I have experienced several times that PCBs with an Arduino chip no longer function properly when in contact with water or when touched with fingers during use. The reason is that this leads to disruption of the clock oscillator and can lead to permanent "damage" as the program memory becomes corrupted. Sometimes the product still works initially, but then errors occur in the microcontroller.
Sometimes it is sufficient to re-upload the sketch, but the bootloader may also be corrupt and need to be re-burned.
The clock generator of a microcontroller is particularly sensitive, and its operation can be disrupted if the pins of the crystal are accidentally touched. The processor can then exhibit unpredictable behavior. The same can happen in the presence of moisture. Upon drying and restarting, the processor should, in principle, function normally again. However, this is not always the case. I have tested what can happen when the clock generator is disturbed: the processor can accidentally write to the program memory, rendering the chip essentially useless, and the product will no longer function well. To address this issue, the chip needs to be reprogrammed by the manufacturer.
The above poses a problem: a product with a microcontroller can be "damaged" by accidental or intentional contact with the oscillator pins or by temporary contact with water. For the manufacturer, this represents a risk as they may be liable for the repairs.
To avoid problems, the crystal area must be kept compact and covered with a conformal coating.
See my article Arduino tips and troubleshooting
Typically, I don't touch electronics that are running knowing that my touch can frack something up.
Why do you find it necessary to touch pins of an actively running circuit? Your fingers are conductors that can short things out. Also, extraneous current flowing through you can damage you.
Pure water is not conductive. Typically, water has other items in it that are conductive and even corrosive to electronics. Water is known as a solvent.
May I ask, are you really that naive about water and electronics?
For your edification,
Oh to answer the questions posed by the OP,
I do.
The US government does.
Oh and I'm sure you know about it as well. Why don't you store your smartphone in an aquarium at night?
Something else you may not be aware of, your body can carry a static charge?
Why do you find it necessary to touch pins of an actively running circuit?
For example, to feel whether a part is not too hot
During measuring and experimenting I come into contact with electronics, at low voltage this is never a problem.
I have found out that the oscillator pins are sensitive to touch (and also to moisture). The clock frequency of the chip is then disturbed and this leads to the erasing of the memory. This is an interesting topic and I would like to know more about it.
It is an issue for warranty, because a customer can delete the memory of the atmega by accidentally touching it.
A customer had a defective PCB where the atmega appeared to be erased, presumably due to moisture. After reprogramming it worked again.
When touching energized electronics or adding moisture to energized electronics, expect the unexpected up to and including the release of the magic smoke. Your electronics is operating normally for being energized and touched or watered whiles energized.
Why would there be an issue of warranty when the electronics messes up when being touched or watered while energized when doing so displays a lack of understanding and intelligence?
The clock generator of a microcontroller is particularly sensitive, and its operation can be disrupted if the pins of the crystal are accidentally touched. The processor can then exhibit unpredictable behavior. The same can happen in the presence of moisture. Upon drying and restarting, the processor should, in principle, function normally again.
However, this is not always the case. I have tested what can happen when the clock generator is disturbed: the processor can accidentally write to the program memory, rendering the chip essentially useless, and the product will no longer function. To address this issue, the chip needs to be reprogrammed by the manufacturer.
The above poses a problem: a product with a microcontroller can be "damaged" by accidental or intentional contact with the oscillator pins or by temporary contact with water. For the manufacturer, this represents a risk as they may be liable for the repairs.
If the boot loader is overwritten then it can easily be replaced using an other Arduino ( Uno or Nano classic) programmed with an ISP code in it. Then you can use it to replace the boot loader.
Yes and when you buy a brand new car, it looses half its value once you drive it off the dealer's forecourt and temporary into a tree.
Do not forget you are buying a component here and not a product. The two have totally different liability / warranty expectations in law.
You wouldn't dream of complaining to a flour producer if you made a mess of baking a cake would you? Maybe you would?
I dont see how this is a problem.
When working on sensitive electronics on the test bench we take sensible precautions. So when I'm repaiiring a laptop I use a ground strap to control static, and remove the battery and mains lead.
In a "product" in normal use the sensitive parts are enclosed and protected as far as possible from outside interference. (until someone drowns their laptop then turns it on to see if it still works.)
Not really because the warranty and legislation protect them against such risk when the damage is due to misuse and not faulty parts.
As for moisture you can add a spray on coating, to protect the whole PCB and components against condensing humidity.
But you would normally state in a condition document the temperature range and the humidity range it will work over. Normally this will say something about condensation humidity.
In short for condensation all bets are off, in most consumer equipment.
