Monthly Archive: April 2009

A Foot in the QRSS Door

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I’ve been unbelievably busy over the past couple weeks. Last Thursday my boss approached me and asked if I could work over the weekend. He wanted to complete and submit a grant by the deadline (Monday at 5pm). Scientific research grants are not easy to prepare. ~40 pages of forms to fill out, biographies to design for each of the lab workers, budget appropriation plans, animal handling protocol approval forms, plus 12 pages of scientific dialogue explaining the experiment. Now, I know that it may not sound like much, but trust me – it’s a very dense (11 and 9pt Arial font, single spaced) paper which takes about 2.5 hours for me to read from start to finish. Being the only native English speaker in the laboratory, I’m expected to assist in the polishing of its dialogue, as well as thoroughly evaluate its scientific content and offer suggestions. To make a long story short, I worked really hard (really long days) on Friday, Saturday, Sunday, and Monday to accomplish this. Monday afternoon when it was done (at about 4pm) I went home and collapsed in exhaustion. I don’t know how my boss does it! He worked on it far more …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-30-a-foot-in-the-qrss-door/

Someone Ghettoer Than Me?

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Apparently I’m not the only person out there who gets their kicks from ghetto-rigging electronics. I’ve been known to build integrated circuit-powered devices into empty disposable pipette boxes , construct regulated power supplies fixed to Jenga blocks , Build server-style PCs into haphazardly-decorated wooden boxes , plexiglas containers, and even gas tanks which probably isn’t even a safe thing to do , and cram printer servers into used paper boxes . Heck, even my brief excursion into wardriving relied on 100% ghettorigged equipment. Although I did use a hot glue gun to repair a broken monitor back in 2004 , I’ve underestimated the power of hot glue in the development of ghettorigged devices. Although I’ve done a lot of random things over the years, I have to say CrazyTerabyte gets the cake. Maybe I’m being a little over-dramatic, but the truth is that while stumbling around the Internet this morning I came across First contact with ATmega8 microcontroller – part 2 in which a small circuit was held together by hot glue! [pictured] I saw this and my mouth dropped open. “That’s amazing!” It’s so simplistic, so rapid-development-style, so convenient, so shotty – it’s the very embodiment of the spirit …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-25-someone-ghettoer-than-me/

Puxing 777 Radio Headset Schematic

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I successfully created a speaker/microphone/transmit button circuit for the puxing 777 which probably works for all puxing radios. Instead of simply using circuits found on other websites (always for other radios), I decided to reverse-engineering an earphone/microphone headset that came with the radio to determine how it worked. I can’t claim that I’m an expert in electronics theory, but I can say that I faithfully rebuilt the circuitry within the factory-shipped headset and it worked. The result allows me to leave my handheld radio in its charger while casually listening/transmitting with a button that I made instead of having to reach around and awkwardly squeeze the transmit button on the side of the radio. Once again, I built this circuit and it was successful for me, but there may still be a better way to do it. The microphone is a 20-cent electret microphone with no special modifications. The speaker I used is a standard 8ohm loudspeaker with no special modifications. The switch is a keyboard-style (push-to-talk) switch, and the capacitor I used is good for 10nF. If you have any ideas for improvements, let me know! I’ll post some photos once I have my completed little “base station” set …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-22-puxing-777-radio-headset-schematic/

DIY Morse Code Keyer

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Over the last couple weeks whenever I had the time I’d work on creating a little DIY morse code keyer. After 6 designs (whoa!) I came up with the winner. The youtube video describes it all I guess. Basically it just uses a bar of aluminum which rocks on a metal pin. Thumb-screws on each side of the balance point (fulcrum?) can be adjusted to modulate the distance the paddle has to go down to be activated, and how high the paddle goes up when released. A couple springs (one pull-type and one push-type) help give it a good bounce between keys. Two potentiometers (knobs) control volume and frequency. I especially like the ability to control the frequency! A capacitor inline with the speaker helps smooth the output a bit too. It’s not professional, but hey – for a couple bucks of parts I made a functional keyer and had a blast doing it. Now I guess I should learn Morse code… And some photos…

Permanent link to this article: http://www.SWHarden.com/blog/2009-04-20-diy-morse-code-keyer/

Irreversible Geekdom

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Yes I’ve taken yet another plunge into the geek world by becoming a licensed amateur radio operator. My wife and I both took our technician exam last week (and passed), and this morning I discovered that our call signs have been processed. I’m KJ4LDF, she’s KJ4LDG. I’m a little disappointed that my call sign has an “F” in it. On the air, “F” and “S” sound similar, so I’m more likely to have people asking me to repeat it. The phonetics are Kilo, Juliet, Four, Lima, Delta, Foxtrot. Foxtrot! How lame is that? [sighs] Then let’s go to acronyms. LDF… “long distance fun”? Catchy and clever, but very gay sounding. [sighs again]. Either way, I’m glad I’ve been added to the database, and am now legally able to begin broadcasting on VHF/UHF. Beacon stuff (like I wrote about in the last post) would best involve lower frequencies, which would mean I have to take another exam to get a higher license class. Anyway, I’d better get back to work. Just wanted to share.

