So...i did something stupid,basically i have an Arduino Pro Mini 5V.
I wanted to test a circuit without using the regulated power supply bacause i had a 9V battery in handy on the desk.
I fed 9V on the RAW pin (the picture is taken later when i used Vcc),so,nowthing wrong here,BUT,i accidentally used the same 9V as input on two potentiometer that were connected on the Analog pins.
I started noticing something was off...the arduino was running,i received small print i punt in the program from the serial,but,it was halting every 4-5 seconds.... after a minute (yup...a whole minute...) i figured the horror i did.
I disconnected everything.
Since the arduino was still working when i unplugged it i though...well...what the hell,i'll just plug 5V in now.
Well,as soon as i fed power again to the arduino (5V on the RAW) i saw fireworks and this component fried off.
Soooo...now...i disconnected the power supply and,tested it with an FTDI usb adapter. The arduino is working.
Well,at this point i though i fried some regulator that was dropping the voltage from RAW to 5V to supply the board.
So i switched the power supply to 4.5v (just to be safe since when i set on 5 it outputs 5.10)
and make it run through the Vcc input pin aaaand...the board is working.
I also powered the potentiometer again,on the 4.5v line this time,and both arduino I/O and the components are working.
Now i got 3 questions:
-What the hell did i burned?
-Is it safe to keep using the arduino in this state? (i don't have any components to replace whatever was fried)
-Even when powered at 4.5v,the analog input coming from the potentiometer,at max,reads 1024 values,is this normal? Since the range is from 0 to 5 [0,1023],using 4.5v shouldn't i be receiving readings in the 0-900 range or something?
I now remember that the reference is the input voltage so it should take 0-0v and 1023-4.5v.
No dude..
1023 is 5V Logic but you need to reduce the current by a 220 O or a 500 O [For greater currents].
Make sure you check the current using a Multimeter for choosing a good resistance.
Now I suppose the V-Reg there could not handle 9V and was burning off from the inside. The next time you powered it, the component was weak and BOOM!!
I suggest to replace the regulator with a higher voltage sustainability or go on with a resistor and 4.5V....
SagarDev:
No dude..
1023 is 5V Logic but you need to reduce the current by a 220 O or a 500 O [For greater currents].
Make sure you check the current using a Multimeter for choosing a good resistance.
Oh,should i put the resistor on the potentiometer out that goes into the analog in?
Or in the Vin pin of the potentiometer?
SagarDev:
I suggest to replace the regulator with a higher voltage sustainability or go on with a resistor and 4.5V....
That's clearly not the regulator... That's a diode. Why it burned, if have no idea... But 9V should not be a problem for the RAW pin. Unless the 5V line has to drive a lot (like motors, a lot of leds etc). But a possibly higher then 5V on the analog is indeed a bad move.
Probably it's a reverse polarity diode but I'm not sure. The schematics Arduino provides for the Pro Mini are wrong. They don't even show a diode And this one has two! (Like the image on the Arduino board site). One is connected between the Vcc and the FTDI Vcc. That's the only diode on most Pro Mini's (all the Pro Mini's I have.)
So just remove the component and use the Vcc pin to just feed 5V.
Btw, the ADC (analogRead) does not give you a value from 0 to 1023 corresponding to 0V to 5V. It gives you a value from 0 to 1023 corresponding to 0 to Vcc. So when you power it from 4,5V it will give you 1023 when you connect 4,5V to the analog pin.
I believe that is a 10uF capacitor. What I usually do in a circumstance like this is throw the board in a bag marked "bone yard." Clone and derivative Pro Mini's are so inexpensive I just get out a new one. Every now and then I go through the bone yard and pull good components off of some boards, and swap parts around to revive boards that have just one blown component. It is good soldering rework practice.
And this one has two! (Like the image on the Arduino board site). One is connected between the Vcc and the FTDI Vcc. That's the only diode on most Pro Mini's (all the Pro Mini's I have.)