Hello!
I am working on a project that involves a GSR sensor. Using Arduino, I created the GSR sensor so the finger would be placed on a copper coin which is attached to the end of the wire. Is it 100% safe to get data of skin conductivity when the finger is essentially touching the electrically active wire? If not, is there an alternative to make it safe?
Advice would be appreciated! Thank you!
Generally it is safe to touch conductors in low voltage powered circuits if they are battery powered or electrically isolated from household AC. Modern computer power supplies are usually so isolated, but a laptop disconnected from the AC line is always safe.
You need two connections to measure skin conductivity.
There is obviously much more to your project than a sensor and a copper coin. At least a block diagram showing the wiring and power supply is necessary for any answer.
Paul
Most regulations consider anything less than 48V to be safe, and anything greater than 48V has to be insulated & isolated from human touch.
...One thing that can be tricky is inductors (including motors) because even with a small battery you can generate enough voltage to get a shock. That's how those prank/shock gadgets work. It's also how a 12V battery generates enough voltage for a spark plug in a car, and that IS dangerous!
As you pick yourself up off the ground!
Actually as someone who has worked on cars for a few decades, While a automotive ignition lead to the spark plug will shock the crap out of you, it typically won't drop you to the ground. Typical stock applications range anywhere from 18k-40k volts, but keep in mind there is zero amperage behind it.
A common old skool prank was to take a ignition condenser, stick the lead into a spark plug wire and crank the engine over thus charging the condenser. Then as you walk through the shop you toss it to you buddy and say catch...Inevitably when they catch it the lead will touch the casing and short out and shock the ship out of your buddy. All in good fun 
So to answer the original question, no there is no danger in touching your very low voltage coin sensor.
Thank you for all of the replies!
I want to double check before I begin- is there a safer way to build the GSR sensor rather than using the coin? Maybe Groove GSR sensor (premade) or aluminum wrap?
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