Permanent link to this article: http://www.SWHarden.com/blog/2009-04-15-irreversible-geekdom/

DIY Pointless Beacon Project

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I, Scott Harden, in my infinite restlessness and my limited sanity, hereby declare my next [potential] project. The idea is still in the earliest stages of development, and I have much to research (for example, I don’t even know if it’s legal) but it’s a cool idea and I want to try it. I know I’ll learn a lot from the project, and that’s what’s important, right? So, here’s the idea. I want to build an incredibly simple, low power radio transmitter that broadcasts data on a fixed frequency. Data is provided by (you guessed it) a picaxe chip! What data will it transmit? I’ll tell you! It could transmit… uh… err… um… okay it doesn’t really matter and I don’t even know, I just want to do this project! Maybe temperature and light intensity data or something. Who cares. Anyway, I want to put this whole deelibopper (temperature and light sensors, picaxe microcontroller, and transmitter) into a drybox (pictured). Once properly closed, this box will keep everything in pristine working condition by protecting against rain, heat, snow (not that we get much of that in Orlando), hurricanes, and perhaps even Florida panthers and bears (oh my). I’d make a …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-14-diy-pointless-beacon-project/

Molecules and Non-Steam Engines

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Early last week I did something surprising. Compelled by a newfound sense of freedom (I just graduated with my masters! yay!) and perhaps a little nostalgia, I decided to venture back into the psychotic world of CounterStrike. The game is quite old (released in 2000) but is a classic and is surprisingly well-furnished with online players. As I’m writing this, there are 33,125 (steam version) + 64,975 (version 1.6) = 98,100 players. That’s almost one hundred thousand players online this moment! Anyone who knows me can tell you that I’m not a big fan of paying for software. In the case of Microsoft products, they’re a necessity (sorry linux people – it’s true – it’s often needed), but they’re easy to download/install illegitimately so they’re free. Counterstrike is somewhat similar. However, it’s a little more difficult than most other softwares. Because of the nature of the program (using an internet-based master server to find lists of servers to connect to, and connecting to servers requiring identification etc) any server who wants to be legitimate can block users who aren’t. In other words, with a fresh-out-of-the-box server, non-legitimate counterstrike users can’t play (they must be steam-verified). In fact, it takes a …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-14-molecules-and-non-steam-engines/

Capacitor + LEDs + HDD = LOLZ

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I was poking around the internet looking at various ways people made smooth-fading LED circuits and I came across the site of a guy who did something pretty creative that made me smile. Before I got too far, I wanted to mention that I saw a ton of plans involving fading LED intensity utilizing 555 timer ICs, but for my purposes an in-line (series) capacitor before the LED should do fine. Here’s the site which documents the project. Basically it’s a skull with red LED eyes which glow in response to hard drive activity. The capacitor makes the eyes fade in and out smoothly, as opposed to the jerky on/off flashing of standard hard drive activity LEDs. Video of the project result (.6MB XVID AVI) shows the effect. Very clever!

Permanent link to this article: http://www.SWHarden.com/blog/2009-04-09-capacitor-leds-hdd-lolz/

I Spotted an Airplane!

I know this type of thing has probably been done countless times, but I’d like to provide my contribution to the world of Google Maps Anomalies. At the coordinates of 28.486942,-81.727869 I located an airplane flying over a lake in central Florida. The thing that impressed me was that the blades of the plane appear to be standing still. How fast was this image taken? This plane is moving well over a hundred miles an hour, but it’s crystal clear. You can almost make out the pilot too. How cool is that? If you want to try to see this plane yourself, go to google maps and just search for the coordinates I provided. Good luck!

Permanent link to this article: http://www.SWHarden.com/blog/2009-04-06-i-spotted-an-airplane/

Free Online Study Questions for Ham Radio Technician License

All right, here’s the scoop! I want to get my amateur radio license, but I’m a busy guy. I’ve decided to study from the pool of questions on the ARRL website. I downloaded the text version of the questions, wrote a python script to analyze it, and vwala! I generated a pretty and clean study guide that can be printed on 11 pages (double-sided), which is WAY better than the 120+ pages I would need if I printed their official PDF! Here you can download no-nonsense questions and answers for the Technician license exam. These questions should be valid through June 30, 2010 >>> HAM RADIO LICENSE STUDY GUIDE with answers marked >>> SELF-EXAM PDF where answers aren’t marked >>> An ONLIE VERSION has also been provided If you want you can see the python script I used to make these gorgeous documents.

