Hi,
about 7 hours ago i was experimenting with a (faulty) esp8266.
I noticed that sometimes it freezes and doesn't boot properly, the red led (that states it's ON).
I thought it was a power supply problem, so i used a atx power supply.
The esp8266 was powered with an AMS1117 3.3V linear regulator, that can provide 1 Ampere of current.
Now that's the problem, the module had the same faulty behavior.
I touched it's antenna (sometimes after this it started working properly) and i felt a tingling sensation in my hand. I then tried again touching for maybe 2 seconds, and i felt a heavier tingling, so i powered it down. The tingling stopped as i stopped touching it.
I think that the module was transmitting on the 2.4Ghz at full power, so 3.3*1 = 3.3 Watt of microwave in my finger and hand.
I am quite scared.
Now i don't feel pain or strange tingling but i don't know if i had some long term damage.
Someone have experimented this kind of damage? Should i go to the doctor?
Thank you and sorry for the long post.
PS: these modules can be unreliable and do VERY strange things, including transmitting at FULL POWER for absolutely no reason!! Be careful!
Errata corrige in the third line:
"I noticed that sometimes it freezes and doesn't boot properly, while the red led (that states it's ON) remained off"
>>989956
Oh yeah, they can be random.
If you haven't, add some caps as close to the power pins as you can. It's very jumpy with the power and some filter caps solve most of the instability issues.
Also, look up some range tests on youtube for it. It's a bit scary.
>>989956
wouldnt it burn before doing any sort of damage to you? i mean, if it was really doing that 3.3w transmit with no heatsink it would most likely burn pretty fast, right? (isnt that chip power rating about 100ma or so?)
>transmit data is like ac @ 2.4ghz
>low voltage ac tingles
can this be your explanation op, i mean the antena is bare copper
Did you earth GND or was it floating? Power supplies may have some capacitive coupling between mains and their output.
>>989956
>Someone have experimented this kind of damage? Should i go to the doctor?
You are fine. I made the mistake of touching an empty antenna port while a hand mike was being keyed (US Army commo guy) and that hurt like a motherfucker. Kept hurting for about 5 minutes after with very little drop in the level of pain. RF fucking hurts. No mark, no burn, no long term damage though.
All RF does to you is heat up the water in your flesh. Unless you do it for a long time or at very high output the worst you will get is pain. You got a tingle. Its literally nothing.
>>990034
This. The outputs of an ungrounded (plugged to an ungrounded socket) ATX power supply float at half mains voltage. It is enough to give slight shocks even to an ungrounded person and if you touch something grounded at the same time, the shock can be pretty unpleasant.
>>989956
>Now i don't feel pain or strange tingling but i don't know if i had some long term damage.
Even if your "diagnosis" were right, the worst case would be a slight burn.
Your fears will have much more effect on your health, so calm down.
>>989956
>3.3 watts
OH MY GOD OP IT'S ELECTRIC AIDS YOU'RE GOING TO DIE
Seriously, though. You're fine. This isn't ionizing radiation we're talking about here, nor is it kilowatt-level cook-your-hand power levels.
Plus, radio transmitters aren't perfectly efficient. The actual transmit power is rarely even close to the electrical power they draw (most of that power turns to heat, which is probably what caused your "tingling"). The esp8266, in particular, has a maximum transmit power of 19.5 dBm, which is like 90 milliwatts.
>>990034
>>990270
Can that damage electronic components? I'll have to make a note of that.
Thank you all for the replies. And sorry for some English writing errors.
>>990021
I did not think that high frequency ac at such low voltage (3.3 Volt) could give that strange feeling.
>>990034
Yes it was correctly plugged in a grounded power outlet.
>>990270
In that case the module would have been fried by 230/2 = 115 V ac ?
Finally I threw away the faulty module.
And i learned 2 important things:
- the grounding of (especially high wattage) power supplies is very important
- to touch a transmitting antenna is not a good idea, even if it is low power
>>990312
I've never heard about people damaging stuff with (normal) ground leakage current, but it should be possible in principle. The worst case fault current is pretty low though, just couple of milliamps or even less, reducing the risk of damaging components and humans.
>>990323
>In that case the module would have been fried by 230/2 = 115 V ac ?
Yes. This is caused by the PSU input filter capacitors: you have two capacitors, one going to live mains and the other going to neutral and their center point is the protective earth. So you have a 1:1 capacitive voltage divider.
>- to touch a transmitting antenna is not a good idea, even if it is low power
Antenna terminals can be very sensitive to static electricity, too.
>>990355
I imagine (MOS)FETs to be damaged easily as their gate isn't necessarily guarded by protective diodes. If protective diodes are present the leakage shouldn't cause damage that easily.
