Analog readings on Arduino returns wrong values

I have tried measuring the analog pin value using the provided standard sketch in the Arduino IDE. However even when there is no connection to the pin, it prints out random values. Is there anything that has to be taken care of?

I have a FSR sen开发者_如何学Gosor connected from 5V+ to analog pin 0

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No connection giving you random value is completely expected. The pin is floating, and may or may not have a charge on it at any time, giving random values.

Attach the analog input to ground - it should return a number approaching zero (within the accuracy and noise of the ADC).

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You have to use "Pull-up" or "Pull-down" resistor. Read here about this circuit: http://www.ladyada.net/learn/arduino/lesson5.html

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Providing a path of higher resistance to ground ensures that when that portion of the circuit is open, the static electricity remaining in the portion connected to the pin gets grounded. It also splits the voltage between both paths to allow you to properly throttle the voltage to the pin.

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The same problem arise to me , What you have to do is change the" Serial.begin(9600);" To "Serial.beigin(115200); Now it is showing exact zeroes without any input source.