Permanent link to this article: http://www.SWHarden.com/blog/2009-04-02-free-online-study-questions-for-ham-radio-technician-license/

Is Google Re-Indexing My Life?

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After several years of persistent writing on this website I was forced (by my undergraduate university’s difficult course loads) to stop adding to this blog – something I consider to be one of the most significant projects I’ve ever worked on, with brain-to-text recordings of my thoughts spanning almost a decade of time. After a few years of suspended writing, Google went from loving me (sending me thousands of pageviews daily) to forgetting about me (nothing. silence. nada.). Now that my thesis requirements have been completed, I’m trying to re-energize my writing in an attempt to document the projects I work on which, without this website, would likely be forever forgotten even by me. It appears that the burst of new writing has regained Google’s attention. Google for terms such as “data smoothing in python” and it favors my site. Google is slowly, but surely, re-indexing my pages and assigning them values of relevance which are approaching (but still a tiny fraction of) what they were before my hiatus. Here’s a chart from google’s analytics demonstrating an estimation of IP visits per day (visitors) and their locations. Do I have fans in South Africa? I didn’t know they had computers …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-02-is-google-re-indexing-my-life/

DIY 2meter Radio Antenna

I was poking around my digital camera’s SD card this morning and I stumbled upon a video I made a few weeks ago showing a little comparison between a rubber duck and a homemade 2m jpole antenna. Let me make a few things clear. When I built the jpole, I had ABSOLUTELY NO IDEA what I was doing. I’m not an antenna expert, I’m not a radio expert, I just get bored sometimes. The antenna has not been properly tuned. Yet, it works leagues better than my standard antennas. Even though its resonance properties leave much to be desired (untuned, remember?) I think its success has to do with its location. It’s on the balcony of my apartment, 3 stories in the air, and facing across Orlando (where most of the 2-meter repeaters are). The video itself isn’t that significant, but I wanted to post it so it doesn’t get forgotten.

Permanent link to this article: http://www.SWHarden.com/blog/2009-04-02-diy-2meter-radio-antenna/

Unlimited Freedom: Day 1

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Two hours after getting home from work I’m already basking in the newfound carefreeness thanks to the successful completion of my thesis defense (and graduation requirements). Yesterday I went to skycract, early this morning I posted a schematic diagram of a basic circuit concept for a radio/microphone interface box with tone generating functions, and this afternoon I finished its assembly. It’s hacked together, I know, but it’s a PROTOTYPE and is for functional use only. What does it do? It’s complicated, and I described it in the previous entry. It’s basically just an exercise in microchip programming! Here are some photos… Here’s that internal photo I promised I’d get posted yesterday… Here’s the little setup with the main control unit and a DC to DC regulated power supply / serial microchip programmer I made. Here’s the main control box. Notice the “2-way lighted switches” which I described in the previous entry (I posted the schematic). I found that proper grounding (floating pin prevention) was critical to their proper function. I’m still new to these chips, so I’m learning, but I’m making progress! Getting a little artsy with my photographs now… this is the core of the device. It’s a picaxe …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-01-unlimited-freedom-day-1/

Releasing the Bull

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I successfully defended my thesis yesterday, thereby securing the final facet of my degree requirements making graduation inevitable! A master’s in molecular biology and microbiology… Yeah, it sounds boring, but it is what it is – ya’ know? I indulged in a celebratory visit to Skycraft Parts and Surplus immediately after the successful defense, and spent the evening relaxing and winding-down after a stressful week of preparation. After a few hours of building, breaking, ghettorigging and accident-prone sodering, my wife and I had “breakfast” (french toast, pancakes, etc) at Denny’s at 11pm. Yes, what a relief. I will post more as to my current project in a later entry, but for now let me disclose the super-simple circuit diagram! I’m using a PICAXE 14M microcontroller to serve as an intermediate between my microphone and my ham radio. The goal is to use this device to control the “TALK” button, giving the option of a series of beeps before and after my talk (turned on/off by switches). Additionally, I’ve added two buttons. One of them will beep-out my call sign in Morse code when pressed (with the pitch of the beeps or the speed of the beeps set by a knob), …

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Permanent link to this article: http://www.SWHarden.com/blog/2009-04-01-releasing-the-bull/