Circuit VR: Sink Or Swim With Current Sources

May 3, 2018 by Al Williams 22 Comments

If you got your start in electronics sometime after 1980 your first project might well have been to light up an LED. Microcontroller projects often light up an LED, too, and a blinking LED is something of the “hello world” program for embedded systems. If you tried lighting up your LED with a 9 V battery directly — not that you’d admit to it — you found it would light up. Once, anyway. The excess current blows up the LED which is why you need a current-limiting resistor. However, those current limiting resistors are really a poor excuse for a current source or sink. In many applications, you need a real current source and luckily, they aren’t hard to create.

As always with Circuit VR, we’ll be using LT Spice to examine the circuits. If you need a quick tutorial, start here and come back after that. If you use Linux, don’t be dismayed. I run LT Spice under WINE and it works great. You can find all the Spice files on GitHub.

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San Francisco: Let’s Learn To Build Some Robots!

May 3, 2018 by Mike Szczys 1 Comment

Hone your skills at basic robot building. You’re invited to join Hackaday for a Beginner Robotics Workshop on Saturday, May 12.

For this workshop we’re pairing up with FIRST robotics mentors and students from the Bay Area. FIRST is an international high school robotics competition and you won’t believe what these teams can do. The workshop will start with an overview of the three major parts that go into a robot project: mechanical design, electronic design, and programming. From there, choose one of the three you want to focus on for the afternoon and let the hands-on fun begin as we break out into small groups to tackle some robotics problems!

The mechanical group will explore robot building using OnShape CAD software. The electronic group will work hands-on with Arduino-based prototyping and breakout boards. The programming group will utilize the Arduino IDE. Workshops will wrap up with a group discussion of how these three concepts are integrated in a single robotics effort.

Right now the Robotics Module Challenge of the 2018 Hackaday Prize is in full swing. We’re excited to see more roboticists in the world and are happy to bring you a workshop that is both technical and accessible. Come build some ‘bots and take home some new knowledge to pour into your project, and your Hackaday Prize entries!

Smooth PLA Through The Fire And Flames

May 3, 2018 by Lewin Day 17 Comments

3D printing makes it easy to produce complex geometries, but the fused deposition methods generally create parts with poor surface finish, largely due to the layers being highly visible in the finished part. There are a wide variety of ways to deal with this, often involving sanding parts after production, or the use of fillers and paints. [XerotoLabs] has another solution. (YouTube, video below the break.)

To smooth the parts, a butane torch is pressed into service. The flame temperature is kept fairly low, and the torch is used almost like a brush to evenly apply heat to the surface of the part. As the PLA reaches its melting temperature, surface tension helps to smooth the part out. This is very similar to flame polishing which is commonly used in the fabrication of acrylic plastics.

It is a technique that requires some finesse – too much heat or focus on a single area, and you’re liable to end up with a molten plastic blob instead of a nice shiny finished part. Precautions must also be taken to avoid burning yourself or your workshop to the ground. But it’s a useful tool to have in your kit when you’re producing PLA parts that you want to look their best.

We’ve seen other techniques for smoothing PLA, too – the solvent method is particularly interesting. Continue reading “Smooth PLA Through The Fire And Flames” →

3D Printering: Which Raspberry Pi Is Best At Slicing In Octoprint?

May 3, 2018 by Tom Nardi 22 Comments

OctoPrint is arguably the ultimate tool for remote 3D printer control and monitoring. Whether you simply want a way to send G-Code to your printer without it being physically connected to your computer or you want to be able to monitor a print from your phone while at work, OctoPrint is what you’re looking for. The core software itself is fantastic, and the community that has sprung up around the development of OctoPrint plugins has done an incredible job expanding the basic functionality into some very impressive new territory.

