EKG Sampling Script

1
EKG Sampling Script

• John Thornton
• Brian Walden

2
What does it do?

• The psych lab in the science center runs
  experiments that sample the amplitude of brain
  waves of subjects in the experiments
• Our program utilizes pre-existing code to allow
  the user to write a script which allows them to
  run multiple samples consecutively on the EKG
  detection device in the psych lab

3
Scripting Language
Sample Script
Template test1 sec 150 hz 100 chan 0-14 write
test1a.txt Template test2 sec 30 hz 200
chan 15-29 write test2a.txt Template test3
min 1 hz 50 chan 0-29 write test3a.txt
Run test1 Run test2
Run test1 min 2 write test1b.txt
Run test2 min 1 write test2b.txt

Run test1 sec 90 write test1c.txt
Run test2 sec 90 write test2c txt Run
test3 Run test3 hz 100 chan 0-14
append test3a.txt Run test 3 sec 45 hz 150
chan 0-14 append test3a.txt

4
Scripting Language
Making a Template
Template ltnamegt minsec lttimegt hzperMin
ltfrequencygt chan ltlist of channelsgt i
writeappend ltfile namegt i is an element of
1,2,3,4,5,6,7,8,9,10
ltnamegt and ltfile namegt are strings of
characters lttimegt
and ltfrequencygt are integers
ltlist of channelsgt is a
list of ints separated by , or
ex 3,8,11-17,21-15,29
5
Scripting Language
Running a Sample
Run ltnamegt j minsec lttimegt j hzperMin
frequency j chan ltlist of channelsgt
(iUj) writeappend ltfile namegt
i is an element of
1,2,3,4,5,6,7,8,9,10 j is an
element of 0,1 (iUj) is an
element of 0,1,2,3,4,5,6,7,8,9,10
6
Program Flow Chart
Sample Reader
Final Output Files
Post Processor
Sample Container
Temp Output Files
Sample runner
7
Technical Challenges

• Making sure rate of writing output keeps up with
  reading the input
• Keeping the time between samples as small as
  possible
• Developing a powerful scripting language thats
  easy to use
• Developing in a fairly limited environment
• Understanding poorly documented code when the
  programmer is unavailable

8
What We Learned

• Smart data structures make integrating different
  parts of the program easy
• Working with non-professional code is hard
• Keeping documentation really helps

9
Future Improvements/Bugs

• Improvements
• Allowing for the user to administer a stimulus
• Additional post processing capabilities
• Bugs
• Right now you cant insert the frequency in
  samples per minute
• Improve script reader so that errors dont
  cascade