Monday, September 17, 2012

Unique Excel Uses: Designing Roller Coasters

We’re always looking for new and unique uses for Excel and I recently stumbled upon a very thrilling example of what Microsoft Excel is used for. Travis Rothbloom is a mechanical engineer and aspiring roller coaster designer. He decided to design a roller coaster for a school project using a  combination of Excel and MatLAB. This massive spreadsheet with roller coaster physics formulas contains 8500 rows by 50 columns of data! Travis explains how he compiled his engineering spreadsheet:

The first thing that I established in my spreadsheet were the constant values that I used, namely gravitational acceleration, friction coefficients, and finite step size along with other parameters that helped define the physical geometry of the track. Excel's functionality of maintaining a reference's cell index with the "$" symbol really came in useful when I needed to change friction values - all I had to do was change the one cell storing the coefficient and the entire spreadsheet (thousands of lines of data) would update automatically.

roller coaster physics formulas
Formatting, constant values, a table containing statistics, and an embedded equation using Excel's native trig functions.


Then it was time to take the physics equations that I derived and embed them into the spreadsheet. This was pretty easy given that Excel has built-in methods for calculating trigonometric functions, powers/roots, and division remainders while maintaining the proper order of operations. Given that many of the calculated rows' values are dependent on their respective column's previous value, I had to set up a row to store initial conditions as to not cause a null reference. When I did have null references or circular dependencies, however, it was easy to spot the source with Excel's error handling mechanisms. Formulas that described the dictating curves of the track, whether they be in g-forces, roll angle, curvature radii, etc., relied on an incrementing time index whose interval was dictated by the finite step size parameter's cell.

With all this, I relied on Excel's formatting to help visualize what was transpiring in my spreadsheet. I highlighted both rows and individual cells to indicate what was a dictating, inputted value vs. what was being calculated by other values; this was not the same for every row because I would sometimes rearrange the equations for nuanced track elements, and using this color coded system made this a whole lot easier to keep track of. I also used blank columns highlighted with a color to separate columns into groups for easier viewing. Along with that, I frequently would hide multiple columns or rows to help navigate the spreadsheet as thousands of lines and up to 50+ columns of data can become unwieldy at times. Lastly, I created a table at the top of the sheet that maintained the maximum or minimum values of particular values such as speed and different g-forces.

unique excel uses
2D plot showing an elevation of the ride


Although Excel doesn't have a built-in 3D plotter, I created 2D plots of the track coordinates so I could view the track geometry within the spreadsheet. I stored these in separate tabs for easy navigation. Also stored in a separate tab was any other miscellaneous information that I would reference.

Finally, I made use of the fact that other programs usually have an easy time reading/parsing Excel documents. I frequently imported my spreadsheet into Matlab for further post-processing, including 3D plotting and some other calculations. It's not necessarily the case that Excel wasn't able to do any of these other things (for example, I have found user-created 3D plotting macros online) but rather I'm more comfortable coding in Matlab rather than VBA. People would often ask me why I didn't just work in Matlab for the entire project, to which my response was that I thought (and still do think) that working with mass data sets in spreadsheet format is best done by Excel and since it is found on so many computers and it's so easily read by other programs, it was easy to work on the project wherever I was.

matlab roller coaster
2D plot showing the ride's plan

Thanks again to Travis for sharing his awesome “Excel uses” example and good luck towards your goal of becoming a coaster creator - and let us know when you do so we can go ride your  breathtaking creation! Read more details about Project Soar at his website.

Subscribe to our newsletter for more updates and drop us a line (or a comment) if you know of someone with a unique or interesting  “Excel Used For” example.

Sunday, September 9, 2012

Mileage Reimbursement Form Template

Today I am going to share with you an Excel spreadsheet template I use every week, my mileage reimbursement form. Many companies today use mileage forms to help log and keep track of employee’s mileage when they travel. This template allows you to input your mileage as your total number of miles driven or you can enter your beginning and ending  odometer readings thus giving you your total reimbursable mileage. If you’re setting this up for your own business you can also choose different payback rates depending on if the vehicle driven is personal or company owned.

keep track of your miles form

My mileage sheet is very simple and easy to use. All grey colored cells are formulas. You shouldn’t need to change any of these and can use it as is. The mileage form assumes the report date is on Friday. The formulas then use this date to input the dates for the rest of the week using simple subtraction. I also use the ROUND function in order to round the amount owed to the employee to a nice number (like 9.85 instead of 9.84586).

Below is a link to a free download of my Mileage Reimbursement Form spreadsheet. Please feel free to let me know if you have any questions. Check out our Downloads page for more free Excel spreadsheets or the project management page for other templates and resources.


What about you? Do you have your own mileage log spreadsheet? Does your company track employee's mileage?

Nick
Effective Mileage Tracker

Tuesday, August 21, 2012

Gantt Chart Template Pro Giveaway Contest

Gantt Charts are extremely useful tools for planning and  project management. These bar type charts are helpful when laying out schedules and tasks associated with a given project. A spreadsheet version of a Gantt chart is often a cost effective alternative over more expensive project management software (like Microsoft Project).

