vilimpoc.org

During the fall of 2019, I spent some time seeing which grocery store plants I could get to grow at home. You know what I mean, the potato that had sprouted too many eyes, a ginger plant that seemed to be pushing its way out, green onions, and lemongrass stalks.

These plants had survived through sheer tenacity, so I figured I'd give them a longer lease on life.

This is writeup of the process of modeling and printing a support structure for a bundle of green onions in a standard food-safe plastic bucket. Though it didn't work out as I'd hoped, it was still a fun experiment.

When you have a hammer, everything looks like a nail: When you have a 3D printer, everything looks like it should be 3D printed.

In this case, I modeled a holder to reuse the stainless filter basket from an IKEA teapot to use it with a regular mug. The first two versions weren't great, so I made a third. Clearly I have too much time on my hands.

Take 1 part electric screwdriver + 1 part cheap IKEA spice grinder + 1 part 3D printer and create an electric spice shredder that can quickly pulverize a load of spices for that next curry you want to make.

Anyone with a 3D printer can print up the pieces needed to build this, the only extra piece needed is a 50mm adjustable pipe clamp.

Sets up a high-water usage canary for the Interrupt Service Routine, main thread, and other thread stacks; as well as for the heap memory. Goes pretty deep into the undocumented operating-system interfaces.

I wrote this to debug memory issues I encountered, before newer versions of mbed OS made this type of functionality part of the mainline.

Life is short. Experience this fact vis(cer|u)ally.

Not all USB Serial Adapters are equal.

After running into errors when programming an embedded microcontroller, it took me a bunch of time to determine that the issue was in the serial adapter chip hardware.

This was a comparison of the most widespread chips from FTDI, Prolific, Silicon Labs, and WinChipHead, which took a couple of weeks to complete.

A bit of App Script for Google Docs that lets you forward geocode (address -> lat, long) and reverse geocode (lat, long -> address). Took a bit of experimentation to get working, but learned how to programmatically modify a Google Sheet. Loads of fun.

Click here to try a live copy of the script in a Test Spreadsheet.

You must be logged into Google for the script to work due to the way the Geocoding Maps API quotas work. It won't work for non-logged in or Incognito Mode users.

A command-line interface for Arduino with simple commands to control the GPIOs, read / write EEPROM, and read the ADC pins.

This was one of the hackathons I took part in in 2015, in which I built a fun little temperature-based pump controller using the now-obsolete Intel Edison.

A map of places to eat in Berlin.

I'd been working on this for a while, and haven't updated it in a while.

Google Maps has a lot more sophisticated tagging and editing of personal maps now, but when I first created this map, they didn't.

A map of spectrum utilization from 54-806MHz.

Something I threw together to see how well our precious television spectrum is being used.

Project page for the embedded Linux work I was doing on the LogicPD SH7727 (Renesas SH3) development board.

Calder-A

Calder-A is a bigger brother to Hellbender. Another "caseless" computer, this one in the style of Alexander Calder's mobiles, in other words, mobile computing. Reengineered into Extrovert, below.

Extrovert Caseless

After deciding that Calder-A was just too unwieldy for normal use, and ultimately a bit ridiculous, I reworked the raw materials into a more compact and usable system. I call it Extrovert, because its guts are all on the outside.

I created a new Win32 / Windows installer for the MySQL database software using Nullsoft's Install System. Copies of the server and the scripts used to generate the install files are posted here. Have a nice install!

[mv 12:40 PM 3/27/2009: This stuff is ancient, and I've removed the binaries, but left the notes on what I did for my own sake.]

This script takes an input directory and recursively replicates it with zero-length directory and file entries to a specified output directory.

What this was used for:

Rather than running the compress/decompress cycle on real data while building-testing an installer, it is much easier if all the input files are simply zeroed out, making compression instantaneous.

Warbiking

While I was in Washington, DC, I had the opportunity to do a little Warbiking. The density of Wi-Fi in Washington is excellent.

PortMonitor/G: A graphical network port watcher.

This is a program I wrote to familiarize myself with the winpcap packet capture library, thread programming concepts, and the SDL multimedia library.

