Fran's Writings on Design and Engineering
Page 4

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List of articles on page 4:
(November 2012 - January 2013)
SMD LED Test Board
The 1984 Heathkit Catalog
X-ray Analysis of the Apollo Saturn V LVDC Circuit Board
Building a Dedicated Bootloader Board for New ATmega328P Microcontrollers
The Apollo Saturn V Launch Vehicle Digital Computer (LVDC) Circuit Board
Ask Fran: Build Your Own Friction Welder!
Do It Yourself Digital Fireflies
Fran's Dangerous Toys: The Jacob's Ladder
Ask Fran: AM Radio
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SMD LED Test Board
(Jan. 2013)
One of the things that you always end up doing for a new project is making small test breadboards of the various parts of the system.  I have posted some prototypes of various test stages of other projects here on my pages and here is yet another - This is a little board I built to test the relative brightness of several different types of surface mount LEDs that I got for a new project, and also an application of a small SMD voltage regulator.  Not pretty, but these kinds of thrown together breadboards are the necessary proving grounds for whittling out the bugs and unknowns in more complex designs.

Fran's Geek Heaven:
Highlights of the 1984 Heathkit Catalog

X-ray Analysis of the Apollo Saturn V LVDC Circuit Board 
(January 2013)

 My preliminary analysis of the Saturn LVDC board:

- The X-ray image is negative, so white elements are completely blocking the X-rays while black parts show no obstruction.  Most of the board is grey due to the continuous ground plane and overlapping traces, and white spots mostly indicate lead solder.

- Each logic device package contains 4 semiconductors.  The ceramic wafer bases of each logic package have conductive traces deposited on both the top and bottom sides, and the semiconductors (called Flat Chips) are surface mounted with solder balls by reflowing to these traces face down on the top side of the wafer (it has been noted that the later IBM 360 logic devices were made in this manner- see link below).  The small white square shapes you see arranged in threes are the solder pads connecting each semiconductor to the traces. 

- The board has a continuous ground plane layer, and the only openings are around the vias, which you can see as a black ring around all of the via pads that show a clearing through all layers.

- The 35 mounting positions on the board for the logic packages appear to be identical, which again would suggest that these circuit boards were designed to be universal.

- The logic packages do not appear to contain capacitors.

- This board has a lot of layers!

- The bone in my thumb is apparently not broken.  :)

Xrays provided by the Daniel P. Thomas, DMD

Click on the images below for full size:

Building a Dedicated Bootloader Board 
for New ATmega328P Microcontrollers
(December 2012)

The very first thing that I tried to do when I began my Digital Firefly Jar project was to burn bootloaders to newly manufactured ATmega328P microcontrollers.  I knew that to reproduce my project I would need to make multiple programmed ATmega328's and in anticipation of doing many Arduino projects I bought the chips in bulk.  I knew that I would have to burn bootloaders to all of them in order to upload and use my sketches.  I bought a used Arduino Duemilanove to do this, and there was a clearly laid out tutorial about burning bootloaders on a breadboard on the Arduino site.   It seemed like a no brainer - an easy task - but it wasn't...  It just did not work!  Many attempts using the set up in the Arduino tutorial met with no success, so I went to the blogs and saw that many people were having problems doing this, and there were as many apparent solutions as there were issues.  I tried every configuration from every blog I could find on the topic: adding pull up resistors, changing power supply, altering settings, changing cables, etc....  but nothing worked.   The afternoon I spent trying every one of these configurations to burn a bootloader met with nothing but errors.

So I decided to go a different route and tried the dedicated bootloader board project suggested by Ladyada that used a very nifty Arduino sketch that had the Duemilanove's ATmega328 do the task, and this elegant set up works flawlessly.  Success!  And a really cool project too!

