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Author Topic: am I merely lucky?  (Read 692 times)
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North Carolina, USA
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I have a confession to make. Recently I've started paying attention to current ratings, etc, and I've realized that by now my arduino should have broken several times over, or at the very least I should have some dead pins. Several times I've hooked up low impedance speakers straight to a digital pin (I still do this as nothing bad has happened...), I've accidentally connected 5V directly to ground  :-[ , and done other such things where I should have considered the current draw (seeing how many leds I could light up without a resistor... oof.) But no smoke, no dead pins, no nothing. Am I just really lucky or is the arduino just sturdier than the average bear?
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Am I just really lucky or is the arduino just sturdier than the average bear?

A little of both most likely.  smiley-wink

I've found Atmel processors to be pretty rugged and forgiving, however anytime you exceed maximum specifications you are at risk for damage. As far as shorting the +5vdc to ground, the voltage regulator (if using the external power connector) has short circuit protection built in and if using USB +5vdc there is a thermofuse (500ma rating) on the board to protect your PC usb port.

Lefty
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On the glass-is-half-empty side of things, these "stresses" to the processor do tend to be cumulative, and it may well fail "for no reason" at some point in the future. It's very common to see postings from people that basically read "I can't program it anymore, but it was working 5 minutes ago!". So you are lucky....for now smiley

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The Gadget Shield: accelerometer, RGB LED, IR transmit/receive, light sensor, potentiometers, pushbuttons
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yeah, that's what I figured. It took me a while, but I finally figured out that the message saying "a device connected to the usb port is drawing too much current. it has been disconnected" was a bad thing. Then, I learned how to use a potentiometer correctly! (ie NOT having ground in the middle  ;D)

Assuming the current (pun!) abuse continues, is the chip itself the only thing at risk, assuming the whole thing doesn't catch on fire? Like will little smd components blow and I won't notice? That'd be a bummer trying to find what was wrong.
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....postings from people that basically read "I can't program it anymore, but it was working 5 minutes ago!"......

Reminds me of when I used to fix TVs 40 years ago. the customer would often say " there cant be much wrong with it, it was working last night "  What a coincidence !  just the day before they phoned us !......
« Last Edit: November 11, 2010, 10:15:42 am by John_Smith » Logged

With my mobile phone I can call people and talk to them -  how smart can you get ?

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is the chip itself the only thing at risk,
Mainly although the USB / serial bridge can fail as well by doing things like taking too much current from the 3v3 line. Also people have blown up their USB ports on their computers as the degree of protection is not perfect.
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They are pretty robust. I make changes to bread board circuits while running all the time. Like I'll disable or enable part of the circuit trying to debug it. I have burned out some pins on the Arduino processor, but the only error I really worry about is the USB current overload. I don't want to mess up my laptop.
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