Year: 2017

Ultrasonic Raspberry Pi Piano

April 22, 2017 by 9 Comments

Cheap stuff gets our creative juices flowing. Case in point? [Andy Grove] built an eight-sensor HC-SR04 breakout board, because the ultrasonic distance sensors in question are so affordable that a hacker can hardly avoid ordering them by the dozen. He originally built it for robotics, but then it’s just a few lines of code to turn it into a gesture-controllable musical instrument. Check out the video, embedded below, for an overview of the features.

His Octasonic breakout board is just an AVR in disguise — it reads from eight ultrasonic sensors and delivers a single SPI result to whatever other controller is serving as the brains. In the “piano” demo, that’s a Raspberry Pi, so he needed the usual 5 V to 3.3 V level shifting in between.

The rest is code on the Pi that enables gestures to play notes, change musical instruments, and even shut the Pi down. The Pi code is written in Rust, and up on GitHub. An Instructable has more detail on the hookups.

All in all, building a “piano” out of robot parts is surely a case of having a hammer and every problem looking like a nail, but we find some of the resulting nail-sculptures arise that way. This isn’t the first time we’ve seen an eight-sensor ultrasonic setup before, either. Is 2017 going to be the year of ultrasonic sensor projects? Continue reading “Ultrasonic Raspberry Pi Piano” →

How Many Watts Are You Using?

April 22, 2017 by 28 Comments

One of the best smart home hacks is implementing an energy monitor of some kind. It’s easy enough to say that you’re trying to save energy, but without the cold hard data, it’s just talk. Plus, it’s easy and a great way to build up something DIY that the whole family can use.

[Bogdan] built up a simple whole-apartment power monitor from scratch over the weekend, and he’s been nice enough to walk us through the whole procedure, starting with picking up a split-core CT sensor and ending up with a finished project.

The brains of his project are an ESP8266 module, which means that he needed to adapt the CT sensor to put out a voltage that lies within the chip’s ADC range of 0 V to 3.3 V. If you’re undertaking an energy monitor project, it’s as easy as picking the right burden resistor value and then shifting the ground-centered voltage up by 1.6 V or so. We say it’s easy, but it’s nice to have a worked example and some scope shots. The microcontroller reads the ADC frequently, does a little math, and you’re done. Continue reading “How Many Watts Are You Using?” →

Hackaday Prize Entry: A Complete Suite Of Biomedical Sensors

April 22, 2017 by 13 Comments

The human body has a lot to tell us if we only have the instruments to listen. Unfortunately, most of the diagnostic gear used by practitioners is pricey stuff that’s out of range if you just want to take a casual look under the hood. For that task, this full-featured biomedical sensor suite might come in handy.

More of an enabling platform than a complete project, [Orlando Hoilett]’s shield design incorporates a lot of the sensors we’ve seen before. The two main modalities are photoplethysmography, which uses the MAX30101 to sense changes in blood volume and oxygen saturation by differential absorption and reflection of light, and biopotential measurements using an instrumentation amplifier built around an AD8227 to provide all the “electro-whatever-grams” you could need: electrocardiogram, electromyogram, and even an electrooculogram to record eye movements. [Orlando] has even thrown on temperature and light sensors for environmental monitoring.

[Orlando] is quick to point out that this is an educational project and not a medical instrument, and that it should only ever be used completely untethered from mains — battery power and Bluetooth only, please. Want to know why? Check out the shocking truth about transformerless power supplies.

The HackadayPrize2017 is Sponsored by:

Thanks to [fustini] for the tip.

Lens Mount

X-Ray Imaging Camera Lens Persuaded To Join Micro Four Thirds Camera

April 22, 2017 by 16 Comments

Anyone who is into photography knows that the lenses are the most expensive part in the bag. The larger the aperture or f-stop of the lens, the more light is coming in which is better for dimly lit scenes. Consequently, the price of the larger glass can burn a hole in one’s pocket. [Anthony Kouttron] decided that he could use a Rodenstock TV-Heligon lens he found online and adapt it for his micro four-third’s camera.

The lens came attached to a Fischer Imaging TV camera which was supposedly part of the Fluorotron line of systems used for X-ray imaging. We find [Anthony’s] exploration of the equipment, and discovery of previous hacks by unknown owners, to be entertaining. Even before he begins machining the parts for his own purposes, this is an epic teardown he’s published.

Since the lens was originally mounted on a brass part, [Anthony Kouttron] knew that it would be rather easy to machine the custom part to fit standardized lens adapters. He describes in detail the process for cleaning out the original mount by sanding, machining and threading it. Along the way you’ll enjoy his tips on dealing with a part that, instead of being a perfect circle on the outside, had a formidable mounting tab (which he no longer needed) protruding from one side.

