Practical uses of Excel for a cylinder head flow bench, ECG filter, antenna plotter, BG7TBL Spectrum Analyzer, bicycle ride analyzer and to facilitate automated classroom testing of reading.
ECG FILTER.xls takes a file portion from the  ECG  and filters appropriately to make a handy ECG trace. (kit detail from: http://archive.siliconchip.com.au/cms/A_103787/printArticle.html) This workbook was the first step toward porting the software below to Excel's VBA, getting the filter code worked out first.
RF6.xlsm takes a field strength file of 360 readings obtained as an antenna is swung through a full circle. It is displayed on a standard polar plot, and the entire plot can be rotated several degrees each way to correct the alignment if slack exists in the rotor sensor.
An AVR was connected to various onboard sensors, which saved a vehicle's acceleration run to file. The file was then analysed by this Excel program to plot the developed HP curve. Horsepower looks a  little odd! Later, I sought to incorporate turbo boost pressure, and used an accelerometer chip.
You would need the NETCOMM.OCX to develop this idea, and will be found in PICAXE to EXCEL KIT project download. 
Instead of the normal ecg leads, using just two thumb pads gives what professional users have called, "a very useful trace." The Excel sheet was built in anticipation of this kit feeding into Excel via a serial interface, not yet built, and of the need to implement filters in VBA to obtain a useable trace.
  Below shows the setup and report page. The slider at center allows you to choose a level for your ride to be compared against published RAMP test expectations. A separate page imports your GPX file, and dumps it onto a "scratch" sheet for processing. I realise RAMP tests are quite different to road work, so this software looks at your ride in small blocks similar to the standard RAMP tests.
  This software is the simplest, and because my Bicycle Power Meter also appends tilt angle, distance and barometric height to the end of the GPS string, I then use an enhanced version of this software. When my wind speed sensor is included, it will then become very similar to the iBike method which uses basic energy equations.
I am also investigating intercepting the Polar heart rate signal and incorporating that also.
A special program for a handicapped person, who had enough wrist movement to move a mouse. Excel shows a visual keyboard, and internal e-mail sender. Caution, some operating system setups may not allow you to directly email from excel. This probably "reinvents the wheel," as concept keyboards abound, but is a useful study into how it's done in Excel.
Project: Easy communication for a handicapped friend.
Status: Ongoing
Just handy for a look at how VBA functions are used to build a stopwatch and generate random numbers.
Project: Classroom use. Random numbers, randomly pair students, and other odd clasroom uses for Excel
Status: Ongoing
The old Ayres test was standardised using 70000 students. It is ancient, but I have adjusted it to give reliable results. You can generate Level tests, or a Grading test. AuVels scoring is given.
Project: Classroom use.Generate tests and Score the old Ayres Spelling test
The old Danials and Diack "Graded Test of Reading Experience" is slightly changed to remove archaic language, and turned into a self administering test.
Project:  Classroom use.Self administering lower grades reading tests
The Burt test. Not quite self administering, needs an aide to press + (correct) or - (incorrect). One workbook used original norms, The V2 workbook uses some locally revised norms explained  in an internal note. Locally, the NZ norms were not tracking other test results in our schools.
Project:  Classroom use.Self administering Burt Test
Every student's profile is updated via Teacher Gradebooks (Excel based), and automatically read into the Master Gradebook twice a year. NAPLAN, VCAA Online Testing, and AuVELS results are also read in, and this gives the basis for analysing school progress and underpins curriculum decision making.
As a bonus, an Excel dashboard (below) is available instantly for any student, giving the child's entire educational profile. This has been a development over five years, and used freely by several schools. The lack of design uniformity is because people kept on coming  up with things to add, which had to be "tacked on". Sorry, the code is not public, but shows what an Excel flat file database can do in an educational setting.
Project:  Classroom / Admin use. Instant access to student achievement profile
A workbook that shows you how to create and incorporate some very useful graphical displays that are not part of the standard Excel package
EXCEL SOLUTIONS
ECG.C is the original source code for a dos program to run the Silicon Chip ECG kit, and do a graphical display. You will need the SMPLUS menu, link on "ARDUINO" page to compile this. I intend to move it to Excel, implemented in VBA. See DOS screen below.
First traces from the thumb pad whilst developing the DOS based ECG software. Three wire plots will give exacting traces, but just a little more work. Before building the ECG circuit, make sure you read a good ECG primer first so you will know just what you are looking at!.
Try http://www.anaesthetist.com/icu/organs/heart/ecg/Findex.htm
RF6.xlsm was transferred to VBA from a stand alone DOS program. Source code in "C" here for those interested
Wardies Ride Analyser.xls, analyses performance in chosen time blocks
Tachistoscope.xls would assist educators.  Effectively electronic flash cards for language development.You place a list, and you can auto step, or manually step through the list
EXCELtoELM327.XLS.This is provided to show you roughly how to read your vehicle's OBDI codes (diagnostic codes). It works, but is not a fully completed program. The whole book developed without plan from a simple function to have Excel talk to my commercially available ELMSCAN-5, which uses the ELM327 chip, which is cheaply available. REMEMBER You will need NETCOMM.OCX loaded first, before trying to open this program!
Four screen grabs of unusual, but useful graphical displays for Excel
Source code in C to produce this Polar antenna plot
I had a particular program that I did not want others to move to different machines. It's quite possible to achieve, but you have to add the workbook to the computer yourself, use the macro buttons to obtain the CPU ID, HDD Id,and User, then paste in the codes to the VBA project before locking the project. Cumbersome, but a handy set of functions if you need them.
Project:  Lock  an Excel workbook to a particular PC
Project: Analyse rider performance against common standard ramp tests
Project: Exploring filters for ECG
Project: BG7TBL Spectrum Analyzer board controlled directly from Microsoft Excel

  Features an easy to drive, two hundred point sweep system, with cursors and save to file ability. (If you really want more points, I  have included functions to do that, but I have built much specialized RF instrumentation, and a two hundred point sweep has always been adequate.)
   Because of the capabilities available via Excel's VBA, there is plenty of opportunity to write all sorts of additional functions to to develop the platform further. As is, it should complement the original software supplied with this board for simple tests of filters and antennas, similar to those found in "Low-Cost RF Tuning and Testing from 138MHz to 4.4GHz", (http://www.y1pwe.co.uk/RAProgs/USB%20138M.pdf)

The wonderful sCOMM32 (http://www.comm32.com/) takes care of  communications between Excel and the BG7TBL analyzer.
sCOMM32 must be loaded and registered before running this program. The demo version does not expire, and a small nag screen quickly disappears.

(On my Arduino pages there are several projects using sCOMM32 to communicate data to Excel)
My BG7TBL from:
http://www.ebay.com.au/itm/121581250809?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
You MUST enable macros for workbooks to calculate correctly.  For your protection, all VBA modules are unlocked
  Above Right: Simple setup and comm check for the BG7TBL spectrum analyzer. Left is a 200 point sweep, displaying antenna response to a simple oscillator at 100 mHz, the cursors showing a 3 dB bandwidth of 0.57 mHz