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Basic stamp 2 going heywire — Parallax Forums

Basic stamp 2 going heywire

BornaBorna Posts: 36
edited 2014-09-11 19:24 in BASIC Stamp
Hello all,
I have made a small model engine which I am using basic stamp 2 to control the RPM using solenoid which will act as a governor. The engine also use CDI module to provide ignition to the spark plug. The CDI is not in any way connected to basic stamp and work independently. The original code didn't work, there fore I made the code very simple to see if something else is the issue.

When the engine is not running the below code works perfectly. The solenoid become active for 3 secs and inactive for 2 sec with no issues.

However when the engine is running, the solenoid is either become active and stays active continuous or never becomes active at all.

' {$STAMP BS2}
' {$PBASIC 2.5}

Gov PIN 14 'if this pin goes high, it will activate the solenoid
do
HIGH Gov
PAUSE 3000
LOW Gov
PAUSE 2000
LOOP
So this code works as long as the engine is not running.
so I am thinking the following
1.maybe the engine vibration interfere with the basic stamp? From picture you can see the stamp is connected at the bottom of the engine panel
2.maybe the high voltage from the CDI interfere with the stamp?

Here is the video of the engine running
https://www.youtube.com/watch?v=SpEAWje8n5Y

Any idea if the 2 above case could cause the stamp to go haywire?

photo 2-1.JPG
photo 2-1.JPG
640 x 480 - 125K

Comments

  • Ken GraceyKen Gracey Posts: 7,395
    edited 2014-09-10 20:47
    It sounds like the BS2 is resetting because you're not getting past the HIGH line of code.

    Have you scoped out the BS2's power supply? How are you powering the BS2 exactly?

    Ken Gracey
  • Mike GreenMike Green Posts: 23,101
    edited 2014-09-10 20:50
    1) The wires on the breadboard might be susceptible to vibration, but not the rest of the board or the Stamp itself.

    2) High voltage from the CDI might indeed be interfering with the Stamp. Specifically, electrical noise can cause the Stamp to reset and the program to start over from the beginning. You would need to identify what wires in the picture carry high voltage or carry power to the CDI. Typically, you would shield the logic circuitry (the Stamp board and what's connected to it) and add filtering to the power supplied to the Stamp board.
  • BornaBorna Posts: 36
    edited 2014-09-11 11:34
    Ken Gracey wrote: »
    It sounds like the BS2 is resetting because you're not getting past the HIGH line of code.

    Have you scoped out the BS2's power supply? How are you powering the BS2 exactly?

    Ken Gracey
    I am using 9 volts battery. As long as the engine is not running the code works. the 9 volts battery only provide power to the stamp and nothing else.
  • BornaBorna Posts: 36
    edited 2014-09-11 11:41
    Also as Mike suggested, this could be the high voltage from the CDI. how far should be the distance between the basic stamp and the CDI? Maybe to test that possibility I'll try to move the stamp board away from the CDI
  • davejamesdavejames Posts: 4,047
    edited 2014-09-11 11:53
    Borna - do you have an oscilloscope?

    As Per Mr. Gracey's comment, you need to observe the Stamp's supply lines, and checking the data lines would be a good idea also. You'll be looking for large amounts of noise.

    Anything other methods of debug will be "working in the dark", and a guess at best.
  • 72sonett72sonett Posts: 82
    edited 2014-09-11 13:59
    Is there a diode across the solenoid?
    Did you use shielded wire to connect pin 14 to the solenoid?

    From the youtube link I understand the solenoid locks the push rod so the valve stays open and the engine stops.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2014-09-11 14:45
    Many questions could be answered at one with a schematic. I would recommend posting one if you have it. :thumb:
  • BornaBorna Posts: 36
    edited 2014-09-11 16:05
    Thank you all for the reply.
    The issue is fixed. main reason to the problem was that the battery was attached to the CDI unit. Once I removed the battery away, then things started to work.
    you can see a video as how the solenoid works

    https://www.youtube.com/watch?v=Un0HZwI8pwg&list=UUL8gj_06zIsMRLY-U6zQItA

    The logic is I have a hall sensor that measures the RPM, if RPM goes above 2200, then it will activate the solenoid for 1 sec. Now that everything is working I can place a better logic.

    ' {$STAMP BS2}
    ' {$PBASIC 2.5}

    Gov PIN 14
    SpeedIn PIN 3
    SensorPulses VAR Byte
    rpm VAR Word

    DO
    LOW Gov
    rpm = 0
    Capture CON 1000
    SensorPulses = 0
    COUNT SpeedIn, Capture, SensorPulses
    rpm = (SensorPulses * 60)
    IF rpm > 2200 THEN
    HIGH Gov
    PAUSE 1000
    ENDIF
    LOOP
  • ercoerco Posts: 20,257
    edited 2014-09-11 19:24
    Congrats and great project Borna! Hit & miss engines are very cool. Like
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