The video after the break shows the result of shooting with a very shallow depth of field. For those who already have a manual lens but lack the autofocus motor, a conversion hack works like a charm as well.

Continue reading “X-Ray Imaging Camera Lens Persuaded To Join Micro Four Thirds Camera” →

Little Laser Light Show Is Cleverly Packaged, Cheap To Build

April 22, 2017 by 9 Comments

We’re suckers for any project that’s nicely packaged, but an added bonus is when most of the components can be sourced cheaply and locally. Such is the case for this little laser light show, housed in electrical boxes from the local home center and built with stuff you probably have in your junk bin.

When we first came across [replayreb]’s write-up and saw that he used hard drives in its construction, we assumed he used head galvanometers to drive the mirrors. As it turns out, he used that approach in an earlier project, but this time around, the hard drive only donated its platters for use as low mass, first surface mirrors. And rather than driving the mirrors with galvos, he chose plain old brushed DC motors. These have the significant advantage of being cheap and a perfect fit for 3/4″ EMT set-screw connectors, designed to connect thin-wall conduit, also known as electromechanical tubing, to electrical boxes and panels. The motors are mounted to the back and side of the box so their axes are 90° from each other, and the mirrors are constrained by small cable ties and set at 45°. The motors are driven directly by the left and right channels of a small audio amp, wiggling enough to create a decent light show from the laser module.

We especially like the fact that these boxes are cheap enough that you can build three with different color lasers. In that case, an obvious next step would be bandpass filters to split the signal into bass, midrange, and treble for that retro-modern light organ effect. Or maybe figuring out what audio signals you’d need to make this box into a laser sky display would be a good idea too.

Continue reading “Little Laser Light Show Is Cleverly Packaged, Cheap To Build” →

The Internet Of Rice Cookers

April 22, 2017 by 28 Comments

You’d be forgiven for thinking this was going to be an anti-IoT rant: who the heck needs an IoT rice cooker anyway? [Microentropie], that’s who. His rice cooker, like many of the cheapo models, terminates heating by detecting a temperature around 104° C, when all the water has boiled off. But that means the bottom of the rice is already dried out and starting to get crispy. (We love the crust! But this hack is not for us. This hack is for [Microentropie].)

So [Microentropie] added some relays, a temperature sensor, and an ESP8266 to his rice cooker, creating the Rice Cooker 2.0, or something. He tried a few complicated schemes but was unwilling to modify any of the essential safety features of the cooker. In the end [Microentropie] went with a simple time-controlled cooking cycle, combined with a keep-warm mode and of course, notification of all of this through WiFi.

There’s a lot of code making this simple device work. For instance, [Microentropie] often forgets to press the safety reset button, so the ESP polls for it, and the web interface has a big red field to notify him of this. [Microentropie] added a password-protected login to the rice cooker as well. Still, it probably shouldn’t be put on the big wide Internet. The cooker also randomizes URLs for firmware updates, presumably to prevent guests in his house from flashing new firmware to his rice cooker. There are even custom time and date classes, because you know you don’t want your rice cooker using inferior code infrastructure.

In short, this is an exercise in scratching a ton of personal itches, and we applaud that. Next up is replacing the relays with SSRs so that the power can be controlled with more finesse, adding a water pump for further automation, and onboard data logging. Overkill, you say? What part of “WiFi-enabled rice cooker” did you not understand?

[Hari] Prints An Awesome Spider Robot

April 22, 2017 by 14 Comments

Although we have strong suspicions that the model’s designer failed entomology, this spider robot is very cool. [Hari Wiguna] made one, and is justifiably thrilled with the results. (Watch his summary on YouTube embedded below.)

Thanks to [Regis Hsu]’s nice design, all [Hari] had to do was order a hexapod’s dozen 9g servos for around $20, print out the parts, attach an Arduino clone, and he was done. We really like the cutouts in the printed parts that nicely fit the servo horns. [Hari] says the calibration procedure is a snap; you run a sketch that sets all the servos to a known position and then tighten the legs in place. Very slick.

The parts should print without support on basically any printer. [Hari]’s is kinda janky and exhibits all sorts of layer-to-layer irregularities (sorry, man!) but the robot works perfectly. Which is not to say that [Hari] doesn’t have assembly skills — check out the world’s smallest (?) RGB LED cube if you think this guy can’t solder. Of course, you can entirely sidestep the 3D-printed parts and just fix a bunch of servos together and call it a robot. It’s harder to make building a four-legger any easier than these two projects. What are you waiting for?

Continue reading “[Hari] Prints An Awesome Spider Robot” →