Planet Arduino

Hackaday.io user [peterquinn] has encountered a problem with his recently unruly cat peeing under the dining table. Recognizing that the household cat’s natural enemy is the spray bottle, he built an automatic cat sprayer to deter her antics.

The build is clear-cut: an Arduino Uno clone for a brain, an MG995 servo, PIR sensor, spray bottle, and assorted electronics components. [peterquinn] attached the servo to the spray bottle with a hose clamp — ensuring that the zero position is pointing at the trigger — and running a piece of cabling around the trigger that the servo will tug on. Adding a capacitor proved necessary after frying the first Uno clone, as the servo powering up would cause the Uno to reset.

The code is set up to trigger the servo — spraying the cat twice — once the PIR detects the cat for more than ten seconds. After toying with a few options, [peterquinn] is using a 9V, 2A power supply that works just fine. For now, he hopes the auto-sprayer should do the trick. If it somehow doesn’t work, [peterquinn] has mused that a drastic upgrade to the vacuum may be necessary.

Using a series of etched acrylic panes, the “Lixie” display can show numbers in the style of a Nixie tube.

Nixie tubes are beautiful pieces of display hardware that are no longer in production, and are becoming harder and harder to find. They also generally require relatively high DC voltages to operate, making them difficult and potentially dangerous. Connor Nishijima, however, has come up with an alternative called the Lixie.

This laser-cut item employs etched panes of acrylic to reflect the light from WS2812B LEDs as required, revealing digits 0-9. Since the LEDs are RGB, different colors can be selected as desired.

Edge-lighting panes of acrylic etched with a design has been done for decades, but they’ve always been static information like an “EXIT” sign. If you stack multiple panes of acrylic (each with a unique design) and light them individually, you can change what design the user sees! This makes edge-lighting perfect for a numeric display! And since I love the look of Nixies, we’ll emulate the typography as well. At the end of the day, what I’ve made is a beautiful over-sized numeric display using WS2812Bs and a laser cut digit assembly!

You can find more about this “modernized Nixie tube” on Hackaday.io.

With Timothy Giles’ rotating digital picture frame, you’ll never have to endure black bars around your vertical images again!

Rather than accept the poor presentation of vertical images that normal displays offer, Giles instead made his own out of a discarded 27-inch LCD TV. A Raspberry Pi displays the images sideways, then uses an Arduino with a stepper shield to rotate the TV to compensate.

Mechanically, he uses a herringbone gear set to turn the TV, while the Arduino accelerates and decelerates the TV’s rotation to give a smooth transition. It’s a very cool project, and one that makes you wonder “why didn’t I think of that?”

You can find more about Giles’ FlipFrame project at his Hackaday.io page, including code and mechanical design files if you want to build your own!

With Alain Mauer’s Arduino glasses and a Bluetooth multimeter, electrical data is always in view!

If you’re in a job where you have to take readings inside a live electrical panel, one thing that’s inconvenient, and even dangerous at times, is having to look away from your hands to read your multimeter. With hopes of “making an engineer’s life easier and safer,” Mauer solved this problem using an Arduino Pro Micro and a BLE module to show data from a Bluetooth-enabled multimeter. Now he can see data on a display that looks similar to a Google Glass device. Perhaps this method could be expanded to other devices in the future!

If you’d like to build your own glasses, a description and 3D printing files can be found on Hackaday.io.

Spectroscopy is an incredible tool for chemical analysis–and now you can make your own Bluetooth-enabled device with an Arduino Pro Mini.

If you took advanced chemistry classes, you may have had the opportunity to work with a spectrometer. It probably seemed like a magical gadget, identifying the chemicals in a substance through its light characteristics unlike the experimental methods you previously had to use.

Using off-the-shelf components–including an Arduino, a Bluetooth module, an LED, optical filters, and a LiPo battery–housed inside a 3D-printed case, the WiSci aims to take this tool out of the lab, and into the “real world.” By following the instructions on its project page, you can build one for just under $250.

What’s really neat is that the portable spectrometer can even scan a fruit and then wirelessly send the data over to an accompanying Android app to tell you whether or not the fruit is ripe. (You can view its IEEE Spectrum article for a little more background on that!)

A spectrometer is a very powerful tool. By analysing intensity/wavelength pairs of the interacted EM radiation with the material under study, detailed information like its chemical composition, crystal structure and other elemental information can be extracted. It can also be used for food analysis. For example, it can reveal adulteration in milk or oil and analyse toxins to understand causes of food poisoning to name a few uses.

To create your own, check out its Hackaday.io page here.

Back in the late 1970s, comedian Steve Martin had a bit about “Let’s get small!” Over on Hackaday.io, [Daniel Grießhaber], has taken that call to heart. He’s been working on DIL-Duino, a minuscule form factor Arduino in an 8-pin DIP format.

Built with an ATtiny85, the board has an area of just under 75 square millimeters (less than 8 mm x 10 mm). If you add the USB port, it still comes in at just over 144 square millimeters. [Daniel] found other small Arduino boards like the Olimexino-85s and the Nanite are not as small as his design.

The module has a QFN CPU and castellated holes around the perimeter for mounting. With pin headers, this would easily fit into a breadboard (as [Daniel] shows) or you could mount it directly to another board like a surface mount device. In fact, that’s the reason for using castellated holes: you can inspect that the solder joint at the mating SMD pad is good. You sometimes hear the technique called half-vias or leadless chip carrier.

