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some smoke and a very ticked of teenager — Parallax Forums

some smoke and a very ticked of teenager

science_geekscience_geek Posts: 247
edited 2008-10-21 20:10 in Propeller 1
ok, so funny thing, i was working on the last few bits of a school project that included a parallax ping sensor. i hooked it up to a 5v dc power source just as the front of the ping states. it went BOOOOM, and 2 of the orange things on the back exploded and spit out a big puff of smoke, i cried for a while and then wanted to know why it happened. i took out my voltmeter, and check the voltage at the source i plugged in the ping, i get 5.13ish volts, i know for an absolutely positivly so help me god that i hooked it up right, i dont know why this happened, has anyone here ever had this happen or know why it happened. i had droped it from about 10ft early in the night, could this have done it.

Comments

  • P!-RoP!-Ro Posts: 1,189
    edited 2008-10-21 01:53
    If those "orange things" are capacitors, you probably just hooked up the 5v the wrong direction and caused them to overheat. See if you can return it to Parallax to have it fixed.

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    Pi Guy
  • science_geekscience_geek Posts: 247
    edited 2008-10-21 15:00
    i dont think they will, ive had it for almost 4 years or so, it was old, i was just shocked that it exploded cause i have had it working before
  • TeslaTesla Posts: 55
    edited 2008-10-21 17:21
    You could take it as a challenge and try to fix it yourself. If you did reverse the caps, then it should be an easy fix.

    Word to the wise...... ALWAYS check you psu for proper voltage before you hook it up. Had one labled 9VDC one time and it was putting out up to 23v and fried the scale we use for ups shipping at my work.
  • sylvie369sylvie369 Posts: 1,622
    edited 2008-10-21 17:56
    Tesla said...
    You could take it as a challenge and try to fix it yourself. If you did reverse the caps, then it should be an easy fix.

    Word to the wise...... ALWAYS check you psu for proper voltage before you hook it up. Had one labled 9VDC one time and it was putting out up to 23v and fried the scale we use for ups shipping at my work.
    I recently had a device that needed 12V, and I bought a wall wart marked as putting out 12V. It was then that I discovered that most of those wall warts put out quite a bit more voltage than the label indicates. The first one put out 17, the second one I bought put out 18, and the third one I bought put out 21 volts. Fortunately I didn't fry anything, and I learned that you need to put the output of wall warts into a circuit with a voltage regulator before you use it.

    I hope that was a "typical rookie mistake", right?
  • Paul BakerPaul Baker Posts: 6,351
    edited 2008-10-21 18:06
    The problem is when an engineer (or layperson) grabs a power supply but doesn't look for the word "Regulated" on it. Unregulated supplies only provide the specified voltage when the current rating is drawn from it. If you grab a 9V 300mA unregulated supply, if you draw less than 300mA, the voltage is greater than 9V, and if you draw more than 300mA, the output voltage will be less.

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    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2008-10-21 18:13
    science_geek said...
    ok, so funny thing, i was working on the last few bits of a school project that included a parallax ping sensor. i hooked it up to a 5v dc power source just as the front of the ping states. it went BOOOOM, and 2 of the orange things on the back exploded and spit out a big puff of smoke, i cried for a while and then wanted to know why it happened. i took out my voltmeter, and check the voltage at the source i plugged in the ping, i get 5.13ish volts, i know for an absolutely positivly so help me god that i hooked it up right, i dont know why this happened, has anyone here ever had this happen or know why it happened. i had droped it from about 10ft early in the night, could this have done it.

    Can you post a picture of the sensor with the blown parts? If they are tantalum caps then yes, those can and will go out in flames if you accidentally reverse the polarity. Tantalum caps as well as polarized electrolytic caps can do this when the polarity is reversed. Tantalum usually seem to go up in a burst of flames for a moment while electrolytic caps usually explode in a loud bang. Anyone who has worked with electronics for any length of time usually runs into this at least once. I remember this happen with an electrolytic in High School electronics and have seen the Tantalum a few times since then.

    You might be able to send in the sensor for repair. If it is just a couple of caps then as someone already suggested you might be able to just replace those parts to fix it.

    Good luck,

    Robert
  • TeslaTesla Posts: 55
    edited 2008-10-21 20:10
    One nick name i have heard for Tantalum cap is "tantrum caps" because of how sensitve they are.
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