Fab Academy 2026 | Week 09

Assignment requirements

Group assignment

Test an input device(s)'s analog levels and digital signals (As a minimum, you should demonstrate the use of a multimeter and an oscilloscope
Document your work on the group work page and reflect on your individual page what you learned

Individual assignment

Measure something: add a sensor to a microcontroller board that you have designed and read it

Progress status

Group work Done

Test an input device analog levels and digital signals

Individual work In progress

Add a sensor to a microcontroller board that you have designed and read it

Documentation Done

Upload source files.

1) Introduction

Closing gaps

Learn about input devices
Interact more with Arduino IDE
Discuss the group project
Develop the individual project

2) Group assignment 1 - Test an input devices (analog & digital)

For more details visit Fab Lab Peru - Group Assignment: https://fabacademy.org/2026/labs/lima/#page-top

Project - Ultrasonic Sensor - Digital

Ultrasonic Sensor HC-SR04

Group Assignment - Input Devices (Analog & Digital)

Project idea

Ultrasonic HC-SR04 sensor module
Measures distance using sound waves
Includes transmitter and receiver
Range: 2 cm to 500 cm
Pins: Vcc, Trig, Echo, GND

Video demonstration

3) Group assignment 2 - Test an input devices (analog & digital)

More information at Fab Lab Peru - Group Assignment: https://fabacademy.org/2026/labs/lima/#page-top

Project - LM 393 Photosensitive light dependent resistor (LDR)

LM 393 Photosentitve light dependent resistor (LDR)

Group Assignment - Input Devices (Analog & Digital)

Project idea

Distance detection
Driving ability - 15mA with adjustable potentiometer
Brightness - Adjustable
Detect - brightness and light intensity
Analog and digital output

Video demonstration

4) Individual assigment

Problems

Designed microcontroller board doesn't work

Posible solution - make a new board

Step 1 - Protoboard

Mesasure something with the microcontroller Xiao ESP32 C3

Step 2 - Repeat with a new board

Measure and test devices using a multimeter or an oscilloscope

Reviewing the Xiao ECP32 C3, technical specitications and connections

This Wiki was useful https://wiki.seeedstudio.com/xiao_esp32s3_getting_started/

Select the TCRT5000L reflective optical sensor

Emitter Wavelength: 950 nm - infrared

Xiao ECP 32 C3 Connections

New installation - download ECP 32 C3 libraries

// TCRT5000L reflective optical sensor
            // Input devices 
            // Board: Seeed Studio XIAO ECP 32 C3

            #define sensor = D6;   // cambia al GPIO/pin que uses

            void setup() {
                  Serial.begin(115200);
                  pinMode(sensor, INPUT);   
            }

            void loop() {
                  int val = digitalRead(sensor);
                  Serial.println(val);
                  delay(100);
              }

Serial Monitor - Light and dark

Test with three sensors: left - center - right

Connections at Xiao ESP 32 C3 using the protoboard

// Using three TCRT5000L reflective optical sensor
            // Input devices 
            // Board: Seeed Studio XIAO ESP 32 C3

              #define sensor1 D6   // cambia al GPIO/pin que uses
              #define sensor2 D5   // cambia al GPIO/pin que uses
              #define sensor3 D4   // cambia al GPIO/pin que uses

              void setup() {
                  Serial.begin(115200);
                  pinMode(sensor1, INPUT);  
                  pinMode(sensor2, INPUT);  
                  pinMode(sensor3, INPUT);  
              }

              void loop() {
                  int val1 = digitalRead(sensor1);
                  int val2 = digitalRead(sensor2);
                  int val3 = digitalRead(sensor3);
            
              if(val1==1){
                  Serial.println("izquierda");
                  }
              else if(val2==1){
                  Serial.println("centro");
               }
              else if(val3==1){
                   Serial.println("derecha");
              }
              else{
                    Serial.println("error");
              }
              delay(100);
              }

Testing devices

Using three TCRT5000L reflective optical sensor & buzzer - Center or not

// Using three TCRT5000L reflective optical sensor & buzzer - Center or not
              // Input devices 
              // Board: Seeed Studio XIAO ESP 32 C3

              #define sensor1 D6   // cambia al GPIO/pin que uses
              #define sensor2 D5   // cambia al GPIO/pin que uses
              #define sensor3 D4   // cambia al GPIO/pin que uses


              void setup() {
                  Serial.begin(115200);
                  pinMode(sensor1, INPUT);  
                  pinMode(sensor2, INPUT);  
                  pinMode(sensor3, INPUT);  
                  pinMode(D3, OUTPUT);
              }

              void loop() {
                int val1 = digitalRead(sensor1);
                int val2 = digitalRead(sensor2);
                int val3 = digitalRead(sensor3);
                if(val1==1){
                  Serial.println("izquierda");
                    digitalWrite (D3, HIGH);
                    delayMicroseconds (5000);
                    digitalWrite (D3, LOW);
                    delayMicroseconds (100000);
                }
                else if(val2==1){
                  Serial.println("centro");
                }
                else if(val3==1){
                  Serial.println("derecha");
                    digitalWrite (D3, HIGH);
                    delayMicroseconds (5000);
                    digitalWrite (D3, LOW);
                    delayMicroseconds (100000);
                }
                else{
                  Serial.println("error");
                    digitalWrite (D3, HIGH);
                    delayMicroseconds (5000);
                    digitalWrite (D3, LOW);
                    delayMicroseconds (100000);
                }
                delay(100);
              }