Cheap Dual Mirror Laser Projector

[Stanley] wanted to make a laser projector but all he could find online were one’s using expensive galvanometer scanners. So instead he came up with his own solution that is to be admired for its simplicity and its adaptation of what he could find.

At its heart is an Arduino Uno and an Adafruit Motor Shield v2. The green laser is turned on and off by the Arduino through a transistor. But the part that makes this really a fun machine to watch at work are the two stepper motors and two mirrors that reflect the laser in the X and Y directions. The mirrors are rectangles cut from a hard disk platter, which if you’ve ever seen one, is very reflective. The servos tilt the mirrors at high speed, fast enough to make the resulting projection on the wall appear almost a solid shape, depending on the image.

He’s even written a Windows application (in C#) for remotely controlling the projector through bluetooth. From its interface you can select from around sixteen predefined shapes, including a what looks like a cat head, a heart, a person and various geometric objects and line configurations.

There is a sort of curving of the lines wherever the image consists of two lines forming an angle, as if the steppers are having trouble with momentum, but that’s probably to be expected given that they’re steppers controlling relatively large mirrors. Or maybe it’s due to twist in the connection between motor shaft and mirror? Check out the video after the break and let us know what you think.

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Laser Pointer Clock Makes Timekeeping A Drawn-Out Affair

Designing a unique clock to flex your technical skills can be a rewarding experience and result in an admirable showpiece for your home. [Andres Robam] saw an opportunity to make a laser-pointer clock that draws the current time onto a glow-in-the-dark sticker.

A pair of stepper motors tilt and pan the laser’s mount — designed in SolidWorks and 3D printed. There was an issue with the motor’s shaft having some slack in it — enough to affect the accuracy of the laser. [Andres] cleverly solved the issue by using a pen’s spring to generate enough tension in the system, correcting it. A NODEmcu v2 is the brains of the clock — chosen because of its built-in WiFi capacity and compatibility with the Arduino IDE — and a 5mW laser sketches the time onto the sticker.

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Litter Basket Automation

Sometimes the technology part of a project isn’t the hard part. It is having an idea for something both useful and doable. Sure, a robot butler that would do your cleaning and laundry would be useful, but might be out of reach for most of us. On the other hand, there’s only so many use cases for another blinking LED.

[Martinhui] knows how to use an ultrasonic sensor with an Arduino. Driving a motor isn’t that hard, either. The question is: what do you do with that? [Martin’s] answer: Automate a trash can. You can see a video of the result, below.

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Scissors Make Great Automatic Cable Cutters

The team at [2PrintBeta] required a bunch of cables, heat shrink, and braid to be cut for their customers. They looked into an industrial cable cutter, but decided the price was a little too high, so they decided to make their own. They had a bunch of ideas for cutting: Using a razor blade?  Or a Dremel with a cutting wheel? What they came up with was a DIY cable cutter that uses a pair of scissors, a pair of stepper motors, a pair of 3D printed wheels and an Arduino.

The first thing the team had to do was to mount the scissors so they would cut reliably. One of the stepper motors was attached to a drive wheel that had a bolt mounted on it. This went through one of the scissors’ handles, the other handle was held in place on the machine using screws. The second stepper motor was used to rotate the wheels that drives the cable through to the correct length. [2PrintBeta] used a BAM&DICE shield and two DICE-STK stepper motor drivers on an Arduino Mega to control the cutter.

The [2PrintBeta] team are pretty good at doing things themselves, as we’ve seen previously with their DIY plastic bender. And again, with this automatic cable cutter, they’ve seen a need and resolved it using the things at their disposal and some DIY ingenuity.

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Giant-Scale Physical Pong

At first, we thought we were having deja vu, but then we saw this video embedded below. [Thijs Eerens] is a creative technologist (dare we say, a “hacker”?) who builds giant-scale games for a living. For the Lowlands festival in the Netherlands, he contributed to the build of a huge Pong game that looks as big as a cinema screen.

The paddles appear to be controlled by pulling ropes, and the “ball” is driven around on a system of wires and stepper motors. Code running in the background tracks the player paddles, drives the ball, and keeps score. From the video, there seem to be sound effects involved. It looks like a lot of fun.

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Trash-heap Water Wheel Recharges iPhone in the Woods

We’ve all been there – hiking in the woods with a dead phone battery. No GPS, no way to Tweet that selfie from some hill with a great vista. It’s a disaster! But not if you have access to a little trailside junk and have the ingenuity to build this field-expedient water wheel generator to recharge your phone.

OK, it’s a stretch to imagine finding all the things needed for [Thomas Kim]’s hack. We’re only guessing at the BOM – the video below has little commentary, so what you see is what you get – but it looks like a garbage can at the trailhead might at least yield the materials needed to build the turbine. Water bottle bottoms and a couple of plastic picnic plates form the Pelton-like impeller, the frame looks like an old drying rack, and the axle appears to be a campfire skewer. But you might have a hard time finding the electrical side of the build, which consists of a stepper motor, a rectifier, and an electrolytic cap. Then again, you could get lucky and find a cast-off printer by the side of the road. No matter how he got the materials, it’s pretty cool to see an iPhone recharging next to a babbling brook in the woods.

Looking for a little more oomph from your trash-heap hydroelectric turbine? Maybe you need to look at this washing machine power plant build.

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Simple Clock is Great Stepper Motor Project

You’d think that we’ve posted every possible clock here at Hackaday. It turns out that we haven’t. But we have seen enough that we’ve started to categorize clock builds in our minds. There are the accuracy clocks which strive to get every microsecond just right, the bizzaro clocks that aim for most unique mechanism, and then there are “hello world” clocks that make a great introduction to building stuff.

Today, we’re looking at a nice “hello world” clock. [electronics for everyone]’s build uses a stepper motor and a large labelled wheel that rotates relative to a fixed pointer. Roll the wheel, and the time changes. It looks tidy, it’s cyclical by design, and it’s a no-stress way to get your feet wet driving stepper motors. And it comes with a video, embedded below.

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