Oh, Holey Light

September 30, 2020 by Brian McEvoy 18 Comments

We consider ourselves well-versed when it comes to the technical literature plastered on hardware store parts. Acronyms don’t frighten us, and our Google-fu is strong enough to overcome most mysteries. One bit of dark magic we didn’t understand was the gobbledygook on LED lamps. Wattage is easy and color temperature made sense because it corresponds with warm and cool colors, but Color Rendering Index (CRI) sounds like deep magic. Of course, some folks understand these terms so thoroughly that they can teach the rest of us, like [Jon] and [Kevin], who are building a light controller that corrects inadequacies in cheap lamps by installing several lamps into one unit.

We learned a lot by reading their logs, which are like the Cliff Notes from a lighting engineer’s textbook, but we’ll leave it as an exercise for the students to read through. Their project uses precise light sensors to measure the “flavor” of light coming off cheap lamps so you can mix up a pleasing ratio. In some ways, they are copying the effects of incandescent bulbs, which emit light relatively evenly across the visible light spectrum, right into the infrared. Unfortunately, cheap LEDs have holes in their spectrum coverage, and a Warm White unit has different gaps compared with Daylight, but combining them just right gives a rich output, without breaking the bank.

Check Your Pockets For Components

September 28, 2020 by Brian McEvoy 13 Comments

The ideal component tester is like a tricorder for electronics — it can measure whatever it is that you need it to, all the time. Maybe you have a few devices like an ohmmeter and maybe a transistor socket on our multimeter. But what do you do when you need to see if that thyristor is faulty? [Akshay Baweja] wants an everything-tester at the ready, so he’s building a comprehensive device that fits in a pocket. It will identify the type and size of: Continue reading “Check Your Pockets For Components” →

Digital Expression Via Harmonica

September 15, 2020 by Brian McEvoy 11 Comments

There is a good chance you clicked on this article with a mouse, trackball, trackpad, or tapped with your finger. Our hands are how most of us interact with the digital world, but that isn’t an option for everyone, and [Shu Takahashi] wants to give them a new outlet to express themselves. Some folks who cannot use their hands will be able to use the Magpie MIDI, which acts as a keyboard, mouse, MIDI device, and eventually, a game controller. This universal Human Interface Device (HID) differs from a mouth-operated joystick because it has air pressure sensors instead of buttons. The sensors can recognize the difference between exhalation and inhalation, so the thirteen ports can be neutral, positive, or negative, which is like having twenty-six discrete buttons.

The harmonica mounts on an analog X-Y joystick to move a mouse pointer or manipulate MIDI sound like a whammy bar. [Shu] knows that a standard harmonica has ten ports, but he picked thirteen because all twenty-six letters are accessible by a puff or sip in keyboard mode. The inputs outnumber the Arduino Leonardo’s analog inputs, so there is a multiplexor to read all of them. There was not enough time to get an Arduino with enough native ports, like a Teensy, with HID support baked in. Most of the structure is 3D printed, so parts will be replaceable and maybe even customizable.

Even with two working hands, we like to exercise different hardware, but the harmonica is a nifty tool to have attached to your computer.

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Finalists Announced For The 2020 Hackaday Prize

September 14, 2020 by Tom Nardi 8 Comments

In light of everything going on in 2020, the 7th annual Hackaday Prize is devoted to nurturing ideas that could literally help change the world. In a first, we partnered with several nonprofits to help identify some of today’s most difficult problems, ranging from conservation and disaster relief to the need for advanced assistive technology. With over $200,000 up for grabs, including microgrants to help teams work full-time on their projects, this year’s competition was designed to help bring critical solutions to fruition which otherwise might never see the light of day.

But it hasn’t been easy. The global pandemic has made it far more difficult to collaborate on projects in the way we’re all used to, parts have become harder to source, and many makers found themselves so engaged with grassroots efforts to combat COVID-19 that they found little time for anything else. But despite all of this uncertainty, we received hundreds of incredible entries from all over the globe.