The Apollo Saturn V Launch Vehicle Digital Computer (LVDC) Circuit Board 
(Dec. 2010 - updated Dec. 2012 -updated Jan. 2013)

This is a picture of the Apollo Saturn V LVDC board that is in my collection.  It was a spare that would have been placed into one of the later Apollo moon rockets.  It is a marvel of its time and demonstrates so many firsts that it stands as a representation of the tremendous leaps that technology took for the Apollo program.  It is the first example of applied microchip technology [update- individual transistors wired into gates on one ceramic chip], surface mount components, multi-plane circuit board construction [update- 12 layers with full ground plane], plated through-hole vias, and modular logic in one system.  The relationship between this LVDC IU board and all modern computers is staggeringly close by electronics technology perspectives, and it is a monumental leap past anything that had ever existed before it.  Digital watches, pocket calculators, home computers, and all facets of modern electronics sprung out of these technologies, developed solely for the purpose of flying this unheard of machine, the fantastic Saturn V Moon Rocket. 

The custom made integrated circuit chips were apparently made in two types (need to confirm this), to contain either two NAND/AND gates or inverters each [update- the LVDC may have contained several types of logic devices but my board contains only two types of logic devices, NAND and NOT (inverter)], with up to 35 IC's per board, and banks of these individual hard wired logic boards made up the heart of the LVDC.  I had read long ago that it was thought that NAND logic was chosen because it was inherently more stable to produce, but my latest findings were that the gate choices were limited by the component count per divice. Reliability was a very big consideration in the design of the IU.  The IU also ran on core memory, again chosen for its proven reliability.

The LVDC was manufactured under contract by IBM and was housed in a ring at the top of the Saturn V rocket, behind the CSM.  The Saturn V was controlled and monitored on the pad by ground operators via an umbilical, but once the ignition sequence start was initiated the IU took over.  From that point to orbit all guidance, attitude, control, engine adjustment, telemetry, staging, and all other onboard operations were controlled entirely by the IU.  Because of the LVDC and IU the mighty Saturn V was the most sophisticated fully autonomous system then constructed.  The core memory program it ran on could not be programmed on the fly, it had to be set on the ground, so the flight path was predetermined.  As such the IU was also responsible for any course correction and compensating for any malfunction, as it did on Apollo 13 when a center engine failed. During ascent the only human control was the option to abort, and until the final staging when the CSM was free in orbit it was the IU that called all the shots.

When I look at this magnificent artifact of our Apollo program I am always awestruck.  It recalls an excerpt from one of my favorite poems, Ode, written by Arthur O'Shaughnessy in 1874

WE are the music-makers, 
And we are the dreamers of dreams,
Wandering by lone sea-breakers, 
And sitting by desolate streams; 
World-losers and world-forsakers, 
On whom the pale moon gleams: 
Yet we are the movers and shakers 
Of the world for ever, it seems.

Ask Fran: Build Your Own Friction Welder!
(December 2012)
Citizen!  New opportunities await you in the exciting field of Friction Welding..... At Home!  Yes - you too can enjoy the countless wonders of permanently attaching some plastic things to other plastic things - at will.  In this video you will learn how to make your own friction welder, and I demonstrate just how amazingly strong a spin-weld is.  Have fun, be safe, and enjoy!

Do It Yourself Digital Fireflies
A fun project coded in Arduino for the ATmega328 Microcontroller
(December 2012)
This was a simple little project that was really just an excuse for me to learn Arduino.  I bought some really attractive Ball canning jars at the market and thought that it would be really cool to use them to make some kind of bedside firefly jar.  I thought that I would use an array of RC transistor timers to drive some vintage 70's amber lens LEDs I had in stock.  But I wanted these virtual fireflies to act like the real thing, and I soon realized that there would have to be 4 separate operations to depict a realistic firefly blink, with a quick fade-on period, a brief stay-on period, a slower fade-off period, and a long off-rest period.  Visualizing the large array of discrete RC timers I would need to create several fireflies was going to be prohibitively complex to shove into a jar lid, so I thought that this would be a really good job for a microcontroller.  Read more....

Fran's Dangerous Toys: The Jacob's Ladder
(Nov. 2012)
In this vlog I show a little prop I made some 20 years ago that packs a mighty whollop.... of fun! I explain some of the principles involved, just in case you're curious - or you can just watch me burn things with 10,000 volts of electricity. Enjoy!

Ask Fran: AM Radio
(Nov. 2012)
This is a short vlog about the joy of long distance radio listening and a little explanation about what makes it possible.  It is 4:15 so you can skip the science and just turn on an AM radio and enjoy.

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