I bought a new used laptop recently (12.19.2002) and the battery that came with it was Dead On Arrival (DOA). Luckily, I had an extra battery pack sitting around from my old laptop, and I correctly predicted that the actual lithium cells would be identical. So I ended up just swapping the dead cells for live ones. Here is the surgery in pictures.

Just a couple of screenshots from an infared file transfer between my two laptops, in case anyone wants to know just what they look like. Nothing really special.

Euphemistic Safeway Map

Washington, DC has numerous Safeway grocery stores that residents have lovingly nicknamed such things as: Social Safeway, Soviet Safeway, Sixties Safeway, and so on. Just for kicks, I decided to plot them out on a map.

FCC ITFS Antenna Map

Lately, I've been working on the visualization of geographic coordinate data from FCC license databases. Unfortunately, professional GIS packages cost on the order of $1,000+ and I don't have that kind of money. So I wrote my own package.

The heavy lifting is done using PHP and the GD graphics library extension, with data sourced from a MySQL database stored on my laptop.

Way Out West GPS Data

When I originally wrote the GIS analysis package, I ended up with a fairly flexible framework which I tweaked to process more diverse datasets, such as the GPS data I gathered on my trip out West last summer.

Radio Spectrum Measurements

Results from electromagnetic / radio spectrum measurements taken June 10, 2003 in cooperation with the New America Foundation and the Shared Spectrum Company.

A Collaborative Effort of The New America Foundation and The Shared Spectrum Company, this is a short memo describing measurements of the electromagnetic spectrum between 30MHz and 3GHz. What we found out was that ~62% of the radio spectrum is unutilized during peak hours in the urban area around NAF's headquarters. [2003-07-16]

Also included is a snippet of video from the presentation we made at the New America Foundation on June 20, 2003.

A short (4pg) Issue Brief I put together with J. H. Snider, a Senior Research Fellow with the Spectrum Policy Program at the New America Foundation. In it, we discuss the potential for a transition of the broadcast television spectrum towards greater unlicensed use. [2003-07-16]

My first published article, appearing in the August/September 2003 issue of IEEE Potentials magazine. In it, I discuss the importance of public policy and why engineers need to participate in the political decisionmaking process.

Argus

Created as part of our senior capstone curriculum at Ohio State, the Argus Project represented the packaging of many distinct skills into a compact, computer-operated, remote-controlled truck.

Ultimately, our team fit two wireless transmitters, two microcontrollers, and a host of sensors into every available space on the truck.

Available sensor data included: acceleration, GPS coordinates, velocity, and motor/battery temperature.

Additionally, our system had ability to control lights on the truck including: headlights, brake lights, reversing lights, turn signals, and fog lights.

Created by Craig Bennetts, Shefali Patel, and I for a course in medical imaging. This presentation details the process by which High Intensity Focused Ultrasound energy can be used to treat prostate cancer and other tissue by inducing ablation and localised necrosis of cancer tissue.

Here is a presentation I created for the Washington Internship for Students of Engineering (WISE) as part of my summer 2002 research project. I discuss a few of the problems currently faced under the current system of copyright.

Appended is a copy of the final report I wrote for the WISE program. (It was once mirrored at the WISE program website.)

There were numerous comments in this docket that supported or dissented the use of GPS + database-backed interference mitigation for unlicensed devices (a user-side solution). A better idea would be to shift some responsibility for interference mitigation onto licensed television broadcasters (a server-side solution).

Two methods should be considered: (1) adding a geolocation signal to NTSC analog television broadcasts, by tucking data into the Vertical Blanking Interval (VBI), and (2) adding a geolocation signal to an ATSC digital television broadcast, by tucking location data into the Field Synchronization Segment.

Adding a geolocation signal that uniquely identifies television towers is a good idea that mandates an appropriate level of spectrum management and stewardship on licensed broadcasters, as already is expected of end users. The proposal also offers a great public service, making for a geolocation system similar to GPS, with potentially more robust results for urban users.

Hellbender Archive

The Hellbender Archive is a small "caseless" computer I built using 12" threaded steel rebar and custom cut wood supports. It's getting up there in age, but it runs Linux + Apache + PHP and SSH pretty handily and it also handles the video capture for my webcam. While I was travelling in Mexico, I remitted close to a gigabyte worth of photographs to it over the course of three months. Its security has never been compromised.