Technical Drawings

When I was pretty young, my dad was working at a start-up with relatively few employees; maybe twenty or so. I used to go in and help with odd jobs. It started with assembling workbenches, pulling CAT5 cable and graduated on to mechanical assembly and packaging of products. Along the way I learned other skills too, like soldering, debugging, and illustration.

I grew up with exposure to Adobe Photoshop and Illustrator. Because of this exposure, I was asked to create an assembly drawing of our product. I had never done anything that complex before. I was sat down in an office with a computer running Adobe Illustrator, along with the assembly that needed to be drawn. I was pretty familiar with the part since I had assembled hundreds of them before. I worked for a full day (maybe more, I don’t remember since it was so long ago) and I created my first technical drawing.

Assembly Diagram for Indigita AVHD

I found that I enjoyed working in this style. Even today, I’m pretty pleased with how my first foray turned out.

Over the years I’ve had a few occasions to do this type of work, but not as often as I might prefer. When my family was involved with the Darpa Grand Challenge, I made some illustrations of the car, Golem 3.

Side view of a Prius

During my education I had numerous times when I was able to make use of this type of drawing for research papers and reports. In my internship, I created assembly instructions for mechanical arrowheads which relied heavily on technical drawings.

Assortment of product diagrams used in assembly instructions

Presently my full-time job description does not include this type of work, but I have found occasions when it became necessary to create drawings. For example, the user manual for the software I am working on needed diagrams to illustrate connection of the hardware with which our software operates. I took it upon myself to provide the artwork. It was a nice break from the routine.

User’s Manual Connection Diagram

In diagrams, it’s important to use visual cues to convey orientation and differentiate parts. It’s equally as important to reduce extraneous features in order remove visual noise and not distract the viewer. Finding that balance of conveying enough, but not too much, visual information is very rewarding.

I also like the freedom of working with fewer colors. In many instances, these types of drawing will be printed in black and white, and even when drawings can be viewed in color, it’s best to leave them less saturated as to not distract and draw the eye of the viewer to unimportant details.

Doing this type of work is very relaxing for me.

Microbolometer

My uncle is a physicist, and did some pioneering work in the field of thermal camera photo-receptors. He even wrote a book about the field in the 90’s, Fundamentals of Infrared and Visible Detector Operation and Testing (1990, James David Vincent).

512JMVWtmkL._SX331_BO1,204,203,200_

The publisher wanted an updated manuscript for a second edition of the book. He’s been working on that for the past couple of years, but ran into a problem. He needed a diagram of a microbolometer.

A microbolometer is a small sensor that is sensitive to infrared radiation. The radiation hits a sensitive material that then heats up, and its resistive value changes. By measuring the resistive change, a temperature can be determined. Thermal cameras, such as FLIR cameras, use an array of microbolometers to generate a thermal image.

Although diagrams exist, the most well known (and oft plagiarized) is in fact under copyright, and not available to be republished without authorization.

He asked me to create a new diagram that would convey the same information but be visually distinguishable from the other well-known image.

After some back and forth, this is the image we came up with. It had to be black and white for printing, and easily readable. He also wanted extraneous information removed, so that there were fewer parts of the image to focus on.

Microbolometer_3

For example, the thicknesses and dimensions, though accurate, are not labeled. To facilitate not having a labeled dimension between the ROIC and the temperature sensitive resistive element, there is a visible shadow. The image was created in Illustrator, and sent to the publisher as an EPS file.

The book, Fundamentals of Infrared and Visible Detector Operation and Testing second Edition (2015, John David Vincent, Steve Hodges, John Vampola, Mark Stegall, Greg Pierce), has been published, and you can see my diagram on page 94, Figure 3.3.

 

 

 

Apple Pi

IMG_2771_e

I recently (2 years ago) purchased a Raspberry Pi (The original model). I bought it off a friend who never ended up using it for anything useful. My intent was to run a small web server with it, and enjoy some savings over the old computer I use for a server that was eating up more than 100 watts of energy.

I also didn’t care for the case it came with. I also happened to have a first generation Airport Extreme that I also got second hand. It served it’s purpose, but had since died. I thought these two might be a match-made in heaven.

I gutted the poor airport extreme and inspected it.

It didn’t know what hit him.

I was going to throw out the PCB entirely, until I noticed that the Raspberry Pi had two holes that matched up perfectly with two holes on the Airport’s main board. I decided to keep the circuit board for mounting purposes, and reuse it’s input jacks since they line up so nicely with the enclosure.

I desoldered all the parts I could near the connectors, and then marked off the part of the PCB I could remove. The intent was to remove all the circuitry that would be difficult to desolder. The result was a completely bare, partial PCB to work with.

I then soldered power, USB and ethernet cables to the circuit board that would then connect to the Pi (so it’s not hardwired in, and can be swapped).

IMG_0231_e

Now I have a low power web server in a cute, unassuming box.

I also wanted to have the filesystem accessible over AFP so I could access it on my desktop. this was easily achieved by installing netatalk using the command:

sudo apt-get install netatalk

Now that I have the server’s disk mounted on my Mac’s desktop, naturally I need a representative icon.

Airport2

Using a reference picture, I was able to throw this icon together in Illustrator in about a half-hour’s time.

© 2007-2015 Michael Caldwell