Wouter at 10:27, 25 June 2009

2009-06-25T10:27:42Z

Wouter at 10:22, 25 June 2009

2009-06-25T10:22:46Z

New page

<pre>
import win32com.client
import time

#-------------connecting procedure----------------
print 'mobi8 heartbeat counter demo'
print 'W.Pasman 24june 2009'

mobi8=win32com.client.Dispatch("PortiSerial.SerialSource")

print "connecting with mobi8..."

mobi8.ComPort="4"
SerialNumber = mobi8.FrontendSerialNumber
if SerialNumber==-1:
raise Exception("can not open connection with mobi8."+
" Try to reconnect the mobi8 device via bluetooth")

NrOfChannels=mobi8.GetFrontendNrOfChannels()
HighestSampleRate=mobi8.SampleRate
print "mobi8 connected with "+str(NrOfChannels)+" channels, max samplerate="+str(HighestSampleRate)

#----------- set up the sampler -------------

ReceivedSamples=0
DesiredSampleRate=HighestSampleRate/4 # samples/s
SamplingTime=30 # seconds total measurement time.
mobi8.SampleRate=DesiredSampleRate
error=mobi8.StartAcq(DesiredSampleRate)
print "returned:",error

#-------------- sample heart beat rate calculator----------------
prevSample=0 # for very simple highpass filter
beattop=10000 # the peak height of hp-filtered signal.
heartbeat=0 # counter to determine length of peaks

heartTime=1 # nice start value for avg time between heartbeats
prevBeatTime=time.time()

while ReceivedSamples < SamplingTime*DesiredSampleRate:
Periods,samples=mobi8.GetSampleRecordAsVariant()
if Periods>0:
ReceivedSamples = ReceivedSamples+Periods
#print Periods
for sample in samples[0]:
d=sample-prevSample # compute high-pass filtered signal
if d>beattop and ReceivedSamples > 500: # trash first samples
beattop=d # update max peak height
print beattop
if d>beattop/3:
heartbeat=heartbeat+1
if heartbeat==3:
thetime=time.time()
heartTime=.9*heartTime + .1*(thetime-prevBeatTime)
prevBeatTime=thetime
print "heartbeat!", 60/heartTime, "bpm"
else:
if heartbeat>0:
heartbeat=heartbeat-1
prevSample=sample

#-----------------disconnect --------------------
print "closing down connection"
error=mobi8.StopAcq()
error=mobi8.ReleaseSerialPort()

print "ended"

</pre>

@@ Line 57: / Line 57: @@
            print "heartbeat!", 60/heartTime, "bpm"
        else:
-         if heartbeat>0:
+         heartbeat=0
        prevSample=sample

Mobi8PythonHBR - Revision history

Wouter at 10:27, 25 June 2009

Wouter at 10:22, 25 June 2009