How Does A Buck Converter Work Anyway?

June 4, 2016 by Gerrit Coetzee 30 Comments

[Great Scott] should win an award for quickest explanation of a buck converter. Clocking in at five and a half minutes, the video clearly shows the operating principles behind the device.

It starts off with the question, what should you do if you want to drop a voltage? Many of us know that we can dim and brighten an LED using the PWM on an Arduino, but a closer inspection with an oscilloscope still shows 5V peaks that would be dangerous to a 3.3V circuit. He then adds an inductor and diode, this keeps the current from dropping too fast, but the PWM just isn’t switching fast enough to keep the coil energized.

A small modification to the Arduino’s code, and the PWM frequency is now in the kHz range. The voltage looks pretty good on the oscilloscope, but a filter cap gets it to look nice and smooth. Lastly, he shows how when the load changes the voltage out looks different. To fix this a voltage divider feeds back the information to the Arduino, letting it change the PWM duty to match the load.

In the last minute of the video he shows how to hook up off-the-shelf switching regulators, whose support components are now completely demystified as the basic principles are understood. Video after the break.

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Hacklet 110 – Optical Microscopy Projects

June 4, 2016 by Adam Fabio No comments

Humans have always wanted to make small things bigger. To see that which is unseen with the naked eye. The inventor of the original microscope happened sometime in the 1600’s, though the inventor is still contested. Some say it was Cornelis Drebbel, while others say Hans Lippershey. Galileo Galilei’s compound microscope is probably the most well-known ancient magnifier. Regardless of who created the device, hackers, makers, engineers, and scientists have used microscopes to study mysteries of biology, geology, electronics, and just about anything else you can imagine.

This is a fitting topic for this week’s Hacklet at is aligns well with the Citizen Scientist challenge round of the Hackaday Prize which began on Monday. Making quality microscopes more widely available is one of many great starting ideas for an entry. Let’s take a look at some of the best microscopy projects on Hackaday.io!

We start with [J. Kha] and Armed Microscope. [J. Kha] was one of the backers of the original uArm over at Kickstarter. He also does quite a bit of work with electronics. After fighting with a cheap USB microscope, he realized he had the perfect platform to control it. Microscopes usually are stationary, with the object being viewed moved on a stage. [J. Kha] turned things upside down by mounting the microscope on his uArm. An Arduino Yun controls the system. The Yun also allows him to stream the microscope’s video over the internet using the mjpg-streamer library. [J. Kha] did have some power issues at first, but he’s got his regulators all sorted out now.

Next we have [andyhull] with Adding a light touch to a “classic” microscope. A lucky dumpster find netted [Andy] a pile of old broken microscopes. From this he was able to build a working classic stereo scope. This was a Gillet & Sibert stereo compound scope. Like most microscopes of its time, the old GS used standard incandescent or halogen lights for illumination. The old bulbs were long gone, and would have been a pain to replace. [Andy] switched his scope over to LED illumination. He ended up using a commercially available LED “bulb” designed to replace type 1157 automotive tail light bulbs. This type of LED is designed to run on 12 volt power which simplifies the wiring. The small LED flashlight in a custom mount also provides a bit of help for opaque subjects.

Next up is [Andre Maia Chagas] with Flypi – cheap microscope/experimental setup. Flypi is [Andre’s] entry in the 2106 Hackaday Prize. Flypi is more than just a microscope, it’s a 3D printed data collection and image analysis device for hackers and scientists alike. A Raspberry Pi 2 or 3 controls the show. Images come in through Pi Camera with an M12 lens. The Pi runs some open source Python code allowing it to acquire and analyze images. It also has an Arduino as a co-processor to handle anything a particular experiment may need – like RGB LEDs, heaters, manipulators, you name it. Andre sees Flypi as having uses in everything from fluorescence imaging to optogenetics and thermogenetics.

Finally we have [Jarred Heinrich] with Stagmo: Microscope Stage Automator. Positioning samples under high magnification requires a steady hand. Trying to image them makes things even harder. To help with this, microscopes have stages. Fine lead screws manually controlled by knobs allow the user to precisely position any subject. Automated stages are available as well, but they can get quite expensive. [Jarred] recognized that the microscope stage is an X-Y platform like any CNC, laser, or 3D printer. He used an Arduino and a motor shield to control a couple of stepper motors. The motors are coupled to the stage knobs with rubber belts. While the mounting system looks a little wobbly, but it got the job done, and didn’t require any modifications to the microscope itself.

Optical microscopes are just one type of scope you’ll find on Hackaday.io. There are also atomic force microscopes, scanning electron microscopes, and more! I’ll cover those on a future Hacklet. If you want to see more awesome optical microscopy projects, check out our new optical microscope projects list! If I missed your project, don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Fixing A Broken Bandsaw With A Custom Steel Part

June 4, 2016 by Donald Papp 16 Comments

When a large bandsaw broke down due to a cast iron part snapping in two, [Amr] took the opportunity to record the entire process of designing and creating a solid steel replacement for the broken part using a (non-CNC) mill and lathe.

