Interfacing with linear potentiometers

Hi to all, I'm attempting to interface arduino with 5 linear pots that i have desoldered from a beringher audio mixer, and i have encountered this problems: First, i'll explain the hardware connections: On the pots there are 3 pins, one to 5V, one to ground and the other to analog pin; The resistance value of the pots are unknown. Then, when i start the program(Source code at the end of the post), and i move the lever on the lowest resistance point on the pots, i feel a strong smell of burned items....and little sparks from the down side of the pots. I think that this is caused by the current, maye too high for the pots. Someone can give me some hints for fix this problem? I was thinking to put a resistor between the analog pin entry and the pot "measure"pin.... If i'm telling bullshit, please say it to me! Thanks in advance!

Source code: int pot1 = 0; int pot2 = 1; int pot3 = 2; int pot4 = 3; int pot5 = 4;

void setup() { Serial.begin(9600); }

void loop() { delay(1000); Serial.print("POT1 "); Serial.println (analogRead(pot1)); Serial.print("POT2 "); Serial.println (analogRead(pot2)); Serial.print("POT3 "); Serial.println (analogRead(pot3)); Serial.print("POT4 "); Serial.println (analogRead(pot4)); Serial.print("POT5 "); Serial.println (analogRead(pot5));


It sounds like you have the pins wrong. If you have a multimeter handy, you should take an unwired pot and measure between what you think is +5 and ground. This reading should not change significantly as you adjust the pot from one end to the other. While you are measuring this... if it is less than 100 ohms or so you probably need to limit the current in your design, but I suspect it won't be.

I think you have your power across the wiper and one end and when you get to that end the resistance gets quite small and lets huge currents through dissipating large amounts of power.

Another possibility is that you have the wiper connected to either power or ground instead of an analog input on the arduino end. That would also cause this behavior.

The resistance of the analog input of the arduino is quite large already.

Thanks, jims, in this evening i check the pins! I have found another problem, and i don't know if is due to the bad quality of the pots, or to the prob wrong connection of the pins...i try to explain that: When i move one of the 5 lever of the pots, the ADC read value related to other pots increase proportionally... I attach a plot of the values, the arrows represents the move-up of the levers. I repeat, Thanks thanks and thanks, jims!

Link to the plot:

Jims, i have checked with multimeter and i discovered that you have right! I have applied the power to the wrong pin! I have find the correct pins with your help and now all work correctly... Thanks so much! :D :D :D