Reddit user “jeff122885” has come up with a fairly simple yet clever coin-operated ticketing system for his Wi-Fi network. The setup consists of a Ch-926 multi-coin acceptor, a MikroTik Groove, and an Arduino Uno with a microSD card module. The unique password for the hotspot is stored in the SD card and read by the Arduino.

Once the coins are deposited, the voucher code, Wi-Fi name, duration, cost, and instructions on how to connect are printed onto a receipt. You can see it all in action below!

Hi again dear LMR members!

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Hi again dear LMR members!

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Inspired by the one seen in Honey, I Shrunk The Kids, Blake Hodgson has built a remote-controlled lawn mower of his own dubbed ”Lawn Da Vinci.”

The robotic machine’s frame is made from angle iron and steel, while its wheels and motors were taken from a mobility scooter. Power is supplied by a pair of 12V car batteries wired in series, and it’s driven across the yard with an RC airplane remote.

The Lawn Da Vinci has two Arduino Pro Minis and a Raspberry Pi for a brain–one Arduino is used for the motors and RC signal, the other for the kill switches. Meanwhile, the Raspberry Pi is tasked with streaming video from an attached webcam to his phone.

To improve reliability and reduce complexity, the motor driver now gets its signal directly from the RC receiver once it goes through the two relays controlled by the Arduino, which is always looking for a good signal. The Arduino and Raspberry Pi are powered off of a disassembled car cigarette lighter USB charger which takes the 12v of the batteries down to a clean 5v. I originally had it powered off of the Sabertooth but have better reliability this way. There are many ways to kill the motors.  You can turn the remote off, push the trainer button, left with the right joystick, or push a button separate key fob and all of these will kill it.

Rather not to push a mower around all summer long? Check out Hodgson’s entire project–complete with its code–on his blog here, or read more on Hackaday.

Motion control photography allows for stunning imagery, although commercial robotic MoCo rigs are hardly affordable. But what is money? Scratch-built from what used to be mechatronic junk and a hacked Canon EF-S lens, [Howard’s] DIY motion control camera rig produces cinematic footage that just blows us away.

[Howard] started this project about a year ago by carrying out some targeted experiments. These would not only assess the suitability of components he gathered together from all directions, but also his own capacity in picking up enough knowledge on mechatronics to make the whole thing work. After making  himself accustomed to stepper motors, Teensies and Arduinos, he converted an old moving-head disco light into a pan and tilt mount for the camera. A linear axis was added, and with more degrees of freedom, more sophisticated means of control became necessary.

Using the Swift programming language, [Howard] wrote a host program automatically detects the numerous stepper and servo motor based axis and streams the position data to their individual Teensy LC based controllers. To the professional motion graphics artist , these shots aren’t just nice and steady footage: The real magic happens when he starts adding perfectly matched layers of CGI. Therefore, he also wrote some Python scripts that allow him to manually control his MoCo rig from a virtual rig in Blender, and also export camera trajectories directly from his 3D scenes.

On top of the 4-axis camera mount and a rotary stage, [Howard] also needed to find an electronic follow-focus mechanism to keep the now moving objects in focus. Since the Canon EF-S protocol had already been reverse engineered, he decided to tap into the SPI control bus between the camera and the lens to make use of its internal ring motor. Although the piezo motors in autofocus lenses aren’t actually built for absolute positioning, a series of tests revealed that a Canon EF-S 17-55mm IS USM lens can be refocused a few hundred times and still return to its starting position close enough. The caveat: [Howard] had to hack open the £600 lens and drill holes in it. In retrospect, he tells us, it’s a miracle that his wife didn’t leave him during the project.

After several iterations of mechanical improvements, the motion control rig is now finished, and the first clips have already been recorded and edited. They’re stunning. Only the 6-axis robot arm hiding in [Howard’s] basement tells us that he just warming up for the real game. Enjoy the video below, but don’t miss out on the full 3-part video documentary on how this project came to be.

Let’s face it, there’s something magical about split flap displays. Common throughout older airports and train stations, the electromechanical devices are used to show changeable alphanumeric text (e.g. arrival and departures), fixed graphics, or in Jonathan Odom’s case, Internet slang.

With three-letter abbreviations like BRB, LOL, OMG and SMH commonplace in today’s smartphone and online conversations, the Maker decided to bring text and animation back to its mechanical roots with his own split flap display. As you can see in the video below, an arcade button under each frame enables him to cycle through all 26 letters to spell out his thoughts in acronym form, while a fourth frame reveals an animation of the very first cat video (by Eadweard Muybridge).

