Stimulus Response Timing Measurement

Archiver

Hello All,
I am new to the stamp list and after reviewing many pages in the
archive of this list have a question which I hope you can help with.
I have a BSII. Need to build a device where the BSII turns on a
light ... then a user must hit a switch..the time between stimulus
and response is stored.. the stamp then activates another light and
the user turns a switch under that light...and so on for 9 different
inputs. The subjects may or may not be impaired so timing could be
in the tenths of seconds (requiring 1/100 resolution) or in the 2
minute range. Any ideas on how to do this cleanly and efficiently
would be appreciated.
Thanks!!
VF

Archiver

>Hello All,
>I am new to the stamp list and after reviewing many pages in the
>archive of this list have a question which I hope you can help with.
>I have a BSII. Need to build a device where the BSII turns on a
>light ... then a user must hit a switch..the time between stimulus
>and response is stored.. the stamp then activates another light and
>the user turns a switch under that light...and so on for 9 different
>inputs. The subjects may or may not be impaired so timing could be
>in the tenths of seconds (requiring 1/100 resolution) or in the 2
>minute range. Any ideas on how to do this cleanly and efficiently
>would be appreciated.
>Thanks!!
>VF

One way to do this would be by use of an external timer chip, such as
the ones sold by Al Williams or by Peter Anderson.

If you do not want to use an external chip, the Stamp alone is
capable of running a timing loop with about 1 millisecond of
resolution, although it may take a little bit of calibration to get
the best accuracy.
http://www.emesystems.com/BS2speed.htm#longpulse

BASICally

high p8 ' turn on light on p8

' now time how long input pin p0 switch stays high (up to ~45 seconds)
xc var word
loop: ' ~1426 loops per second, 7.013E-4 seconds per loop
xc=xc+1
if in0 then loop ' count until in0 input goes low
debug dec xc**45960,cr ' ** converts the count to straight milliseconds
' you will need to calibrate this value

The reason you need to calibrate it is (1) individual stamps have
slightly different operating frequencies (which may depend to a
fraction of 1% on operating temperature) and (2) the exact timing
depends on a which pin you use for the input, where the variable is
in memory, how many subroutines there are in your program etc. etc.
But once you have it done, the timing will be very stable from then
on out.

-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com