A Lesson On Zener Regulators

October 11, 2017 by 40 Comments

For the longest time, Zener diode regulators have been one of those circuits that have been widely shared and highly misunderstood. First timers have tried to use it to power up their experiments and wondered why things did not go as planned. [James Lewis] has put up a worth tutorial on the subject titled, “Zener Diode makes for a Lousy Regulator”  that clarifies the misconceptions behind using the device.

[James Lewis] does an experiment with a regulator circuit with an ESP8266 after a short introduction to Zener diodes themselves. For the uninitiated, the Zener diode can operate in the reverse bias safely and can do so at a particular voltage. This allows for the voltage across the device to be a fixed value.

This, however, depends on the current flowing through the circuit which in turn relies on the load. The circuit will work as expected for loads the draw a small amount of current. This makes it suitable for generating reference voltages for microcontrollers and such.

To make a Zener into a “proper” voltage regulator, you just need to buffer the output with an amplifier of some kind. A single transistor is the bare minimum, but actually can work pretty well. You might also add a capacitor in parallel with the Zener to smooth out some of its noise.

Zener diodes are wonderful little devices and write-ups like these are indispensable for beginners and should be shared more often like the Zener and Schottky Tutorial and Diodes as a Switch.

 

Fix Everything And Get Your Own Flailing Arms Tube Man

October 11, 2017 by 20 Comments

The staple of used car dealerships that prompted Houston to ban all ‘attention getting devices’ is called an ‘air dancer’ and was invented in 1996. And now you can build your own, even if until now the space requirements kept you from doing so.

[dina Amin] shows how to make one from a bunch of discarded hair dryers and stuff everybody is likely to find in his or her workshop. While the build as such is rather basic — these things are really simple devices after all — [dina Amin]’s project video takes us through the interesting detours that turn a build into a project. It touches on the topics of painting plastics, hardware repairs, diagnosing and fixing DC motors, and how hair dryers actually work. As an added bonus we get a good-looking solution for fixing that enclosure with the worn out threads. All that in five minutes flat.

And while you might not know if you need one, [dina Amin]’s wacky waving inflatable arm flailing arm tube man is pretty much guaranteed to work. Unlike this one.

Continue reading “Fix Everything And Get Your Own Flailing Arms Tube Man” →

Terrible Cluster Of PIs

October 11, 2017 by 36 Comments

When we first saw [Ajlitt’s] Hackaday.io project Terrible Cluster we thought, perhaps, he meant terrible in the sense of the third definition:

3. exciting terror, awe, or great fear; dreadful; awful. (Dictionary.com)

After looking at the subtitle, though, we realized he just meant terrible. The subtitle, by the way, is: 5 Raspberry PI Zeros. One custom USB hub. Endless disappointment.

There are four Raspberry Pi Zero boards that actually compute and one Raspberry Pi Zero W serves as a head node and network router. The total cost is about $100 and half of that is in SD cards. There’s a custom USB backplane and even a 3D-printed case.

At first, using five tiny computers in a cluster might not seem like a big deal. Benchmarking shows the cluster (with a little coaxing) could reach 1.281 GFLOPS, with an average draw of 4.962W. That isn’t going to win any world records. However, the educational possibilities of building a $100 cluster that fits in the palm of your hand is interesting. Besides, it is simply a cute build.

We’ve seen much larger Pi clusters, of course. You might be better off with some desktop CPUs, but — honestly — not much better.

Paperback: ePaper desktop monitor playing Doom

Hackaday Prize Entry: PaperBack Desktop EPaper Monitor

October 11, 2017 by 23 Comments

When we announced the Hackaday Prize with its Best Product category, [PK] polled his wife and co-workers about the idea of making a desktop monitor using 6″ 800×600 ePaper, which he has since built and calls the PaperBack. One such requirement for a monitor is to be able to connect to it using one of the usual desktop methods: VGA, DVI or HDMI. Given his previous experience making his own VGA card for the 2015 prize, he went with that. HDMI is in the works.

But it ended up being more than a desktop monitor. He first made a power and breakout board that a VGA input board would eventually connect to. To test it, he included a socket for plugging in an ESP32. With only one bodge he had the Hackaday logo displayed on the ePaper. He also now had the option of using it as a wireless internet connected display.

Moving on to VGA support, [PK] made a VGA input board using the MST9883 chip, which does the A/D conversion of the VGA RGB graphics signal and also recovers a pixel sampling clock from the HSYNC. His new VGA ePaper monitor has to identify itself to the VGA source, telling it dimensions, resolution and so on. This is called the EDID and was handled by the addition of an Atmel ATmega328 to the board. To finish it off, an LCMXO1200C FPGA does the high-speed conversions with the help of a 4 MBit SRAM framebuffer.