If you note, [Daniel] used an oversized board with full holes around the perimeter and then had the board maker score the board, so the holes are cut in half. This is a better technique than trying to drill half holes on the board edge, which is difficult to do.

Naturally, this isn’t the first tiny Arduino we’ve seen. If you are an ARM fan, there’s some little bitty cards for it, too, although not quite as small as DIL-Duino.

You could sometimes be forgiven for thinking that making popular music has become too easy. With a laptop and suitable software almost anybody can now assemble something that had they secured the services of a canny promoter would be in with a shot at stardom. So many performances have been reduced to tightly choreographed dance acts to mask the absence of musicians or indeed musical talent, and our culture is poorer for it. It’s not that music made with modern technology or outside the performance is an indicator of lack of talent, indeed when a truly talented musician makes something with the resources of a modern technology the results are astounding. Instead it perhaps seems as though the technology is cheapened by an association with mediocrity when it should be a tool of greatness.

So it was with pleasure that we noticed a fresh project on Hackaday.io this morning which provides a marriage of accessible music technology and a requirement for performance. [Ernest Warzocha] has made a wooden sequencer.

It’s true, audio sequencers are old hat, so a new one will have to work hard to enthuse a seasoned Hackaday reader who’s seen it all. What makes [Ernest’s] sequencer different is that he’s made one with a very physical interface of wooden pucks placed in circular recesses on a wooden surface. Each recess has an infra-red reflective sensor that detects the surface texture of the puck placed in it and varies the sample it plays accordingly. It’s all held together underneath by an Arduino, and MP3 samples are played by a Sparkfun MP3 shield. At a stroke, he has turned the humble sequencer from a workaday studio tool into a performance art form that you can see in the video below, and we like that.

Home made sequencers have a special place in maker culture, and as you might expect over the years we’ve featured quite a few of them. Shift registers, CMOS analogue switches or even turntables as the sequencer elements, Lego as a human interface, a sequencer made from a cash register, and a rather lovely steampunk sequencer, to name but a few. So this one joins a rich tradition, and we look forward to more in the future.

Range finders are amazing tools for doing pretty much anything involving distance calculations. Want to blink some lights when people are nearby? There’s a rangefinder for that. Need to tell how far away the next peak of a mountain range is? There’s a rangefinder for that. But if you’re new to range finders and want one that’s hackable and configurable, look no further than the SF02/F rangefinder with the Arduino shield, and [Laser Developer]’s dive into what this pair can do.

Once the rangefinder and shield have been paired is when the magic really starts to happen. Using USB, the Arduino can instantly report a huge amount of raw data coming from the rangefinder. From there, [Laser Developer] shows us how to put the device into a “settings” mode which expands the capabilities of the rangefinder even more. The data can be dumped into a graph, for example, which can show trends between distance, laser strength, and many other data sets. [Laser Developer] goes one step further and demonstrates how to use this to calculate the speed of light, but from there pretty much anything else is possible as well.

And while you can just buy a rangefinder off the shelf, they are fairly limiting in their features and can cost exponentially more. This is a great start into using a tool like this, especially if you need specific data or have a unique application. But, if laser range finding isn’t for you or if this project is too expensive, maybe this $5 ultrasonic rangefinder will work better for your application.

Putting an full microcontroller platform in a DIP format is nothing new – the Teensy does it, the Arduino nano does it, and a dozen other boards do it. [Alex] and [Alexey] aren’t content with just a simple microcontroller breakout board so they’re adding a radio, an OLED, an SD card reader, and even more RAM to the basic Arduino platform, all in a small, easy to use package.

The DIPDuino, as [Alex] and [Alexy] are calling it features an ATmega1284 processor. To this, they’re adding a 128×32 pixel OLED, a micro SD slot, and 1Mbit of SRAM. The microcontroller is a variant that includes a 2.4 GHz Zigbee radio that allows for wireless connections to other DIPDuinos.

What are [Alex] and [Alexey] going to do with their cool little board? They’re planning on using the OLED for a watch, improve their software so the firmware can be updated from the SD card, and one of [Alex]’s friends wants to build a RepRap controller with one of these. There’s a lot of potential with this board, and we’re interested in seeing where the guys take the project from here.

[David Nghiem] has been working with circuitry designed to read signals from muscles for many years. After some bad luck with a start-up company, he didn’t give up and kept researching his idea. He has decided to share his innovations with the hacker community in the form of a wearable suit that reads muscle signals.

It turns out that when you flex a muscle, it gives off a signal called a Surface ElectroMyographic signal, or SEMG for short. [David] is using an Arduino, digital potentiometer and a bunch of op amps to read the SEMG signals. LEDs are used to display the signal levels.

The history behind [David’s] project dates back to the late twentieth century, which he eloquently points out – “Holy crap that was a long time ago”. He worked with the MIT Aero Astro Lab and the Boston University Neuromuscular Research Center where he worked on a robotic arm for astronauts. The idea being to apply an opposing force to the arm to help prevent muscle deterioration.

Be sure to check out [David’s] extensive and well documented work, along with the several videos showing his projects at various stages of completion. If this gives you the electromyography bug, check out this guide on detecting the signals and an application of the concept for robotic prosthesis.