Archive for month: February, 2011

Hershey Vector Fonts

February 28, 2011 | Computer Graphics, My Projects | By: Mark VandeWettering

Nearly thirty years ago, I remember hacking together some simple code to display graphics on a WYSE 35 terminal. The terminals supported the TEK 4014 graphics commands to draw vectors, and I found the original “Hershey Fonts”, created by A.V. Hershey at the U.S. National Bureau of Standards, and placed in the public domain. I’ve […]

Pixels Past Circuit Boards

February 27, 2011 | Link of the Day | By: Mark VandeWettering

I’ve done a couple of Atari 2600 projects in the past: my Pong clock and my Enigma Machine simulator. To make physical realizations of these projects, I relied on some boards that I bought a few years ago from AtariAge, but when I checked a few months ago, it appeared that they had stopped selling […]

Animated Vector Graphics on an Oscilloscope

February 27, 2011 | My Projects | By: Mark VandeWettering

I lost the original edit to this post. Recreated. So, while watching the Oscars, I decided to hack together a simple little graphics program that would allow me to generate more sophisticated graphics for the oscilloscope. I ended up with 263 lines of code that implemented a simple matrix-based set of graphics commands. Eventually, I’ll […]

Using an oscilloscope as a graphics display device…

February 26, 2011 | My Projects | By: Mark VandeWettering

I’ve been meaning to do a project like this for quite some time. The basic idea is to write a program which can generate sounds which drive the oscilloscope in X/Y mode so that it will draw graphics on the screen. After an hours worth of tinkering: There is obviously some bugs, so I am […]

Arduino + MCP4725 Breakout Board

February 24, 2011 | Amateur Radio, Arduino, electronics, My Projects | By: Mark VandeWettering

Well, the other I2C based breakout board I got from Sparkfun was for a Microchip MCP4725 DAC. It’s a 12 bit device, and will eventually do duty controlling the voltage controlled oscillator in my beacon transmitter. For tonight though, I just wanted to make sure I could program it, so I soldered on some header […]

DS32kHz 32.768kHz Temperature-Compensated Crystal Oscillator

February 24, 2011 | Amateur Radio, Arduino, electronics | By: Mark VandeWettering

In considering the long term accuracy of the RTC chip that I was playing around with, I did some additional thinking and reading. My understanding is the error comes from the accuracy of the crystal oscillator: the 32.768Khz timing crystal probably has an accuracy of 20ppm or even larger. My guess is that this is […]

Arduino + DS1307 Real Time Clock

February 23, 2011 | Amateur Radio, Arduino, electronics | By: Mark VandeWettering

Okay, this is no big deal: lots of people have done it before. But while I was watching TV, I soldered some header pins to the DS1307 based real time clock board I got from , and coded up this simple program to read the time from it. I’d never really used the Wire […]

PCB Order via DorkbotPDX

February 23, 2011 | electronics | By: Mark VandeWettering

A while ago, I remember hearing that DorkbotPDX had some deal where you could submit PCB designs and have them ganged with other designs and manufactured for a pittance (or at least, a small number of pittances) but I hadn’t bothered to chase down the details. Recently, I’ve thought of making a small board with […]

Students to photograph Discovery flyby at 100,000 feet | TG Daily

February 22, 2011 | Amateur Satellite, Amateur Science, High Altitude Balloons | By: Mark VandeWettering

Interesting. A group of students are launching a high altitude balloon “some miles” from the launch site of the Shuttle Discovery at Cape Kennedy, and will be streaming the video of the event as recorded by a pair of Android phones on board. I suspect that any video so streamed will be less than stellar, […]

Dennis Klaat on Formant Synthesis

February 19, 2011 | Voice Synthesis | By: Mark VandeWettering

I’m in serious danger of digressing into trying to learn more about speech synthesis. The discovery of CSpeak, it’s relatively lack of intelligibility and inability to properly formulate consonants has me oddly intrigued though. I’ve been digging for more information, and the source code for rsynth yielded a link to: Dennis Klaat’s Software for a […]

Your first Digital to Analog Converter

February 17, 2011 | electronics | By: Mark VandeWettering

To control my simple Beacon, I used PWM and as simple (but slow) RC filter. That worked good enough for a test, but I really wanted the voltage changes to be more rapid. What alternatives are there? Well, I actually ordered a $5 I2C DAC board from Sparkfun, but it hasn’t arrived. The obvious low-tech […]

Battle of Speech Synthesizers: CSpeak vs. Festival

February 17, 2011 | Speech Synthesis | By: Mark VandeWettering

Okay, this kind of like watching “America’s Most One Sided Fist Fights”, but I was diddling around with Cspeak, which is a speech synthesizer that is just 150 lines of code long, and thought I’d try to see just what quality it was capable of. Well, it’s (not surprisingly) pretty hard to understand most of […]

CSpeak and Cantarino

February 17, 2011 | Link of the Day | By: Mark VandeWettering

Yesterday’s surfing churned a couple of interesting links on the subject of speech synthesis and computer singing. I wasn’t really explicitly looking for this stuff, and can’t reconstruct what led me here, but I thought I’d archive this here. The first is a link to a formant based speech synthesizer in just 150 lines of […]

Using PWM to Generate Analog Output

February 16, 2011 | electronics | By: Mark VandeWettering

Analog Devices Microchip has this nice little application note on using pulse width modulation. Seems like it will be useful if you wanted to (for instance) generate some simple sounds using the Arduino. AN538: Using PWM to Generate Analog Output.

The Ham’s Inconsistent Love/Hate relationship with Progress and Technology

February 16, 2011 | Amateur Radio, Rants and Raves | By: Mark VandeWettering

WARNING: pontificating and ranting ahead. You’ve been warned. Tom pointed out that I had an inadvertent markup error which ended up dropping several paragraphs of this post. It is now corrected. Julian, G4ILO followed up yesterday’s post about technology not being good for ham radio with a nearly equally confusing one today entitled Platform for […]