RAMBo 3D controller with Pi Zero Integration

But all that is on the software side; you still need to run OctoPrint on something. Technically speaking, OctoPrint could run on more or less anything you have lying around the workshop. It’s cross platform and doesn’t need anything more exotic than a free USB port to connect to the printer, and people have run it on everything from disused Windows desktops to cheap Android smartphones. But for many, the true “home” of OctoPrint is the Raspberry Pi.

As I’ve covered previously, the Raspberry Pi does make an exceptional platform for OctoPrint. Given the small size and low energy requirements of the Pi, it’s easy to integrate into your printer. The new Prusa i3 MK3 even includes a header right on the control board where you can plug in a Raspberry Pi Zero.

But while the Raspberry Pi is more than capable of controlling a 3D printer in real-time, there has always been some debate about its suitability for slicing STL files. Even on a desktop computer, it can sometimes be a time consuming chore to take an STL file and process it down to the raw G-Code file that will command the printer’s movements.

In an effort to quantify the slicing performance on the Raspberry Pi, I thought it would be interesting to do a head-to-head slicing comparison between the Pi Zero, the ever popular Pi 3, and the newest Pi 3 B+.

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More Details On That First Home-Made Lithographically Produced IC

May 3, 2018 by Jenny List 19 Comments

A few days ago we brought you news of [Sam Zeloof]’s amazing achievement, of creating the first home-made lithographically produced integrated circuit. It was a modest enough design in a simple pair of differential amplifiers and all we had to go on was a Twitter announcement, but it promised a more complete write-up to follow. We’re pleased to note that the write-up has arrived, and we can have a look at some of the details of just how he managed to produce an IC in his garage. He’s even given it a part number, the Zeloof Z1.

For ease of manufacture he’s opted for a PMOS process, and he is using four masks which he lists as the active/doped area, gate oxide, contact window, and top metal. He takes us through 66 different processes that he performs over the twelve hours of a full production run, with comprehensive descriptions that make for a fascinating run-down of semiconductor manufacture for those of us who will never build a chip of our own but are still interested to learn how it is done. The chip’s oblong dimensions are dictated by the constraints of an off-the-shelf Kyocera ceramic chip carrier, though without a wire bonding machine he’s unable to do any more than test it with probes.

You can read our reporting of his first announcement, but don’t go away thinking that will be all. We’re certain [Sam] will be back with more devices, and can’t wait to see the Z2.

Playing Jedi Mind-Tricks On Your TV

May 3, 2018 by James Hobson 4 Comments

Gesture-enabled controls mean you get to live out your fantasy of wielding force powers. It does, however, take a bit of hacking to make that possible. Directly from the team at [circuito.io] comes a hand gesture controller for Jedi mind-trick manipulation of your devices!

The star of the show here is the APDS-9960 RGB and gesture sensor, with an Arduino Pro Mini 328 doing the thinking and an IR transmitter LED putting that to good use. The Arduino Sketch is a chimera of two code examples for IR LEDs and the gesture sensor — courtesy of the always estimable Ken Shirriff, and SparkFun respectively.

Of course, you can have the output trigger different devices, but since this particular build is meant to control a TV the team had to use a separate Arduino and IR receiver to discover the codes for the commands they wanted to use. Once they were added to the Sketch, moving your hand above the sensor in X, Y or Z-axes executes the command. Voila! — Jedi powers.

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Raspberry Pi Is Up Up And Away

May 2, 2018 by Al Williams 3 Comments

BACAR — Balloon Carrying Amateur Radio — is just what it sounds like. A high-altitude balloon carries experiments and communicates via amateur radio. [ZR6AIC] decided to fly a payload in a local BACAR experiment. The module would send its GPS position via the APRS network and also send a Morse code beacon every seven minutes. It also sends other data such as temperature, and has an optional camera fitted.

The hardware used was the ubiquitous Raspberry Pi along with an associated daughterboard for transmitting on the 2 meter ham band. An RTL dongle took care of the receive portion and another dongle provided GPS. A DS18B20 temperature sensor provides the temperature data.

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