High Voltage: Lightning Simulator Can’t Send You Back To The Future

August 23, 2011 by Jack Buffington 21 Comments

Continuing on with our high-voltage theme, today we have a page describing Marx generators by [Grenadier]. Marx generators are devices that produce pulses of very high voltage with fast rise times. For most of us, that means that they can make neat sparks. For the more serious types out there, that also means that they are great for driving some high-powered lasers, simulating lightning strikes, and even igniting the conventional explosives surrounding the core of a nuclear weapon! His page includes a video of his Marx generator producing some pretty sparks for those of us who aren’t so serious.

We have featured several of [Grenadier’s] projects in the past. This one doesn’t deviate from his normal style of taking a subject and clearly describing it with lots of well-taken pictures.

Recently, he has been working on improving one of his projects that deviates from what he normally does. He is calling it “The Junkbox”. The Junkbox is something like a free online swap meet where you can sell your electronic parts.

Video: Shocking [Jack] Into Submission With High Voltage

August 22, 2011 by Jack Buffington 59 Comments

Hackaday headquarters has recently been overrun by techno-groupies hanging around outside so we decided to take some measures to discourage that. A word of warning though, if last week’s video ruffled your feathers then you probably shouldn’t watch this one. In this video [Jack] shows you how to create a stun glove using a disposable camera and some leather spikes. To prove that it really works, he intentionally takes a jolt from it courtesy of Hackaday’s security chief [Vlad].

Check out the video after the break.
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Basic Animatronics Continued: Servo Actuated Mouth

August 21, 2011 by Jesse Congdon 4 Comments

[Chris] is at it again and this time he has put together a tutorial rounding off his animatronic face by actuating the mouth. His tutorial covers two different styles of robot mouth: an LCD mouth which dims to imply actuation and a servo articulated flap.

[Chris] covers all the aspects of each mouth type, from the basics of human mouth actuation to servo motor control. In this case the LCD mouth is not quite as impressive so it gets installed on a face mock up while the servo mouth goes on the face previously featured in his other tutorials. The entire setup is still controlled using a single PIC 18F452. The circuit diagrams and code for both types of mouth are all available on the site including videos of the actuated mouth and a gif of the LCD mouth in action.

Check out a video of the articulated mouth below throwing down some classic season 6 Jean-Luc. If you are interested in the other parts of the face we have covered [Chris]’s other tutorials on the eyebrows and the eyeballs. These are a great jumping point for your own animatronic face project and do a great job of setting up all the know how you’d need to build your own emotional puppet.

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MilliOhm Measurement Made Easy

August 17, 2011 by Nick Schulze 8 Comments

When [Kerry] wanted to measure some very small resistances very accurately he did not want to fork out the big bucks for a high end multimeter or a mico-ohmmeter, so he decided to build one himself. Measuring resistance is a simple enough concept, it directly implements Ohms law (V=IR). The problem with very small resistances is that when you apply a sensibly sized constant current to the load, the voltage to be measured is too small for conventional multimeter.

To overcome the problem [Kerry] designed a constant current source of very high accuracy using the AD8276 unity gain difference amplifier and the AD8603 high precision opamp. Then to boost the voltage across the load he used the LMP8358 programmable gain precision opamp, this allowed him to easily change the gain for different magnitude resistance, the circuit diagrams are all available on his site. Finally he used four point probes to eliminate probe wire resistance errors, ending up with the ability to measure small resistances with very high accuracy.

Eye See You.

August 14, 2011 by Nick Schulze 13 Comments

So you want to add animated eyes to your next robot? Now you can.. Using ping-pong balls, some scrap plastic and 6 servo motors [Chris] has created these animatronic eyes along with some nifty animated eyebrows. To get motion emulating realism [Chris] created a 2 axis gimbal using plastic rings and some nuts and bolts. The eyes (ping-pong balls) are held in the gimbal and actuated using two servos each. The eyebrows use another pair of servos and some tubing covered in electrical tape as the actual eyebrow.

[Chris] Kindly goes through the entire build process including information for beginners such as servo motor control. The whole thing is controlled using a PIC 18F452 and circuit diagrams and code are all available on the site. Check out the video after the break to see the eyes in action, you will also find more videos describing the build process if you follow through the tutorial.

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Build Your Own Class AB Audio Amplifier

August 14, 2011 by Jeremy Cook 18 Comments

[Dino Segovis] wrote in to tell us about his “hack”, making an AB Audio Amplifier. The advantage of this particular amp is that the transistors never turn off, which would cause distortion. A full schematic is given in the article as well as a parts list. A complete “bill of materials” makes any circuit building project easier, especially for the beginner.

Although this is by no means a new circuit design, (a similar setup is used in car audio equipment) [Dino] does a great job of explaining how things work in the article itself and in the video after the break. He also gives some great tips about transferring your drawn circuit to a breadboard in a neat and organized way at around 5:00 in the video. Continue reading “Build Your Own Class AB Audio Amplifier” →

Installing Linux On A 386 Laptop

August 12, 2011 by Kevin Dady 121 Comments

The “cheap” and “easy” way in about an hour! A question that pop’s up from time to time is “I somehow ended up with an archaic old laptop / computer, can it run Linux?” Well of course it can, but that totally depends! On what? Well machine CPU, CPU speed, hard disk space, RAM and most importantly what you are expecting it to do.

Okay, why a Intel 386? Well number one I own a 386, but more importantly its the absolute bottom Intel CPU you can run Linux on. While it wont be able to do much, it will give you a basic system to kick around and “get to know” the insides of Linux without a million things installed and the worry of breaking it.

Unfortunately a 386 requires some special moves as the actual chip was dropped from almost all distributions long ago. All of the modern distributions I have looked at require at least a 486 CPU. This tutorial will be strictly for installing a basic bare bones Linux on a 386. Have a 486? Pentium? Faster? Never fear I will be covering that in a part II later this week.

Linux on a 386 in about an hour? Madness you might think, it probably takes Linux longer to boot on a 386 (and in some cases you are correct)! Want to know the trick? Simple, cheat!

Join me after the break for the parts and steps needed to get you started.

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