Monitor Power Consumption Of Low-Power Devices

February 28, 2018 by 14 Comments

Perhaps the most important consideration to make when designing a battery-operated device of any kind is the power consumption. Keeping it running for longer between battery changes is often a key design point. To that end, if you need to know how small programming changes will impact the power consumption of your device then [Daniel] has a great tool that you might find helpful: an ESP8266-based live power meter.

The power meter itself is battery-powered via a 600 mAh battery and monitors an e-paper module, which also displays information about power consumption. It runs using a NodeMCU and measures voltage and current across a 100-ohm resistor to calculate the power use, although the resolution does start to get noisy when the device is in standby/sleep mode. One presumes this could be solved by changing the value of the resistor in order to get more accurate measurements at the expense of losing accuracy during moments of high power consumption.

While this power monitor was built specifically to monitor power consumption on this particular e-paper display project, it should be easily portable into other battery-based systems that need fine tuning in order to maximize battery life. As a bonus, the display is already included in the project. There are ways of getting even more information about your battery usage, although if power consumption is important than you may want to stick with a more straightforward tool like this one.

FPGA Calculator Uses Joystick

February 28, 2018 by 10 Comments

FPGAs are great fun, but sometimes you need a few starter projects under your belt. These projects might be something you could just as well do with a CPU, but you have to start somewhere. [LambdaPI] recently shared a 4-bit calculator created using an FPGA, and you can see it in the video below.

The calculator uses a Papilio FPGA board and a LogicStart accessory board for the display and switches. The Papilio normally uses schematic-based entry and Arduino code, but [LambdaPI] used VHDL. You enter the two 4-bit numbers on the 8 switches and then the joystick selects one of four operations (add, subtract, multiply, and divide).

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Repairs You Can Print Contest: Meet The Winners

February 28, 2018 by 21 Comments

Six weeks ago, we asked you to show us your best 3D printed repairs for a chance to win $100 in Tindie credit and other prizes. You answered the call with fixes for everything from the stuff everyone has, like zippers and remotes, to the more obscure stuff, like amazing microscopes scavenged from dumpsters.

It was hard to whittle down the entries we received into the top 20 because you came up with so many awesome fixes. A few of them had us thinking hard about the definition of repair, but are brilliant in their own way.

So without further ado, we are pleased to announce the winners of our Repairs You Can Print contest. We also want to give honorable mention to those projects that wowed us with ingenuity.

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Katherine Johnson: Computer To The Stars

February 28, 2018 by 22 Comments

In 1962, John Glenn sat in his capsule waiting for his rocket engines to light-up and lift him to space. But first, he insisted that Katherine Johnson double-check the electronic computer’s trajectory calculations. While that’s the dramatic version of events given in the recent movie, Hidden Figures, the reality isn’t very far off. Glenn wasn’t sitting on the launchpad at the time, but during the weeks prior to launch, he did insist that Johnson double-check the computer’s calculations.

So who is this woman who played an important but largely unknown part of such a well-known historical event? During her long life, she was a wife, a mother, an African-American, a teacher, and a human computer, a term rarely used these days. Her calculations played a part in much of early spaceflight and in 2015, she was awarded the Presidential Medal of Freedom by President Obama. She also has a building named after her at the Langley Research Center in Hampton, Virginia.

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Friday Hack Chat: Everything PCB

February 28, 2018 by 14 Comments

It was not too long ago that all PCB design packages were proprietary. Getting PCBs made was expensive, and if you tried to do this over the Internet, the best way was to download a board house’s proprietary software, design your board in their software suite, and send your boards off to be made. A 5 cm square board would cost two hundred dollars. I know this to be true because I’ve said it before, and no one has corrected me.

For this week’s Hack Chat, we’re talking Everything PCB with OSH Park. OSH Park is the leading creators of perfect purple PCBs. They have POGs, and for the last two weeks, they’ve been one of the few places you can send some Gerbers to and have it manufactured in a timely manner if you live in the US. Because China was closed.

For this week’s Hack Chat, we’re going to be talking about everything PCB. How do you do castellated holes? How do you mill slots and square or otherwise non-round holes? Internal cutouts? Stop mask expansion? Artwork? Panelization? Why purple? More POGs!

Our guests for this chat will be [Dan Sheadel] and [Drew Fustini] of OSH Park, and they’re going to be there answering all your questions. [Dan] has been around OSH Park from the beginning and enjoys designing tiny useless robots and mentoring students building better ones. [Drew] is an Open Source hardware developer, firmware designer, a BeagleBoard board member, and is usually found at hardware meetups wearing purple.

join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat is going down Friday, March 2nd at noon, Pacific time. Want to know what time this is happening in your neck of the woods? Have a countdown timer!

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.

Detoured: Fabbing At The Art Institute Of Chicago

February 28, 2018 by 11 Comments

[Majenta Strongheart] is one of the talented folks who works at the SupplyFrame Design Lab, home to dozens of Hackaday meetups, the Hackaday Superconference, and when the shop floor isn’t filled with chairs, is the place where tons of awesome projects are fabricated. [Majenta]’s role at the Design Lab is a Staff Designer, where she’s responsible for working the machines, and holds the distinction of being in the room when the SawStop kicked for the first time. Don’t fret: it was mirrored acrylic.

Among [Majenta]’s other duties at the Design Lab is on the social media front, showing off the capabilities of other design spaces around the country. Her first video in this series is from her alma mater, the Art Institute of Chicago. In this video, [Majenta] takes a look at the incredible fabrication facilities found here.

The tour begins in an exceptionally well-equipped wood shop kitted out with panel saws, spindle sanders, bandsaws, and not enough clamps. From there, the tour moves over to the metal shop and — unique for the city of Chicago — a forge. A long time ago, after Philadelphia and New York were the tech centers of America, and before the Bay Area was the tech center of America, Chicago made everything. The forge at the Art Institute of Chicago is the last remaining place in the city where metal casting takes place. This space was grandfathered in, and still remains a place where students can cast objects out of bronze and aluminum.

The Art Institute of Chicago is a very, very well equipped space full of enough tools to make anything you want. If you’re looking for some inspiration on what your basement, garage, or local hackerspace should look like, you need only look at [Majenta]’s tour. You can check out the entire video below.

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Building A Portable Solar Powered Spot Welder: Charging Supercapacitors

February 28, 2018 by 48 Comments

Before Lunar New Year, I had ordered two 3000 F, 2.7 V supercapacitors from China for about $4 each. I don’t actually remember why, but they arrived (unexpectedly) just before the holiday.

Supercapacitors (often called ultracapacitors) fill a niche somewhere between rechargeable lithium cells and ordinary capacitors. Ordinary capacitors have a low energy density, but a high power density: they can store and release energy very quickly. Lithium cells store a lot of energy, but charge and discharge at a comparatively low rate. By weight, supercapacitors store on the order of ten times less energy than lithium cells, and can deliver something like ten times lower power than capacitors.

Overall they’re an odd technology. Despite enthusiastic news coverage, they are a poor replacement for batteries or capacitors, but their long lifespan and moderate energy and power density make them suitable for some neat applications in their own right. Notably, they’re used in energy harvesting, regenerative braking, to extend the life of or replace automotive lead-acid batteries, and to retain data in some types of memory. You’re not likely to power your laptop with supercapacitors.

Anyway, I had a week-long holiday, and two large capacitors of dubious origin. Sometimes we live in the best of all possible worlds. Continue reading “Building A Portable Solar Powered Spot Welder: Charging Supercapacitors” →