Structurally, the DIY gadget consists of 3D-printed parts, laser-cut acrylic for the tongue, flaps, brackets, wheels and spars, and plywood for the base. Everything is assembled by hand using screws and nuts. In terms of electronics, an Arduino Uno and Adafruit Motor Shield control a set of servo motors.

The configuration I built has four modules, but you could build as many as you want and connect them. The Arduino motor shield has 16 channels, so if you want more than than that you’ll have to find another means of controlling the rotation.

Want one for your desk? You can find all the necessary files and code on its project page, and see the final product in action below!

For our throwback project of the week, we stumbled upon a YouTube video that dates all the way back to 2012. And while the viral clip itself (which has over 1.4M views) may be a few years old, the problem it solves is timeless.

Unfortunately, you don’t get to choose your neighbors; however, what can choose is how you put up with them. After growing tired of the folks next door failing to turn down their stereo, Maker “Jamil” came up with an ingenious way to put an end to the noisy behavior: fight the loud music with, well, even louder music.

As you can see in the video below, Jamil programmed an Arduino Uno with a microphone sensor to detect whenever the nearby resident’s tunes exceeded his preferred threshold. When this occurs, it triggers a CD player to play incredibly annoying music through his massive speakers. His track of choice? “Who Let the Dogs Out?” by The Baha Men.

"Why worry? Each of us is wearing an unlicensed nuclear accelerator on his back." That could be you with this DIY Ghostbusters Proton Pack!

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The post Check Out This Amazing Ghostbusters Proton Pack appeared first on Make: DIY Projects and Ideas for Makers.

Anyone who has ever watched Ghostbusters is surely familiar with the iconic proton pack–a handheld wand connected to a backpack-sized particle accelerator used for capturing ghosts. With a remake of the ‘80s flick about to hit theaters, what better time for a DIY prop equipped with full-featured user control and Hollywood-like effects?

That’s exactly what John Finocchiaro has done using a bunch of household items, including a five gallon bucket for the cyclotron, a garlic powder container for the N-Filter, a hairbrush for the PKE meter, spark plug wire, cardboard tubes, pill bottles, handles from power tool cases, a couple electrical boxes, and some other miscellaneous parts.

The proton pack is based on an Arduino Uno along with a Seeed Studio SD card shield containing .WAV files. The Arduino supplies all of the sound and light effects, except for the cyclotron lights which use a 555 timer and 4017 decade counter. The sound is amplified through an old computer speaker board, while two homemade boards control the lights.

The red lights on the cyclotron area are supposed to be asymmetrical. This project took two weekends to make, one for the pack and one for the gun. It is attached to a homemade  PVC “ALICE” frame. I tried to make it as light as possible, the whole unit weighs just 13 lbs. Its not fully “screen accurate” but more like a “Model 3″ version. The addition of a bunch of actual electronic components make it look more like it is a  functional unit instead of a prop.

The power meter on the gun and pack are synced to show an accumulating “charge” while a generator sound plays. When armed, the lights on the gun blink and the generator sound intensifies. When it’s fired, the barrel lights and the blast sound plays as the charge meter decreases to zero. It then shuts off and recharges.

Sometimes the journey is as interesting as the destination, and that’s certainly the case with [Marc]’s pursuit of measuring his sleep apnea (PDF, talk slides. Video embedded below.). Sleep apnea involves periods of time when you don’t breathe or breathe shallowly for as long as a few minutes and affects 5-10% of middle-aged men (half that for women.) [Marc]’s efforts are still a work-in-progress but along the way he’s tried a multitude of things, all involving different technology and bugs to work out. It’s surprising how many ways there are to monitor breathing.

His attempts started out using a MobSenDat Kit, which includes an Arduino compatible board, and an accelerometer to see just what his sleeping positions were. That was followed by measuring blood O2 saturation using a cheap SPO2 sensor that didn’t work out, and one with Bluetooth that did work but gave results as a graph and not raw data.

Next came measuring breathing by detecting airflow from his nose using a Wind Sensor, but the tubes for getting the “wind” from his nose to the sensor were problematic, though the approach was workable. In parallel with the Wind Sensor he also tried the Zeo bedside sleep manager which involves wearing a headband that uses electrical signals from your brain to tell you what sleep state you’re in. He particularly liked this one as it gave access to the data and even offered some code.

And his last approach we know of was to monitor breathing by putting some form of band around his chest/belly to measure expansion and contraction. He tried a few bands and an Eeonyx conductive textile/yarn turned out to be the best. He did run into noise issues with the Xbee, as well as voltage regulator problems, and a diode that had to be bypassed.

But while [Marc]’s list of approaches to monitor sleep is long, he hasn’t exhausted all approaches. For example there’s monitoring a baby using lasers to detect whether or not the child is still breathing.

[Via Adafruit]