One Year Anniversary

Yesterday was the official 1 year anniversary of To the Rails. I just want to say thanks to all of my regular readers, and I hope someone out there has taken something away from my ramblings in 2011.

My goal is to make this blog far more all-encompassing as I move into 2012. I think I can provide a new perspective on topics that I once thought had been done to the death. I read a lot online about areas of electronics that I care about and I have come to find that many articles lack a big picture focus or leave out critical details that allow consumers or the lay person to come to their own understanding. While I hope to never lose the hobby electronics spirit that created this blog, I do think there is more out there to look at then servo motors and LEDs (as cool as those things are).

As part of my 1 year celebration I want to look back. That is why I have gone back through all of my old entries to provide you with some stats. Some are based on Bloggers automated view count tracking system, while others are of my own creation. This blog was never created to generate large view counts, but I am impressed with how far it has come in only a year. Thanks again to everyone who has supported this blog and I look forward to a new year, new topics, and a new logo!

To the Rails Statistical Breakdown

Number of times I promised to do a blog explaining something: 15

Number of times I kept my promise: 5 (suckers)

Number of times Apple was mentioned with hate: 4

Number of Simpsons references: 5

Most Viewed Post: The 7-Segment Display (1,298 views)

Least Viewed Post: Happy Birthday, Tesla (5 views)

Highest Number of Views in 1 month: 908 (December 2011)

Blogger Stats

Just an Epic Tesla Comic

I found this online today and thought it was just too amazing not to post. Enjoy Mac fanboys.

New Header Designs

Okay, I have put this off long enough. Today is the day I debut my ideas for the future look of To the Rails. Below I have laid out five separate headers that I have designed in the last month or so, all of which are styled differently from the rest -- though admittedly there is a liberal use of lightening and circuit boards throughout. Let me be the first to say, I am not an artist and all of these are pretty uncomplicated designs with little to no artistic flair. Still, I would like to spruce things up around here and I think one of these designs would do the trick.

First, a couple of quick notes on my efforts: 

• All of these headers were designed in GIMP, which I recommend to anyone looking for a somewhat powerful, free image editing software.

• I am well aware that 00 (yes, binary for the extra geek factor) and 11 look very similar. I couldn’t decide which one I liked more so I put up both.
• I am open to creating something new from elements of these first attempts. Let me know in the comments which parts you like among the five (color, font, etc.)  and maybe I will combine them into something new for the blog. Also let me know if I need to scrap the lot and start over (I don't have feelings and this isn't my area)
• The color scheme for 10 is different than the rest because I designed it when I was first learning the software and was just playing around. I liked it enough to keep it in the bunch for this trial run.
• Lastly, if you think these are bad you should’ve seen the rejects. I will search my trash can to see if I can find them for a parody post after we pick a new header.

Make sure to vote in the poll I have created in the upper right (above the entry history). I figure any anonymous readers out there might be more likely to contribute to the voting this way as opposed to leaving comments. I look forward to hearing what you all think.

HEADER 00.

HEADER 01.

HEADER 10.

HEADER 11. 

HEADER 100.

Polls close on January 30th at 11:59pm so get those votes in soon!

Voltage Divider Quiz Solution

I was lucky enough to get a few responses on my quiz question this time around. While there were many failed attempts at finding the answer among my friends, someone did come through and restore my faith in humanity. Let’s look at how he did it -- or at least how I assume it was done.

Step 1: Since I told you in the hints that this was a comparator circuit, you should remember that a comparator compares two input voltages and outputs a high or low signal if one is above the other, which can be controlled via the circuit configuration. Since this opamp has a relatively high input impedance, you can ignore any loading effects and solve the two voltage dividers very easily.

Step 2: Find the reference voltage going into the inverting input (-) of the comparator using the voltage divider equation. At this point you are only concerned with the bold portion of the circuit in the picture above so the equation should look like:

The units cancel on the ohms range and your answer ends up in volts. You now know that the LED will turn on when the input voltage on the non-inverting input (+) goes above 3 volts.

Step 3: Apply the voltage divider equation again to the 4.7kΩ  and ??? Ω resistor network in bold in the picture above. This time you must rearrange the terms to solve for the mystery resistance using a known voltage. The equation should now look like:

 

This equation requires a few more steps to solve, but it is not complicated if you know basic algebra. Dividing both sides by 5 volts you end up with:

 

Now get rid of the denominator by multiplying both sides by its value (4.7kΩ + ???Ω) and end up with:

Therefore, the LED should turn on when the mystery resistance is above 7.05kΩ because it will cause the output of the comparator to go high.

