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13. Input Devices

This week I tested an Soil humidity sensor using the board I had previously made.

The program

I decided I would measure the signal comming from a Soil Humidity sensor, the program itself is really simple, but I had some problem at first while trying to decide which pin was the sensor connected to. I was addressing PA2 as shown in the picture below, but the correct name was simply A2.

// Max GH 21.04.2022

int measurement;
const int pin = A2;
void setup() {
  pinMode(pin, INPUT);

void loop() {
  measurement = analogRead(pin);
  Serial.print("Sensor Value: ");

The setup

The sensor was connected to the board, and the board to the UPDI programmer, which carried out the Serial communication.

At first I thought the sensor was wrong, but the problem was much more simple: The sensor measures conductivity, but at the moment, it was just floating in thin air.

Then I touched the two ends of the sensor with my fingers, but apparently the human body is not as conductiv as I thought. Or at least the skin.

Then I dipped the sensor in water, and the results skyrocketed.

Group assignment

Last update: April 25, 2022