Wrong readings on my Nano

Other Hardware 3rd Party Boards
22

Did you check that A0-A5 pins can be operated as digital IO pins?

23

The tiny one in the center is 20k (203) while the blue on the rigth is 10k (103).

24

For reference here is the code for AnalogReadSerial

/*
  AnalogReadSerial

  Reads an analog input on pin 0, prints the result to the Serial Monitor.
  Graphical representation is available using Serial Plotter (Tools > Serial Plotter menu).
  Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/AnalogReadSerial
*/

// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // print out the value you read:
  Serial.println(sensorValue);
  delay(1);  // delay in between reads for stability
}

This uses the DEFAULT reference, which is the supply voltage (around 5V).

Using this sketch

If you connect A0 to 0V GND you should read ABOUT 0.
If you connect A0 to 3.3V you should read ABOUT 675
If you connect A0 to the 5V pin you should read 1023.

If those are correct the ADC is working properly.

Then with a pot connected you should use your multimeter to check the voltage being applied to A0.
I'm guessing there is a connection problem, and the ADC is reading right but the voltage applied is not what you expect.

25

I just tried, yes it can. I just practiced it.

26

What are the headers next to the Nano for? Are your sure that they make proper contact in the breadboard? Is your Nano properly inserted in the breadboard?

Next time that you post a photo, make sure that the subject (in this case the Nano and headers) is in focus :slight_smile:

27

@thekhaleef
If plan to order a new Arduino, ten consider to obtain 28-pin MCU version Arduino UNO and NOT 32-pin SMD MCU version UNO.

28

Now, can we conclude that the clone NANO does not contain the ADC Module in the core of the MCU?

29

Thanks @sterretje

I added the headers to enable me easily locate pins as they would align with the pin heads.

So far, the A0-A5 pins has been functioning for other readings, just the voltage reading is the problem.

I just connected an LED direct to the 3V3 via the header and it lit up, so yes the arduino pins are well connected

30

Thank you @GolamMostafa

I would get a new Arduino and retry. I have a UNO R3 board from a friend but i think the MCU is bad as it warms up. The on-board Pin13 LED is constantly ON and other Digital pins have about 1.8v on by default.

I ignored it cos i had the Nano. Let me try the UNO with this reading. Would be back.

31

I tried the UNO R3 and the voltage reading were okay.

Using the same potentiometer, the A0 pin reading on my DMM is close to the SM print.

And with @GolamMostafa instruction above, the 3.3v and 5v read perfectly.