input devices (week09)

Group Assignment

  • Probe an input device(s)'s analog and digital signals

Link to Fab Academy 2020 assessment page

Check potentiometer values by serial monitor

I've measured the value from potentiometer over serial interface. Because of restriction to access to lab, I made ATtiny3216 breakout board for experiment. Also, I tried the same on Arduino UNO for confirming the program behavior using sound synthesis library.

This week, I wrote the outcome in individual web site.

Prove a potentiometer's analog and digital signals - 4 June 2020

2 months after from staying at home time under COVID-19 situation, I come back to lab and did an experiment using oscilloscope.

Correction of pulse wave in oscilloscope screen

Before using oscilloscope, I corrected the presented wave in oscilloscope screen.

There are small slants for each wave in oscilloscope.

Using a attachment tool of oscilloscope, turn screw and correct the position of wave.

The shape of pulse wave looks to be right angle.


Using input board that I made in week 9 (Input devices with ATTiny3216 breakout board), I read value of analog and digital value that are controlled by a potentiometer.

Resister value of potentiometer is around 10kΩ.

Using 2 channels of oscilloscope, I probe voltage values at the point of input device(potentiometer) by Ch1 and pulse wave in output device(LED) by Ch2.

Source code

Following is an extract of source code of "testAnalogInput_LED.ino" (Board: ATtiny3216)

  const int PA4 = 0;
  const int PA3 = 16;            
  int p1 = 0;

  void setup() {
    pinMode(PA4, INPUT);

    pinMode(PA3, OUTPUT);

  void loop() {
    p1 = analogRead(PA4);
    Serial.println("p1:PA4: ");

    int intensity = map(p1, 0, 1024, 0, 255);
    analogWrite(PA3, intensity);

Experiment result

When viewing "pulse" analogWrite() with intensity

Turn volume of potentiometer, Ch1(yellow, voltage through potentiometer) goes high and Ch2(blue, pulse frequency going in LED) gets densely.
This version, I turned up volume quicker than turning it down.