Circuit VR: Starting An Amplifier Design

August 10, 2018 by Al Williams 11 Comments

Sometimes I wish FETs had become practical before bipolar transistors. A FET is a lot more like a tube and amplifies voltages. Bipolar transistors amplify current and that makes them a bit harder to use. Recently, [Jenny List] did a series on transistor amplifiers including the topic of this Circuit VR, the common emitter amplifier. [Jenny] talked about biasing. I’ll start with biasing too, but in the next installment, I want to talk about how to use capacitors in this design and how to blend two amplifiers together and why you’d want to do that.

But before you can dive into capacitors and cascades, we need a good feel for how to get the transistor biased to start with. As always, there’s good news and bad news. The bad news it that transistors vary quite a bit from device to device. The good news is that we’ll use some design tricks to keep that from being a problem and that will also give us a pretty wide tolerance on component values. The resulting amplifier won’t necessarily be precise, but it will be fine for most uses. As usual, you can find all the design files on GitHub, and we’ll be using the LT Spice simulator.

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Big Power, Little Power, Tiny Power, Zap!

August 9, 2018 by Roger Cheng 4 Comments

Our Hackaday Prize Challenges are evaluated by a panel of judges who examine every entry to see how they fare against judging criteria. With prize money at stake, it makes sense we want to make sure it is done right. But we also have our Hackaday Prize achievements, with less at stake leading to a more free-wheeling way to recognize projects that catch our eye. Most of the achievements center around fun topics that aren’t related to any particular challenge, but it’s a little different for the Infinite Improbability achievement. This achievement was unlocked by any project that impressed with their quest for power, leading to some overlap with the just-concluded Power Harvesting Challenge. In fact, when the twenty Power Harvesting winners were announced, we saw that fourteen of them had already unlocked the achievement.

Each of the Power Harvesting winners will get their own spotlight story. And since many of them have unlocked this achievement, now is the perfect time to take a quick tour through a few of the other entries that have also unlocked the Infinite Improbability achievement.

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Friday Hack Chat: Motors Made Out Of PCBs

August 9, 2018 by Brian Benchoff 15 Comments

One of the most amazing technological advances found in this year’s Hackaday Prize is the careful application of copper traces turned into coils. We’ve seen this before for RFID tags and scanners, but we’ve never seen anything like what Carl is doing. He’s building brushless motors on PCBs.

All you need to build a brushless motor is a rotor loaded up with super powerful and very cheap magnets, and a few coils of wire. Now that PCBs are so cheap, the coils of wire are easily taken care of. A 3D printer and some eBay magnets finish off the rest. For this week’s Hack Chat, we’re talking with Carl about PCB motors.

Carl Bugeja is a 23-year old electronics engineer who is trying to design new robotics technology. His PCB Motor design won the Open Hardware Design Challenge and will be going to the Finals of the Hackaday Prize. This open-source PCB motor is a smaller, cheaper, and easier to assemble micro-brushless motor.

[Carl]’s main project, the PCB Motor is a stator that is printed on a 4-layer PCB board. The six stator poles are spiral traces wound in a star configuration. Although these coils produce less torque compared to an iron core stator, the motor is still suitable for high-speed applications. [Carl]’s been working on other PCB motor designs, like the Linear PCB motor which is a monorail on a PCB and the Flexible PCB actuator where the coils of wire are tucked inside Kapton.

During this Hack Chat, we’re going to be discussing:

The design and construction of brushless motors
How to drive these motors
PCB applications beyond standard circuitry
Building accessible robotics technology

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Hack Chat Event Page and we’ll put that in the queue for the Hack Chat discussion.

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week is just like any other, and we’ll be gathering ’round our video terminals at noon, Pacific, on Friday, August 10th. Need a countdown timer? You wouldn’t if we switched to universal metric time.

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.

Ask Hackaday: Is There A Common Mechanical Parts Library?

August 8, 2018 by Dan Maloney 45 Comments

Like many stories, this one started on the roof. This particular roof is located in Michigan and keeps the rain and snow off of the i3Detroit hackerspace. Being an old industrial building, things up on the roof can start getting creaky, and when an almighty screech started coming from one of the rooftop vents as it swiveled in the wind, Nate, one of the group’s coordinators, knew it was time to do something about it.

Previous attempts to silence the banshee with the usual libations had failed, so Nate climbed up to effect a proper repair with real bearings. He dug into the unit, measured for the bearing, and came down to order the correct items. That’s when it struck him: How many should I order? After all, bearings are useful devices, not just to repair a wonky vent but especially handy in a hackerspace, where they can be put to all sorts of uses. Would extra bearings be put to good use, or would they just sit on a shelf gathering dust?

That’s when Nate dropped us a line and asked a question that raises some interesting possibilities, and one which we couldn’t answer offhand: Is there a readily accessible online library of common mechanical parts?

