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Author Topic: Shorted out Uno while successfully running soleniod actuation sketch  (Read 626 times)
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Tucson, AZ
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Think I ‘bricked’ my arduino uno. I’m a newbe and I succeeded in getting my first project working ( solenoid actuated by modified Blink.pde sketch). However, I tried to use a multimeter to measure the voltage on my breadboard and I managed to power off my PC. My test leads must have transmitted the stored current from the solenoid.

After powering up my laptop, I hit the uno’s reset button.
Uno's On LED is green.
P13 LED does not blink. Also, the arduino uno will not respond to the previously successful solenoid.pde nor blink.pde. Initially, the chip on the arduino is very hot to the touch.
The message I receive when trying to upload blink.pde to uno is:
java.lang.NullPointerException
   at processing.app.debug.Compiler.execAsynchronously(Compiler.java:299)
   at processing.app.debug.Compiler.compile(Compiler.java:182)
   at processing.app.Sketch.build(Sketch.java:1515)
   at processing.app.Sketch.exportApplet(Sketch.java:1555)
   at processing.app.Sketch.exportApplet(Sketch.java:1524)
   at processing.app.Editor$DefaultExportHandler.run(Editor.java:2293)
   at java.lang.Thread.run(Thread.java:619)
A second upload, results in no errors & uno's RX/TX led’s blink to indicate communication.
However the P13 LED which is supposed to blink is not blinking.

I ran the loop back test.
Result is RX LED on Uno blinks; but nothing is echoed back to Serial Monitor.

How can I determine if my Uno is bricked?
Is it possible the bootloader is corrupted?
If it’s a hardware issue, Is it possible to  identify & replace the damaged component?
Thanks,
Steve
Win 7 x64
« Last Edit: October 02, 2011, 07:24:31 pm by sfroach » Logged

Fort Lauderdale, FL
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Quote
Initially, the chip on the arduino is very hot to the touch.
Which chip?  The ATmega?

If your ATmega is removable, remove it.  If the PC recognizes a Uno is attached, then the board and 8u2 (serial to usb) is working.

If anything on the board is hot (or even warm) to the touch, when connected to usb and no other hardware is connected, then that chip is likely dead.
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Think I ‘bricked’ my arduino uno. I’m a newbe and I succeeded in getting my first project working ( solenoid actuated by modified Blink.pde sketch). However, I tried to use a multimeter to measure the voltage on my breadboard and I managed to power off my PC. My test leads must have transmitted the stored current from the solenoid.

It's difficult to say exactly what happened, but for the future, here are some things to keep in mind to prevent this from happening:

1. Never hook up or disconnect wiring, sensors, power, etc - while things are in a powered state. It is best to have a switch in between your power supply and the device being powered that you can flip to "off". Note: Do not assume that the power switch on a benchtop power supply is the same thing as an inline switch; it may or may not be (check your manual). For instance, I have a small adjustable benchtop supply that, when the power is flipped off, outputs a high-voltage (around 100 volts - even if the power supply is set to 5V regulated) pulse on the outputs. This is mentioned in the manual, but before I knew that, I had already blown one LED I was playing with (no big loss).

2. When you need to put a circuit under test (with a multi-meter or an oscilloscope) try not to do so while the device is operating; instead, hook the testing equipment's probes up to the circuit and verify everything (no shorts or such due to the probes or making the connections), then apply the power. Do not move the probes or anything else while under the test.

3. If you must probe while the circuit is powered, use a single probe -only-. Turn your circuit off, and connect your "ground" probe to the nearest ground for the area you will be probing in, verify the connections, then apply power, and probe with the single "positive" probe. This will reduce the possibility of inadvertent shorts and such from occuring.

Finally: Observe the "one hand" rule when probing any circuit (item 3 should take care of this); your other hand should be "in your pocket" - that is, away from the circuit under test, and not resting on any part of the circuit, or any grounded metal, etc. Get into this habit early, if you have not already done so. I know it may not seem like much when you're only playing with 5-12 VDC circuits at low currents, but by being in the habit - should you in the future work on some device or circuit that uses higher voltages, or has a beefier current supply, you'll greatly lessen the chance of finding yourself on a trip to the ER or morgue (due to current traveling from one hand, across your chest/heart, and down the other - leading to cardiac arrest, defibrillation, etc).

Good luck, and I hope you're able to restore your Arduino...

smiley
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Tucson, AZ
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I removed the chip. Win 7 beeped when I plugged in the Uno.
Is this what you mean by 'PC recognizing' uno?

Uno on LED is green. All others are dark.

Uploading 'blink' resulted in following error:
Binary sketch size: 1018 bytes (of a 32256 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

Serial Monitor characters do NOT echo. But the Uno RX LED blinks.

The ATMega 328 chip was very hot to the touch. So do you think it's worth replacing it or just get another Uno?

Thanks,
Steve
  
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By recognising the Uno, he means can you see the Uno listed in your hardware devices list (or whatever Windows 7 calls it).
As your Uno has the DIL removeable Atmega328 arduino chip, it would be cheaper to replace that rather than buy a whole new Uno, although it is possible that other components have also been damaged. If/when you purchase a replacement Atmega chip, make sure it is an Arduino bootloaded chip, not just a blank Atmega328P.

Texy
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Win 7 does recognize the Uno as COM9 via Control Panel > Device Manager .

The write up of what to remember for next time is excellent!

Ordered 2 new Atmega328 chips, 28 pin with bootloader, from Sparkfun.
The description talked about speeding the micro up; but I think that was in reference to other micros.
Is this chip apt to be a drop in replacement on my board?

Thanks, thanks, thanks,
Steve
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Quote
Initially, the chip on the arduino is very hot to the touch.
Which chip?  The ATmega?

If your ATmega is removable, remove it.  If the PC recognizes a Uno is attached, then the board and 8u2 (serial to usb) is working.

If anything on the board is hot (or even warm) to the touch, when connected to usb and no other hardware is connected, then that chip is likely dead.

No, it might just be in latched-up state (sometimes happens with CMOS if signal voltages higher than power supply) - power down and retry cautiously.  If still getting hot something is wrong.

Also there is a possibility of a short-circuit somewhere leading to overheating (and maybe damage) - a multimeter is invaluable in tracking these down.

A good rule when connecting up circuits is "don't apply power until you have double checked the whole circuit".  This saves money over time!
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I popped in a new ATmega328 chip with installed bootloader from Sparkfun. The blink.pde works ok.

SYmrhs328 is running without any noticeable heat to the touch.

Does anyone know of a test .pde I can run to determine if some other hardware components were also damaged.

Thanks for all the help,
Steve
« Last Edit: October 07, 2011, 10:53:15 am by sfroach » Logged

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The only other hardware is the 8u2 and analog (power supply switching).  So I'm not sure a test sketch would do any good.
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