It’s never easy to select who will move on to the next round of the competition. But with the help of our nonprofit partners, the panel of expert judges was able to whittle the list of entries down to the 34 finalists that produced some of the most impressive and impactful ideas the Hackaday Prize has ever seen. Let’s take a look at just a few of the projects that will be vying for the top prizes in November.

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Wooden Tank’s Movement Hinges On Hinges

September 9, 2020 by Brian McEvoy 28 Comments

When we first looked at this tank, we thought it was pretty cool. The sides are unpainted 1/2″ (12mm) plywood, so it is not flashy. The dimensions came from Google-fu-ing the heck out of the WWII Hetzer and scaling them to 1:6. What knocks our socks off is how much [Bret Tallent] made use of parts you would find in a hardware store or bicycle shop. He uses twin motors from electric bikes, and the wheels look like replacement shopping cart wheels. The best part is the treads, which are dozens of hinges fastened with pairs of bolts and nylon-insert nuts. Something is reassuring about knowing that a repair to your baby is no further than a bike ride.

We don’t know what started [Bret] on his path to sidewalk superiority, but we suspect he is cooped up like the rest of us and looking to express himself. Mini-Hetzer is not licensed by Power Wheels and never will be, so it probably won’t turn into a business anytime soon. There is a complete gallery starting with an empty plywood base, and the pictures tell the story of how this yard Jäger got to this point. There are plans to add a paintball gun and streaming video, so we’d advise that you don’t mess with the jack-o-lanterns on his block this year. Give his gallery a view and see if you don’t become inspired to cobble something clever from the hardware store too. Then, tell us about it.

Another creative hacker used wood for their tank body and the treads as well. If you like your treaded vehicles functional, we have one meant to taxi small planes over the tarmac.

Identifying Creatures That Go Chirp In The Night

September 8, 2020 by Tom Nardi 26 Comments

It’s common knowledge that bats navigate and search for their prey using echolocation, but did you know that the ultrasonic chips made by different species of bats are distinct enough that they can be used for identification? [Tegwyn☠Twmffat] did, which is why he came up with this impressive device capable of cataloging the different bats flying around at night.

Now this might seem like an odd gadget to have, but if you’re in the business of wildlife conservation, it’s not hard to imagine how this sort of capability might be useful. This device could be used to easily estimate the size and diversity of bat populations in a particular area. [Tegwyn☠Twmffat] also mentions that, at least in theory, the core concept should work with other types of noisy critters like rodents or dolphins.

Powered by the NVIDIA Jetson Nano, the unit listens with a high-end ultrasonic microphone for the telltale chirps of bats. These are then processed by the software and compared to a database of samples that [Tegwyn☠Twmffat] personally collected in local nature reserves. In the video after the break, you can also see how he uses a set of house keys jingling as a control to make sure the system is running properly.

As winner of the Train All the Things contest back in April, we’re eager to see how the Intelligent Wildlife Species Detector will fare as the competition heats up in the 2020 Hackaday Prize.

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Pocket-sized Device Sniffs Out Damp Masks

September 6, 2020 by Tom Nardi 13 Comments

The realities of wearing a mask when you go out, from forgetting the thing in the car to dealing with fogged up glasses, have certainly taken some getting used to for most of us. But not every issue is immediately obvious. For example, experts say that as a mask gets damp from exhalation or perspiration it becomes less effective. Which is precisely why [Rick Pannen] has designed the Mask Moisture Meter.

As deep as we are into the Microcontroller Era, we really appreciate the simplicity of this design. It’s just a 555 timer, a buzzer, some LEDs, and a handful of passive components to get them all talking to each other. There’s no firmware or programming required; just put a fresh battery in the holder and away you go. The traces of the PCB serve as a moisture detector, so when the board is pushed against something wet enough, the red LED and buzzer will go off to warn the user.

Now admittedly, there’s a point where you certainly won’t need an electronic gizmo to tell you a mask is wet. But as [Rick] demonstrates in the video after the break, the circuit is sensitive enough to indicate when there’s moisture in the material that might not be immediately obvious to the eye.

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