His very first test involved simply displaying the Hackaday logo using the ESP32, but now with the VGA input board he has it displaying Doom. Since it’s using ePaper it has only a 1-second refresh rate but it’s hard to come up with a more awesome way to proved that it works. He can also unplug it at any time and walk away with the latest screenshot intact. See it for yourself in the video below.

Continue reading “Hackaday Prize Entry: PaperBack Desktop EPaper Monitor” →

Hackerspaces Are Hard: Safety

October 11, 2017 by 64 Comments

Safety is one of those topics that often elicits a less-than-serious response from some tool users. For these folks, they assume their elite skills will protect them and as long as they pay attention, they never will get hurt. This explains the prevalence of the nickname “Stubby” among this population. On the opposite end of the spectrum, safety is also one of those areas where people who don’t know a lot about tools can overreact. Imagine a whole table of kids wearing goggles as one of them gingerly melts some solder. You don’t want solder in your eye, but that’s just not going to happen under normal circumstances.

And then there are freak accidents, which are a reality. On September 20th, a leaking propane tank exploded at Sector67’s new workshop, severely injuring Chris Meyer. Far from a noob, Chris is one of the most experienced people in the shop and was a co-founder of the space. He has a long road of healing ahead of him, and as seems to be the sad necessity these days, he has a GoFundMe campaign to help both with his medical expenses and to help refurbish the workshop. The Foothills Community Workshop also burned to the ground recently, although fortunately no one was injured.

All in all, hackerspaces seem to be reasonably safe, particular considering the challenges they face — or more fairly, the risks associated with the typical hackerspace’s openness. Most hackerspaces allow anyone who pay dues to be a member. There is a wide range of backgrounds, competencies, and judgments represented with, how shall I put it, some unusual viewpoints that might hinder rule-following. And once the member has a fob or key, it’s open season on any kind of tool in the place right? Not everything can have a lock on it.

Here are a few simple rules that have emerged over the years, and may help your hackerspace navigate the twin dangers of complacency and paralyzed fear while preparing for the freak accidents that may simply come to pass.

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Friday Hack Chat: The Incredible BeagleBoard

October 11, 2017 by 12 Comments

Over the last year or so, the BeagleBoard community has seen some incredible pieces of hardware. The BeagleBone on a Chip — the Octavo OSD335x — is a complete computing system with DDR3, tons of GPIOs, Gigabit Ethernet, and those all-important PRUs stuffed into a single piece of epoxy studded with solder balls. This chip made it into tiny DIY PocketBones and now the official PocketBeagle is in stock in massive quantities at the usual electronic component distributors.

For this week’s Hack Chat, we’re talking about the BeagleBoard, BeagleBone, PocketBeagle, and PocketBone. [Jason Kridner], the co-founder of BeagleBoard and beagle wrangler, will be on hand to answer all your questions about the relevance of the Beagle platform today, the direction BeagleBoard is going, and the inner workings of what is probably the best way to blink LEDs in a Linux environment.

Topics for this Hack Chat will include the direction BeagleBoard is going, the communities involved with BeagleBoard, and how to get the most out of those precious programmable real-time units. As always, we’re taking questions from the community, submit them here.

As an extra special bonus, this week we’re giving away some hardware. Digi-Key has offered up a few PocketBeagle boards. If you have an idea for a project, put it on the discussion sheet and we’ll pick the coolest project and send someone a PocketBeagle.

join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat will be going down noon, Pacific time on Friday, October 13th. Wondering why the Brits were the first to settle on a single time zone when the US had a more extensive rail network and the longitude so time zones made sense? Here’s a time zone converter! Use that to ponder the mysteries of the universe.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Making Ice Cream With Heavy Metal

October 11, 2017 by 25 Comments

After his last project left him with an eleven-pound block of aluminum, [Jason] got to thinking of what most of us would in that situation: fresh made ice cream. His mind was on the frozen concoctions of the aptly named Cold Stone Creamery, a mall food court staple where a chilled stone is used to turn fresh ingredients into made to order sundaes.

[Jason] did the math and found that an eleven-pound chunk of aluminum can absorb a little over 67,000 joules, which is over twice the energy required to freeze 100 g of water. In place of water he would be using cream, condensed milk, and strawberries, but believed there was a large enough safety factor to account for the differences between his ingredients and pure water.

His first attempt didn’t go exactly as planned, but with his Flir One he was able to back up his theoretical numbers with some real-world data. He found that he needed to start the aluminum block at a lower temperature before adding his ingredients, and through experimentation determined the block only had enough energy to freeze 30 g of liquid.

In the end [Jason] was satisfied with the frozen treat he managed to make from the leftovers of his radial mill project, but theorizes that an ever better solution would be to use a brine solution and drop the aluminum block all together.

Of course, if putting food on a slab of metal from your workshop doesn’t sound too appealing, you could always go the NASA route and freeze dry it. Either method will probably make less of a mess than trying to print objects with it.