I have simplified the program some what and speed-ed it up. I was
missing some of the compression pulses at 10 milliseconds.
Here is the new program with comments.
. Cls '.........................clear the screen
3 Open "press.dat" For output As #1 'open a file on the SD card
'..............................................................upper
and lower case does
'...............................................................not
matter in MM BASIC.
5 SetPin 9,1 '............set up pin 9 for A 2 D input 6 Print
"rotor 1" '......print on the screen 7 Print Date$ '.......print on
the screen 8 Print Time$ '........print on the screen
SetTick 10,30 '.....wait until 10 milliseconds has past
'............................and then go do it.
10 'bakgr '.........twiddle thy thumbs 15 GoTo 10
30 For x = 1 To 8 '....sample & record 8 readings as fast as
possible '.............................probably as often as a few
dozen microseconds.
press = Pin(9) Print press ; '.......print on the screen Print #1,
press; '.....record it Print #1, ","; Next Print
'..............print a carriage return on the screen Print #1,
'...........record a carriage return in the file
35 IReturn '......software interrupt return
Here is a picture of the output on the screen. These numbers need to
be doubled because of the voltage divider. As you can see there are 3
pulse in a row indicating this rotor is OK.
The numbers data file is an ASCII or txt file so you need to open
it with word pad. It is zipped because it would display on your cell
phone as one great big long message.
Paul Lamar
Hi again Paul
Looking at the resolution of the chart, how about changing the interrupt
to 1
mSec.
Steve
Yes I think that would be better.
Paul Lamar
That works. One millisecond.
I installed a pot to check the A 2 D and it is working as advertised.
I read the fine print in the sensor doc and .5 volt is as low
as it goes so subtract .5 from all that data I sent.
Please re plot it. I think that will look more reasonably.
The span is only 4 volts. so the divider will be 3.5/4 or
0.85 and not .5.
When all else fails read the doc :-)
Another problem is the throttle was not open so it had trouble
filling the chambers.
I have a plumbing problem so until I get that fixed more data
will have to wait.
Paul Lamar
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