I recently inherited several tools and and pieces of equipment which I hope to put to good use someday. For now though, I live in an apartment, which means much of this stuff is going into storage. Some of the equipment is heavy and prone to damage, so I need a way to protect it. I decided to to build some small crates for these items, since cardboard boxes won’t be strong enough. However, I don’t want to spend a lot of money doing it, and lumber is expensive, so I figured I’d get what I need from old pallets. They’re a popular source of upcycled wood for DIY projects, which means there’s lots of info on how to reuse them, and best of all, they’re free. Last weekend I set about transforming some old pallets into crates and I’m quite happy with the results.
I love headphones. It’s the only way I can listen to music much of the time; without them I wouldn’t be able to. At work I listen on Grado SR-80’s, which allow external sound to come through so I can still hear my phone ring and be aware of what’s happening around me. At home, I wear closed phones like my Ultrasone HFI-580’s so I don’t have to hear what’s happening around me, allowing me to enjoy my music and movies in peace. With all of this headphone listening, it was inevitable that I would eventually take an interest in headphone amplifiers, and I did. Recently, I built the Objective2 headphone amplifier (actually, I built two – for home and work) and in this article I’ll cover what led me to the Objective2 amp and my experience building it.
Last week, I bought something I’ve wanted for quite some time: an oscilloscope. I’ve been doing more projects where a scope would be useful, such as audio amplifiers, PWM, and AC-DC rectification. And besides that, oscilloscopes are just plain cool. Of course, a scope by itself isn’t much fun, it needs something to measure. Something like an AC sine-wave, or an audio signal, or maybe… a person’s pulse rate? It’s possible, with the right sensor. Sean Michael Regan shows us how in the latest MAKE Weekend Project. I knew right away that it was perfect for trying out my scope. It was a bit of work, primarily because I modified the circuit, but the finished sensor is a lot of fun, and there is a lot of potential for doing more with it.
I built my first cMoy earlier this year, and it came out really great for my first attempt at building a headphone amp. The only problem was that it’s a poor match for the headphones I use. My headphones are all efficient low-impedance models (Grado, Ultrasone) that don’t require a lot of voltage. What they need is more current. The basic cMoy design doesn’t provide this, at least not with the OPA2132A OpAmp. I soon learned though that several DIYers have built similar “cMoy-esque” amps based on the circuit used in Grado’s RA1 headphone amplifier, which uses an NJM4556 (aka JRC4556) OpAmp, good for 70ma of current per channel. I decided to try building one, and I wanted it to be a little different. So I built it in a cigar box.
There was quite a bit of drilling and cutting involved, and I destroyed a couple boxes in the process. The volume knob is installed where the cigar maker’s medallion was previously located, which had their logo. For the circuit, I took some ideas from both the cMoy and the RA1 clones. I used some pretty high-end hardware, such as the Neutrik locking 1/4″ jack. It wasn’t because I thought it was necessary, but because it was easy to mount to the cigar box.
The result? Not very good. It’s unique, and looks interesting, but it doesn’t work very well. I ended up building two of them, and both are very noisy. Copper shielding on the second build helped, but not a lot. It might be all of the wiring needed to connect everything, or just the result of a poorly engineered DIY project based around a potentially “cranky” OpAmp, but it just isn’t a great amp. So I’ve kept the second one as a “show piece” while the first gets picked away at for spare parts. Even though it was ultimately a failed project, I’m glad I attempted it. For my next headphone amp, I’ll be using a professionally-engineered and designed circuit based around a PCB which should help ensure success.
I’m a big fan of the Playstation video game consoles, so when I learned about the PS2X library by Bill Porter, I had to try it out. PS2X makes it easy to interface Arduino microcontrollers with Playstation 2 controllers. After wiring everything up and testing it with the sample program, I set out to find something more interesting to do with it. The result is a stepper motor that is controlled by the Sony controller. Here’s a video of it in action:
At some point while researching microcontroller projects, I came across several people who had used Arduinos and PICs to drive analog panel meters so they would display computer stats such as CPU load, memory usage, etc. It immediately struck me as something I just had to do. Here it is. My PC meter uses an Arduino microcontroller and receives the stats from a .NET Framework application I wrote in C#.Net. It’s housed in a plastic enclosure and looks quite professional IMHO. It was a fun project, and something I think most any computer/electronics geek would enjoy. I love mine, and I look forward to building more.
Here it is in action:
Read on for details on the parts and tools I used, some info on the process of building the device (and the problems I ran into) and links to download the source code and meter templates.
Oftentimes, I find myself going to my parents’ house or a friend’s place to build or repair something, and I have nothing to put my larger tools in. As a result, my drill, saw, clamps and other large items end up either laying on the floor of my truck or stuffed into whatever cardboard box I found laying around. If I had a large, sturdy box to throw this stuff in, it would make these trips much more convenient and I would spend less time loading and unloading my tools and more time working. So when I saw Len Cullum’s Japanese Toolbox project in MAKE 34, I knew I had found my solution.
While testing my recently acquired Piranha LEDs, I noticed quite by accident that the output from the breadboarded circuit created some interesting effects when used to cast shadows against a plain background. The edges of the shadows show the red, blue and green (and mixed) colors due to their coming in from slightly different positions and angles. It’s a fun effect, but there isn’t much room for creativity as my test circuit only had 6 LEDs (2 of each color) grouped closely together. Something more interesting and dramatic could be achieved using larger light sources positioned further apart, which would allow control over where the different colors fall and how much they overlap. It’s something I may pursue in the future when I have more lights built. Until then, here’s a couple photos I snapped and a video I quickly put together using my test circuit.
The first photo is (quite obviously) my hand and the second is a failed amplifier circuit I had laying around.
And a video, which came out creepier than I had intended. A friend described it as “Dr. Frankenstein visits Studio 54!”
I’m planning an LED floodlight project that will use a lot of square 4-pin LEDs, aka SuperFlux or “Piranha” LEDs. I hadn’t had a chance to use these type of LEDs until now, so after receiving my order this week I immediately went to work on trying them out. This won’t be a very technical review, just a quick look at the specs and my experience with testing the LEDs and what I thought of them.
The cMoy Headphone Amplifier is a popular, well-documented DIY project, which makes it great for beginners to take on. That’s exactly the reason I chose to do it. I followed the instructions and suggestions from the TangentSoft cMoy Tutorial written by Warren Young, and it came out great, especially for my first attempt at building a headphone amplifier.
I won’t get into how I built mine (the tutorial at TagentSoft is where you should go for that) but read on if you’re interested in seeing what parts I used and some of the problems I ran into.