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UMPC Adventures: the Mix Yoga

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A common theme in my life is unnecessarily small computers. Naturally when I heard that you could buy a metal-body UMPC for $450 I was intrigued. Thus began my journey with the Mix Yoga.
The Good
The Mix Yoga is a gorgeous little UMPC, and everything on it feels solid and well-built. It somehow has a heft to it that says "quality" while at the same time being just light enough to hold in your hand for extended periods. The keys are slightly cramped, but backlit and very satisfying to use. The screen is well-lit and very high resolution, having about 2000 pixels along the long axis. It is touch-enabled and supports an active stylus.
The Bad It's pretty buggy sometimes, and really not the fastest. Many people reviewing this computer will say that it's useless for anything more than one task at a time, but I didn't have that experience. I actually brought this to a hackathon and used it as my main computer when I forgot the charger for my main laptop, and it held u…

Transformers and the ZVS driver

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Incentive I've been looking for cheap, efficient ways to generate high voltage ever since I got interested in electronics. Ever since then, I've been looking for an easy, reproducible way to obtain various voltages and power levels for a number of different high voltage projects. I've found a number of methods, but never one that I could easily duplicate or apply to other situations to my satisfaction. Recently, I found out about the Mazili ZVS driver. It allows you to switch a center-tapped transformer at its resonation frequency, and can achieve impressive output powers and efficiencies. They are also available cheaply on ebay. I decided to pull the trigger and see what the fuss was about. After winding a couple of turns on a TV flyback and connecting everything up, I was greeted with a terrifying red-orange arc on the output wire similar to the device here
Experiments For my first experiment, I obtained some ferrite rods from ebay and 3D printed some spools to fit ar…

Smart LED Strips: Revisited

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As a present for my 1-year anniversary with my girlfriend, I decided to create an RGB mushroom with the same functionality as my smart LED strips, but with the additional option of being able to move it between wifi hotspots without having to reflash the firmware.

Smart LED strips using a Blynk Interface

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I recently decided that regular LED bulbs are too low-tech and non-computerized for my liking, so I decided to try designing a system that I could control remotely, for free, using smart WS2812 smart leds instead.

The Circuit I interfaced a small strip of 26 smart LEDs to an ESP8266 NodeMCU board via a 1K resistor, and powered the whole thing from a USB connection. Probably not a good idea at full power, so I made sure not to run the strip at full power. 
The Code The code for this circuit would be the most complex part, and I started by trying to get the ESP to control some smart LEDs. I did this by downloading adafruit's libraries and modifying their example code to do something really simple--wash some colors across the strip. This part of the code was pretty easy, although figuring out where the digital pin in the IDE linked to the physical pin was a little tricky. I found out that you could prepend a 'D' in front of the number to get the actual pin that was listed on …

Inductive Energy Transfer pt.1

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For the next version of my crystal necklace, I wanted the ability to transfer energy to the device wirelessly, so that I could pot it in silicone and make it waterproof. In order to do that, I threw together a quick experiment using my function generator and an oscilloscope. 
Design I quickly printed out two spools with a diameter of 20 mm and wrapped 50 turns of 26 gauge magnet wire around each.


I then threw together a mosfet switch on a breadboard, and connected it to my function generator. I tried different frequencies with the device, and found that it transmitted best at around 2.18 Mhz.


I didn't bother measuring the power transmitted because it was so small, but I did manage to get a red led to glow slightly. I think I'm going to need to research this area more before I build the next iteration, and figure out how to push more power through.


The Wearable Computer--A Synopsis

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Having been obsessed with computers since middle school, I've always dreamed of the day I could bolt one to my face. In high school, I built what would become the prototype of all the wearable computing shenanigans I would build in college.
Iteration 0 You might remember those wild planet remote-controlled toy cars that had video cameras and glasses that could display the video transmission. Thanks to hackaday, I found an article on how to hack them and turn them into NTSC video HMDs. It generated video with an arduino, and used an LM386 chip to obtain and graph the ambient electrical field intensity oscilloscope-style. Everything was mounted around my neck in a pelican case that I mutilated for the purpose. Disregard the milk, I was in ihop. CPU: 16Mhz arduino nanobattery: 2-cell 800 mAh LiPodisplay: 300x240 monochrome monoclecomfortable wear period: 4 hoursmobility: joggingperipherals: LM386 EMF detector Iteration 1 Interestingly enough, a good portion of my inventions come from…

The Cyberstrike

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I'm a college student, and a game that some of us like to play is a game called HvZ. Since I also enjoy doing electronics projects, I decided that I'd mod a nerf rapidstrike into something with a little more punch. as I began taking apart the gun, I noticed something unusual.

The buttons were useless. They fell apart as soon as I exerted any force on them at all.
So I decided to gut it and use power electronics for all the switching!
The gutted rapidstrike. Notice the high voltage transformer in the top-left. Another post for another time. THE POWER ELECTRONICS
I decided that I'd use the IRFP260N hexfet by Linear because I had a bunch of spares floating around my parts bin. In order to save space, I found a neat dual channel low-side fet driver chip called the ICL7667 by Intersil. After adding some diodes and capacitors to cut down on the transients, I soldered the circuit up. 

Not my best soldering job (the perf boards I was using were probably the cheapest boards I've ev…