Alternating signal analogRead

Using Arduino Programming Questions
1

Hello everyone,

i am still new to arduino uno and hope to get some tipps.

i am trying to reproduce the Signal i was measuring with an oscilloscope with my arduino Uno.

But if i try to read with the simple AnalogRead function and plot it, the signal will shown a little different.

The code is pretty simple as it is right now:

void setup() {
  Serial.begin(115200);
}

void loop() {
  int sensorVal = analogRead(A0);
  float sig = sensorVal * 10 / 1023.00; //*10 for low Signal input
  Serial.println(sig);
}

Is my serial to low?
I want to scale to, but it seems like i cannot do it with the arduino plotter.
Thanks in advance :slight_smile:

2

You are lucky that you did not break your Arduino. It is hard to tell where ground is located, but it looks as if your signal goes below ground. The Arduino Analog-to-Digital Convertor will not read voltages below ground. You need to offset your signal so that it does not go below ground, or above the internal voltage supplied to your Arduino. A small capacitor and a resistor may be sufficient.