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Video Quick Bit: Power Harvesting Hacks

August 7, 2018 by Brian Benchoff 5 Comments

Majenta Strongheart is back again, this time taking a look at some of the coolest power harvesting projects in this year’s Hackaday Prize.

The entire idea of the Power Harvesting Challenge is to get usable power from something, be it solar energy, a rushing waterfall, or fueling steam turbines with hamsters. [Cole B] decided that instead of capturing energy from one of these power sources, he’d do it all. He created Power Generation Modules, or Lego bricks for harvesting power. There’s a hand crank module, a water turbine module, and enough modules to do something with all that captured power like a light module and a USB charger module.

But maybe you don’t want to generate power the normal way. Maybe you think spinning magnets is too mainstream, or something. If that’s the case, then [Josh] has the project for you. It’s the P Cell, a battery fueled by urine. Yes, it’s just a simple copper zinc wet cell using urea as an electrolyte, but remember: in the early 1800s, human urine was a major source of nitrates used in the manufacture of gunpowder. Why not get some electricity from something that is just sent down the tubes?

Right now we’re in the middle of the Human Computer Interface Challenge. Show us that you have what it takes to get a computer to talk to a human, get a human to talk to a computer, or even recreate one of those weird 3D CAD mice from the early 90s. We’re looking for any interesting ways to bridge that valley between people and their devices. Twenty Human Computer Interface Challenge submissions will be selected to move onto the finals and win $1000 in the process! The five top entries of the 2018 Hackaday Prize will split $100,000!

Recorded Programming — Thanks To Bing Crosby

August 7, 2018 by Al Williams 17 Comments

If you look up Bing Crosby in Wikipedia, the first thing you’ll notice is his real name was Harry. The second thing you’ll read, though, is that he is considered the first “multimedia star.” In 1948, half of the recorded music played on the air was by Bing Crosby. He also was a major motion picture star and a top-selling recording artist. However, while you might remember Bing for his songs like White Christmas, or for his orange juice commercials, or for accusations of poor treatment from his children, you probably don’t associate him with the use of magnetic tape.

In a way, Bing might have been akin to the Steve Jobs of the day. He didn’t power the technology for tape recording. But he did see the value of it, invested in it, and brought it to the market. Turns out Bing was quite the businessman. Want to know why he did all those Minute Maid commercials? He was a large shareholder in the company and was the west coast distributor for their products. He also owned part of the Pittsburgh Pirate baseball team and other businesses.

So how did Bing become instrumental in introducing magnetic tape recording? Because he was tired of doing live shows. You see, in 1936, Crosby became the host of a radio variety show, The Kraft Music Hall. This very popular program was live. That means you have to show up on time. If you go off on a tangent, you’ll run out of time. And if you make a mistake, there is no editing. Oh and one other thing. You have to do a nationwide live show twice: once for the east coast and another for the west. This was cutting into Bing’s “family time” which, as far as we can ascertain was a code phrase for golf.

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The Square-Inch Project Rides Again!

August 7, 2018 by Elliot Williams 37 Comments

Want to play a game? Your challenge is to do something incredible with a printed circuit board that measures no more than one inch by one inch. It’s The Return of the One Square Inch Project and it’s going to be amazing!

We can’t believe that it’s been three years! The original One Square Inch Project was a contest dreamt up by Hackaday.io user [alpha_ninja] back in 2015, and we thought it was such a great idea that we ponied up some prizes. The entries were, frankly, the best we’ve ever seen. So we’re doing it again!

Last time around, the size constraint focused the minds and brought out the creativity in some of the best and brightest of Hackaday.io. What functionality or simply amusement can you pack into a square PCB that’s just a tad over 25 mm on a side? We’d like to see.

We’ll be featuring entries throughout the contest. We think geek ‘cred is the best reward but if you want something more to sweeten the pot here you go:

Grand Prize:
- $500 Cash!
Four Top Entries Win Tindie Gift Certificates:
- Best Project – $100
- Best Artistic PCB Design – $100
- Best Project Documentation – $100
- Best Social Media Picture or Video – $100
Five Runner-Up Entries:
- $100 OSH Park gift cards

Want some inspiration? Last time the winner was a quadcopter in one square inch, but there were tons of useful and amusing projects crammed into tight quarters, and many of them transcend their constraints. There were not one but two hi-fi sound cards: one for your laptop’s USB port and one for your microcontroller projects that is now officially supported by the Teensy Audio Library. Need a MPPT power converter for a small solar project? How about a plug-load meter that fits on a US mains plug or an I2C to WS2818 converter to make blinking easier?

There were breakout boards for nearly every imaginable chip, a radio downconverter from our own [Jenny List], and a great magnetic rotary encoder design. Key Pass, an Arduino in the size of a DIP-8, and of course a bat detector, a bubble display volt meter, a smart watch, and a capacitive touch wheel.

It’s been three years, and parts have gotten cheaper, smaller, and more capable. What’s newly feasible in a square inch that wasn’t way back in 2015? Show us what you got.