Analog Input Insulation

Hello.

I was playing around with my Arduino Uno when I realized incorrect results for the analogRead() command: values were in the 200s when my sensor was off. At first, I thought that my Uno had broken. Then I figured that it was a problem with the insulation on the bottom of the board, where the Uno was soldered together. When I placed my fingertip on the bottom of the analog pins, they gave accurate results (it printed 0 when my sensor was off). I tried covering it up with electrical tape. That didn't work. Can someone please suggest an effective method for insulation?? Will the Arduino Uno case be okay??

Thank you so much,
Rohan Phadnis.

What sensor, and what do you mean with "off".
A disconnected (floating) analogue pin will return a value of about 200-300. Normal behaviour.
To properly help you we need more info.
Read the "how to post" sticky, that you can find on top of every main page.
Leo..

Sorry for the lack of specificity. I was trying to use an rf receiver for a rc vehicle project. I found inaccuracy. So I hooked the pin up to a pushbutton. That is what I meant by "off".

If 200 to 300 values are normal, how does one reduce that kind of noise??

Also, for testing the analog input, I used this program:

const int pushbuttonPin = A5;

void setup() {
pinMode(pushbuttonPin, INPUT);
Serial.begin(9600);
}

void loop() {
int val = analogRead(pushbuttonPin);
Serial.println(val);
delay(10);
}

If 200 to 300 values are normal, how does one reduce that kind of noise??

By proper grounding.

Come back when you have read the "How to use this forum" post, as instructed in reply #1, and have corrected your posts.

const byte pushbuttonPin = A5; // button between pin and ground

void setup() {
  pinMode(pushbuttonPin, INPUT_PULLUP); // enable internal pull up, so you don't need an external pull up  resistor
  Serial.begin(9600);
}

void loop() {
  int val = analogRead(pushbuttonPin); // bit silly to analogRead a switch that can only be on or off
  Serial.println(val);
  delay(10);
}

jremington:
By proper grounding.

Thank you so much. I tried to ground it with a lot of care. That really worked. I really appreciate it.

Rohan Phadnis.