In my experience, one of the best Excel Gantt charts I’ve used is the Gantt Chart Template Pro from Vertex42. This easy to use tool will make your project planning more efficient. Helpful instructions and an FAQ section are included within the spreadsheet.

You can test drive the free version of the Gantt Chart but you will need the Pro version to unlock all of the features, such as grouping rows. Fortunately, I have a copy of the Pro version to giveaway for free - a $39.95 value! 
vertex42 free spreadsheet download

Entry into the giveaway contest is simple:

  1. Visit Vertex42’s website.
  2. Leave a public comment with your name on this blog post about how the Gantt Chart Template Pro will help you manage your project and what you will do with it.

That’s it! But wait. You want even more chances to win? Increase your chances of winning by doing any or all of the following:
  1. Subscribe to our free email newsletter to hear about future contests
  2. Share this post via Twitter, Facebook, LinkedIn, etc. Be sure to include in your comment how you shared the post so I can credit you for the additional entries.

The contest period starts today and ends Wednesday, September 12th. I will use Excel to randomly selected a winner. Enter now for your chance to win the free Gantt chart Excel template and improve your project planning.  Thanks and good luck!

-Nick
Efficiently Planning Projects

Thursday, August 16, 2012

Friday Fun: Thanks for sending the Spreadsheet

I've decided to start a new, lighthearted series called Friday Fun where I will attempt to post a funny Excel related joke, story, or image. Today I've found an all too true eCard from someecards.com. Enjoy!

funny excel spreadsheet joke

Sunday, August 12, 2012

Excel Create Folder Macro Updated

Today I’m going to revisit how to create a folder in Excel. There’s been some good discussion on my earlier post about to use an Excelmacro to automatically create folders. My original version only created folders in the same file where the Excel spreadsheet was saved. After some reader questions and collaboration we’ve created a new version which allows you to browse to the directory location where you would like the VBA macro to automatically create all the folders you have listed and selected in the Excel workbook.

A reminder of how the Excel macro creates folders. Make your list of folders in any column in a worksheet (which does NOT have to be saved like in previous versions). Select the range of names you want to create. Run the macro.

To open a folder browser with an Excel macro we need to create a shell application object using this code:  

Set ShellApp = CreateObject("Shell.Application").BrowseForFolder(0, "Please Choose The Folder For This Project", 0, OpenAt)

I put together a short video showcasing the end result and how the Excel VBA create folder macro should work. Also, if you’re looking to build your own website watch the video to get a 25% off coupon for Host Gator.


The complete code is listed below. Now you can show your bosses and coworkers how to make a folder with Excel. Please join our newsletter for more Excel tips.


Sub Create_Folders()

penAt = "My computer:\"

Set ShellApp = CreateObject("Shell.Application").BrowseForFolder(0, "Please Choose The Folder For This Project", 0, OpenAt)

'Set the folder to that selected. (On error in case cancelled)
On Error Resume Next
BrowseForFolder = ShellApp.Self.Path

'create the folders where-ever the workbook is saved
Dim Rng As Range
Dim maxRows, maxCols, r, c As Integer
Set Rng = Selection
maxRows = Rng.Rows.Count
maxCols = Rng.Columns.Count

For c = 1 To maxCols
r = 1
Do While r <= maxRows
If Len(Dir(ActiveWorkbook.Path & "\" & Rng(r, c), vbDirectory)) = 0 Then
MkDir (BrowseForFolder & "\" & Rng(r, c))

On Error Resume Next
End If
r = r + 1
Loop

Next c
End Sub
 

Create Folders.xlsm Download


Monday, August 6, 2012

Weighted Olympic Medal Count 2012


In honor of the 2012 Summer Olympic Games currently being held in London, England, I decided to create a Microsoft Excel spreadsheet template for the medal count. There are two primary methods most websites appear to be ranking the 2012 medal count. Sites like Yahoo rank countries by the total number of Olympic medals won. Other sites, like the International Olympic Committee (or IOC) rank countries by their gold medal count. (And others, like this one from Forbes, rank by other factors like per capita or GDP.)

If you rank by gold medals countries like Great Britain and South Korea look really good. On the other hand, Japan has 27 medals, ranking fifth overall, but only TWO of them are gold. I’ve devised my own ranking system to give each Olympic medal a weight where the silver is worth half a gold medal and a bronze is worth only a quarter of the gold. Based on this new scoring system, the Olympic results suddenly become quite interesting.

 

I looked at the Olympic Game results for the top twenty countries medal counts up through today (Monday, August 5th). The top four countries actually remain in the same order but Japan drops from fifth to eighth. South Korea jumps up from 7th to 5th due to 11 gold medals. The biggest increase is Kazakhstan which shoots up from barely making the list at #20, almost all the way into the top ten at #11.The biggest fall is by Canada from 12th to 16th. Oh, and if he were a country he’d rank 14th overall because Michael Phelps' medal count at these Olympics Games is four gold and two silver.

I’ve shared my Excel spreadsheet on Google docs and listed out the Olympic medals by country (as of the morning of August 5th - I will try to keep this updated but no promises!). How would you weight each medal against the others? Comment below and share any of your more interesting Olympic medal counts!


Check out our Downloads page for more sports templates and join our mailing list to be notified about new posts and spreadsheets.