Step 4: Here on To the Rails we care about numbers as much as the end result so I decided to build this circuit and do some comparisons between our predicted outcome and the practical implementation. I used a variable resistor known as a potentiometer (the blue thing) to vary the resistance around the point that turns on the LED. Without knowing the resistance, I turned the pot to a point where the LED barely turns on in order to get the most accurate resistance reading possible. Once I felt I was as close as I could get to the resistance that causes the LED to turn on, I removed the pot from the circuit and measured its value. **NOTE** It is very important to remove the pot to measure the value. Leaving it in will cause you to measure the resistance seen by the pot within the circuit itself. And as always, NEVER MEASURE THE RESISTANCE OF A LIVE CIRCUIT!!

As you can see from the pictures, even with all the uncertainties associated with the manufacturing of the resistors, the accuracy of the potentiometer, and the voltage of the power supply, we still managed to get a reading of 7.09kΩ as our observed answer. For those keeping score at home, that makes our percent error only 0.57%...not bad.

To the Rails in 2012

The new year has brought some big changes for me in only a few short weeks and my blog production has trailed off a bit. Since I don’t have anything concrete to offer you in this post, I thought I would share some ideas I had for the future of this blog in 2012 as well as some projects I am currently working on that should find their way onto these pages very soon. I started this blog in early 2011 and with a year of experience under my belt I definitely want to make some upgrades to my presentation.

Back in the News

Some readers may have noticed that my Empires of Light entries have disappeared in recent months. These are entries where I look at four stories from the world of electric power/electronics from the previous month and classify them as important, frivolous, noble, or idiotic. Look back at the entry where I dreamed up this concept to see why.

I have been distracted with the holidays and working more on my own projects recently so those entries sort of fell by the wayside. While I like the idea of having a regular segment on this blog, I am not sure how much longer this one will stick around. I am still experimenting with formats, and I don’t want to make too many regular segments because it would leave little room for the entries about my projects, EE fundamentals, circuit concepts, and whatever the hell else I feel like writing about.

One of my newer ideas for a regular segment is to start posting EE trivia every week. My thought right now is just to post a few sentences of trivia related to something in electrical engineering, electronics, and/or technology each week.

Happy Birthday to Me

As part of the one year anniversary (Jan 30) here on To the Rails, I am currently working on a few new header designs for the blog. Homer has served me well these past 11 ½  months, but I feel it’s time to move on to something more dramatically stated rather than continue with a banner I threw together in paint one night. Originally, I wasn’t going to change anything else about the blog, but now I am considering changing the background and the circuit picture above my entry history. Either way, my plan for the header remains the same: the readers get to choose. About a week from now, I am going to post 4-5 headers I have designed in the past month for you to vote on. The one with the most votes will become the new logo banner for To the Rails. Get excited people.

DIY ‘til the World Ends

What does 2012 have in store for me personally when it comes to my DIY electronics projects? Well, when I first started this blog I came up with a number of projects that I wanted to complete and document for everyone to see. Since that time I have only made it through roughly 1/10^th of the list and I am adding more and more each day it seems. Right now I have 4 circuits I am working on as well as trying to build a couple of custom frames for my dual monitors and mocking up sample circuits every now and then for demos. I want to show my work on all of these over the next few months with time permitting. ***SPOILER ALERT*** I am getting into building my own test equipment so expect to see the results of my labors in that area very soon.

Making My Way in the World Today

I don’t talk much about my job on this blog because, frankly, my personal contributions are not all that interesting. Secondly, what I am allowed to divulge is extremely limited because I am frequently exposed to proprietary design information that various electronics companies don’t want getting out. I can tell you that I contribute to establishing energy efficiency standards for consumer products in the United States via the Department of Energy and the EPA’s ENERGY STAR program. Going forward I want to look more into energy consumption in the US through a series of experiments as well as explain how the energy standards process works for consumer products (i.e. TVs, set-top boxes, game consoles, external power supplies, etc.). This blog has mostly been about circuit level design up until now, but I am interested in expanding the scope to include some analysis of product energy consumption. The entire reason I became an electrical engineer was to try and help reduce our global demand for coal-fired energy by improving efficiency and finding alternative resources to fill in the gaps. While I have touched on these topics somewhat in the past, I really want to explore these areas more down the road.