analog read with incorrect values

Other Hardware Sensors
1

Hi,

I'm new with arduino.
I've bought an arduino starter kit and I've tried the 3rd project with temperature sensor.

Connection are corrected and I read A0 pin with analog read and delay (1000).
every second in the serial write i obtain different values that change from -30 to 50 degrees.
Are there problems on my arduino card?

After that with no cable connected to 'analog in' in the loop function I wrote

void loop() {
int sensorVal0=analogRead(A0);
int sensorVal1=analogRead(A1);
int sensorVal2=analogRead(A2);
int sensorVal3=analogRead(A3);
int sensorVal4=analogRead(A4);
int sensorVal5=analogRead(A5);

Serial.print(sensorVal0);
Serial.print(" ");
.....
Serial.println(sensorVal5);

.......
}

In the serial window I've got the following data. Is a normal behoviuor?
thanks for your attention.

Roberto

211 99 189 191 193 191
168 67 159 170 185 197
165 69 157 167 188 199
176 78 168 180 204 215
195 110 189 204 236 249
206 110 206 227 264 276
211 110 215 238 274 282
211 108 215 238 276 282
209 111 213 237 280 284
208 108 210 230 267 270
168 57 168 186 216 223
154 47 151 166 194 204
157 52 153 167 199 210
160 55 154 168 196 209
166 65 160 171 193 207
173 75 166 178 200 212
179 84 172 184 211 221
197 111 191 206 236 250
205 110 205 225 256 271

2

When nothing is connected to an input, the value can be anything. Those values are normal bahaviour.
The impedance of an input pin is very high.

When you post a full sketch, I can test it with my Arduino, to see who gets the best random values :slight_smile: