if you’re one of those people who likes to get the Sim into the pool and take the ladder away, you could always play the drought game just to watch it droop and come back to life a half hour later.

Fytó the smart planter is a much more cool and far less cruel way of spicing up your plant life. The idea is to turn a plant into a pet by giving it an expressive face. Sure, plants have needs, but they communicate them more subtly than the average Earthing. By assigning animated emoji to various conditions, the plant becomes more familiar and in turn, feels more like a pet. Plus, the whole thing is just so darn cute.

Fytó runs on a Raspberry Pi 2W and has six emotions that are based on a capacitive soil moisture sensor, an LM35 temperature sensor, and an LDR module to detect light levels. If everything is copacetic, Fytó puts on a happy face, and will lick its lips after getting a drink of water. If the light is insufficient, Fytó looks sleepy; if the plant needs water, Fytó appears sweaty, red-faced, and parched. Don’t conflate this with the temperature-taking emoji, which indicates that Fytó is too hot. Finally, if the spot is too drafty and cold, Fytó looks like it’s nearly frozen. Be sure to check out the video after the break and watch Fytó work through their range of emotions.

Would you rather hear your plant complain in English? There’s a build for that.

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Four Servo Fingers Play Simon Better Than You Ever Could

Remember Simon? We sure do. Simon — as in “Simon says…” — from the leading edge of electronic games in the 1970s, which used four buttons, colored lights, and simple tones as the basis for a memory game. Players had to remember the specific sequence of lights and replay the pattern in order to advance to the next round. It was surprisingly addictive, at least for the era.

For those who never quite got into the Simon groove, fear not — the classic game has now been fully automated. While there were plenty of approaches that could have taken to interfacing to the game, [ido roseman] went with the obvious — and best, in our opinion — technique and simulated a human player’s finger presses with servo-controlled arms. Each arm carries a light-dependent resistor that registers the light coming from the key it’s poised above; the sequence of lights is sensed and recorded by an Arduino, which then drives the servo fingers’ replay attack. The fingers aren’t exactly snappy in their response, which might cause problems — if we recall correctly, Simon is somewhat picky about the speed with which the keys are pressed, at least at higher levels of play.

On the whole, we really like this one, not least for the nostalgia factor. We’ve had a lot of recreations of Simon over the years, including a Dance Dance Revolution version, but few attempts to automate it. And a crazy idea: wouldn’t it be fun to replace the replay attack with a machine learning system that figures out how to play Simon by randomly pressing keys and observing the results?

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A Transistor-less Sound Synthesizer

A synthesizer without transistors could almost be the basis of a trick question, surely without transistors it must be using a vacuum tube or similar. Not [Dr. Cockroach]’s synth though, instead of transistors it uses coupled pairs of LEDs and light-dependent resistors as its active components. Its oscillator circuit comes courtesy of [Patrick Flett], and uses a pair of LED/LDR combinations to alternately charge and discharge a capacitor. This feeds another LDR/LED pair that appears to act as a buffer to drive a bridge rectifier, with a final amplifier following it.

The result oscillates, though at frequencies in the low audio range with a cluster of harmonics thrown in. Its sound is best described as something akin to a small single-cylinder motorcycle engine at the lower frequencies, and is something we see could have all sorts of interesting possibilities.

This approach of using LDR-based active devices may be something of a dead end that could have had its day back in the 1930s, but it’s nevertheless an entertaining field to explore. It’s not the first time we’ve followed [Dr. Cockroach] at it, in the past we’ve seen the same technique applied to logic gates.

Have a listen to the synth in the video below the break. Continue reading “A Transistor-less Sound Synthesizer”

Score Big Against Boredom With Tabletop Bowling

Bowling has been around since ancient Egypt and continues to entertain people of all ages, especially once they roll out the fog machine and hit the blacklights. But why pay all that money to don used shoes and drink watered-down beer? Just build a tabletop bowling alley in your spare time and you can bowl barefoot if you want.

Those glowing pins aren’t just for looks — the LEDs underneath them are part of the scoring system. Whenever a pin is knocked out of its countersunk hole, the LED underneath is exposed and shines its light on a corresponding light-dependent resistor positioned overhead. An Arduino Uno keeps track of of the frame, ball number, and score, and displays it on an LCD.

The lane is nearly six feet long, so this is more like medium-format bowling or maybe even skee-bowling. There are probably a number of things one could use for balls, but [lainealison] is using large ball bearings. Roll past the break to see it in action, but don’t go over the line!

Can’t keep your balls out of the gutter? Build a magic ball and make all wishful leaning more meaningful as you steer it down the lane with your body.

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