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...