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Stupid Prop Tricks — Parallax Forums

Stupid Prop Tricks

rjo_rjo_ Posts: 1,825
edited 2009-02-26 22:44 in Propeller 1
I hate being told what to do... my kids tell me what to do... my ex tells me what to do.

So when it comes to my Prop... I get to do whatever I want.

I have a Telit unit on a USB breakout board from Sparkfun... and I was in pure misery until I connected it to a Prop.

I'm down to 2 ProtoBoards, so I really didn't want to sacrifice one of those... but I have a bunch of Prop chips sitting around.

So, just for the heck of it, I hooked up the ground and 3.8V(which actually measures 3.96V) from the Sparkfun unit to a Prop on a breadboard... and 24 hours later, all the pins still work!!!

I'm going to let the thing cook until it fries. Any guesses how long it will work?

Rich

Comments

  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2009-02-25 16:40
    The Propeller is very robust! I'll bet it works indefinitely. [noparse]:)[/noparse]

    OBC

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  • rjo_rjo_ Posts: 1,825
    edited 2009-02-25 16:47
    me too[noparse]:)[/noparse]

    Anyone else gotta guess?
  • SRLMSRLM Posts: 5,045
    edited 2009-02-25 17:05
    If it's been working for 24 hours already, I doubt that (at the same environmental conditions) it will ever stop.
  • BaggersBaggers Posts: 3,019
    edited 2009-02-25 18:29
    I to doubt it'll be killed, the Prop is a bit of a monster, and not just in what it's capable of, but in what pounding it can take also [noparse]:D[/noparse]

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  • Michael O'BrienMichael O'Brien Posts: 55
    edited 2009-02-26 05:09
    I accidentally fed 9v into one of my 40 pin dip props - now it heats up past a comfortable temp in 5 seconds - I use it as a prop prop.
    One of my proto boards underwent a lot of soldering and handling, and worked well - but again I accidentally touched power to 9 volts and the board will not respond to F10 or 11 programming - I put it in the freezer - what's wrong with me?

    So one of the morals of this story is that I am glad that we can order enough of these excellent chips and grab the next one off the rack.
    I like your experiment - these kind of things would be hard to do with desktop cpu's
    /michael
  • mctriviamctrivia Posts: 3,772
    edited 2009-02-26 05:21
    i accidentally put 9v to my first propmod. blew the chip in no time. other then that the prop is a great chip. Think I will be adding an optional BZT52C3V9-7-F to my next batch of propmods as an over voltage protection.
  • DroneDrone Posts: 433
    edited 2009-02-26 06:19
    BZT52C3V9-7-F is a 3.9V Zener, typically SOD-324 package, 0.42 ea. in qty.-1 from Mouser. You will need to add a series current limiting resistor for the Zener to work as over voltage protection, otherwise the Zener will burn out allowing the over voltage to hit the Propeller. I use a low drop-out (LDO) regulator instead.
  • mctriviamctrivia Posts: 3,772
    edited 2009-02-26 06:30
    i realize it would not protect for long. it is only for those "oops i am an idiot" moments. Plus it was the only one i could find to fit in the 200mil I thought I had free. Just realized I have 400mil some were else. any one know what package might fit?
  • mctriviamctrivia Posts: 3,772
    edited 2009-02-26 09:27
    found this. 1SMA5915BT3G much more powerful and slightly cheaper.

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    Need to make your prop design easier or secure? Get a PropMod $50CAN has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module.
  • rjo_rjo_ Posts: 1,825
    edited 2009-02-26 12:48
    thanks guys
  • Ken PetersonKen Peterson Posts: 806
    edited 2009-02-26 13:11
    I designed a board to use an LM317 regulator. I replaced it with a LMS1587 3.3V fixed regulator, because it was pin compatible and I didn't need to add the resistors. What I forgot to do is add a jumper in place of the ADJ resistor. Ooops. 12V straight to the Prop. I only had it connected long enough to measure the voltage, but that was plenty of time to ruin it.

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  • PhilldapillPhilldapill Posts: 1,283
    edited 2009-02-26 19:13
    In theory and in regards to semiconductor devices, the ONLY thing that damages them is overheating, correct?
  • Mike GreenMike Green Posts: 23,101
    edited 2009-02-26 19:38
    Nope, overvoltage can directly damage them by blowing holes in insulating layers (like gates). Overcurrent can melt or explode (microscopically) wires on the chip surface (or sometimes buried in layers just under the surface). Too much current can sometimes cause metal migration where the electron flow causes metal atoms to move along the surface (kind of like electronic erosion) to the point where the conductor breaks.

    Post Edited (Mike Green) : 2/26/2009 7:43:44 PM GMT
  • BaggersBaggers Posts: 3,019
    edited 2009-02-26 22:44
    Rich, is it still alive and well? or showing signs of defeat? or already smoked?

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