For those of us unfamiliar with the process a machinist would go through to accomplish such a thing, the video is extremely educational; it can be sobering both to see how much design work happens before anything gets powered up, and just how much time and work goes into cutting and shaping some steel into what at first glance looks like a relatively uncomplicated part.

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Netbook Finds New Home In A Jaguar Dashboard

June 4, 2016 by Dan Maloney 19 Comments

You’d figure a luxury car like a Jaguar would have a high-end infotainment system. [RichTatham]’s Jag did, but the trouble was that it was a high-end system when a cassette deck and trunk-mounted CD changer were big deals. So naturally, he saw this as a great reason to modernize the system by grafting a netbook into the Jag’s dash. The results are fantastic!

Even though the Jag’s original system didn’t have much left that made it into the final project — the navigation system, CD changer, phone and even the amps ended up on the scrap heap — at least the dashboard instrument cluster proved to be very amenable to his mods. By substituting a climate control cluster from another model into his car, he was able to free up tons of space for the netbook’s 8″ display. A custom bezel and some clever brackets completed the head-end of the new system, and the look is as close to a factory install as you’re likely to find in an aftermarket mod. With the netbook stashed in the bay vacated by the OEM system, a GPS dongle, and a USB sound card connected to a 5.1 amp using the original speakers this jag is ready to bump. We bet that the system sounds as good as it looks, and with the added functionality of a Windows PC to boot.

For obvious reasons, lots of computers make it into hackers’ dashboards, whether they be Windows like this one, Samsung tablets or Nexus tablets running Android, and even phones. But [Rich]’s build is top notch, and takes in-car integrations to the next level.

[via r/diy]

Real-Time FPGA Finger Detection

June 4, 2016 by Elliot Williams 12 Comments

The student projects that come out of [Bruce Land]’s microcontroller- and FPGA-programming classes feature here a lot, simple because some of them are amazing, but also because each project is a building-block for another. And we hope they will be for you.

This time around, [Junyin Chen] and [Ziqi Yang] created a five-in-a-row video game that is controlled by a pointing finger. A camera, pointed at the screen, films the player’s hand and passes the VGA data to an FPGA. And that’s where things get interesting.

An algorithm in the FPGA detects skin color and, after a few opening and closing operations, comes up with a pretty good outline of the hand. The fingertip localization is pretty clever. They sum up the number of detected pixels in the X- and Y-axis, and since a point finger is long and thin, locate the tip because it’s going to have a maximum value in one axis and a minimum along the other. Sweet (although the player has to wear long sleeves to make it work perfectly).

How does the camera not pick up the game going on in the background? They use a black-and-white game field that the skin-color detection simply ignores. And the game itself runs in a Nios embedded processor in the FPGA. There’s a lot more detail on the project page, and of course there’s a demo video below.

We love to follow along with Prof. Land‘s classes. His video series is invaluable, and the course projects have been an inspiration.

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Control The Real World With An Arduino-Enabled Minecraft Mod

June 4, 2016 by Dan Maloney 8 Comments

Minecraft modding has become almost as popular as the block-based game itself, with tons of editors and tools available to create new kinds of blocks, mobs, and weapons. And now, with this mod framework that can talk to an Arduino, modders can build blocks that break out of the Minecraft world to control the real world.

While turning on a light from Minecraft is not exactly new, the way that MCreator for Arduino goes about it is pretty neat. MCreator is a no-code framework for building Minecraft mods, which allows modders to build new game capabilities with a drag and drop interface. The MCreator Arduino toolkit allows modders to build custom Minecraft blocks that can respond to in-game events and communicate with an Arduino over USB. Whatever an Arduino can do – light an LED, sense a button press – can be brought into the game. It’s all open-source and free for non-commercial use, which is perfect for the upcoming STEM-based summer camp season. We can think of some great projects that would really jazz up young hackers when presented through a Minecraft interface.

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Hackaday Prize Entry: Germanium Vision

June 3, 2016 by Brian Benchoff 29 Comments

The first digital cameras didn’t come out of a Kodak laboratory or from deep inside the R&D department of the CIA or National Reconnaissance Office. The digital camera first appeared in the pages of Popular Electronics in 1975, using a decapsulated DRAM module to create fuzzy grayscale images on an oscilloscope. For his Hackaday Prize project, [Alexander] is recreating this digital camera not with an easy to use decapsulated DRAM, but with individual germanium transistors.

Phototransistors are only normal transistors with a window to the semiconductor, and after finding an obscene number of old, Soviet metal can transistors, [Alex] had either a phototransistor or a terrible solar cell in a miniaturized package.

The ultimate goal of this project is to create a low resolution camera out of a matrix of these germanium transistors. [Alex] can already detect light with these transistors by watching a multimeter, and the final goal – generating an analog NTSC or PAL video signal – will “just” require a single circuit duplicated hundreds of times.

Digital cameras, even the earliest ones built out of DRAM chips, have relatively small sensors. A discrete image sensor, like the one [Alex] is building for his Hackaday Prize entry, demands a few very interesting engineering challenges. Obviously there must be some sort of lens for this image sensor, so if anyone has a large Fresnel sitting around, you might want to drop [Alex] a line.

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