The personal website of Scott W Harden

Post-Defense Day 1

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 SkyCraft, 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 just a prototype. What does it do? It’s complicated. It’s basically just an exercise in microchip programming.

Future Scott reacts to this in August, 2019 (10 years later)

LOL! That's a pipette box! A chip socket was sunk into a plastic enclosure somehow! And that "regulated power supply" is an LM7805 on non-metallic perfboard screwed to two Jenga blocks!

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 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 14m!

This is a 5v regulated power supply I built. The headphone adapter is for easy connection to the serial port. It has a power switch and a program/run switch (allowing use of pin 13, serial out) while still “connected” to the PC.

I’ve slightly improved the connection between my radio’s coax cable to the J-pole antenna I made.

I’m able to get pretty good signals from this antenna, but it’s probably not likely to do much to my assembly skills (and lack of tuning), and more likely due to the fact that I have an unobstructed view of middle/southern Orlando from the 3rd story of my apartment balcony. I could probably wire up a rubber duck on a stick and get good results with that location! I’ll miss my reception when I move.

Mental Fragmentation

Summary: The writer is too busy to write a full blog post right now, so they are sharing small notes, images, and links that they have been saving over the last couple of weeks in the hopes that someone will find them significant and decipher their meaning.
This summary was generated in 76.32 seconds from an original post containing 752 words.

Thesis Countdown Continues

Summary: The author is struggling to remember where they were going and ends their rant by promising to return to their blog soon with a thesis to write.
This summary was generated in 48.15 seconds from an original post containing 1,182 words.

Transmitting Around the World

Summary: The author of the blog post is excited about QRSS and wants to try it out, but they have to finish their thesis first.
This summary was generated in 37.58 seconds from an original post containing 110 words.

Transmitting Around the World

One of my recent fascinations is QRSS, a super-low power mode of transmission over the airwaves. Picture this: get a ham radio setup which outputs dozens of watts of power, use a microcontroller to transmit data (frequency-shifting Morse code), use FFT on the receive end to view it on the computer, now increase the time between the “beeps” to tens of seconds and decrease the power to milliwatts and receive the signal thousands of miles away - that’s QRSS! How cool! I want to try this badly… but I have to get back to lab - I have a thesis to write!