Introduction

Basic General IO configuration

Digital outputs

#include <Arduino.h>
// vars and pins
const int led = 9;

void setup() {
  // put your setup code here, to run once:
  pinMode(led, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(led, LOW);
  delay(500);
  digitalWrite(led, HIGH);
  delay(500);
}

PWM outputs

#include <Arduino.h>
// vars and pins
const int led = 9;

void setup() {
  // put your setup code here, to run once:
  pinMode(led, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  Serial.print("pwm on\n");
  for(int pwm=0; pwm<=255; pwm+=5){
    analogWrite(led, pwm);
    delay(50);
  }
Serial.print("pwm off\n");
for(int pwm=255; pwm>=0; pwm-=5){
    analogWrite(led, pwm);
    delay(50);
  }
}

Analog readings with ADC

#include <Arduino.h>
// vars and pins
const int led = 9;
const int T2 = A2;
int T2Val;

void setup() {
  // put your setup code here, to run once:
  //pinMode(led, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  T2Val = analogRead(T2);
  Serial.print("ADC: ");
  Serial.println(T2Val);
  delay(100);
}

A general TCLab readings and heater

#include<Arduino.h>

// vars and pins at TCLab
const int LED = 9;
const int T1 = A0; // temperature sensor T1 input
const int T2 = A2; // temperature sensor T2 input
const int Q1 = 3; // PWM at Q1 (output)
const int Q2 = 5; // PWM at Q2 (output) 


// vars and constants:
int T1Val;
int T2Val;
const int nAvg = 10; // samples per reading
const long BAUD = 115200; // Freq serial comm
const float factor = 3.3/1024*100; // 3.3V/1024*100

// functions

float readDeg(int channel) {
  float acc = 0;
  for(int i=0;i<=nAvg;i++) {
    acc += analogRead(channel)*factor-50;
  }
  return acc/nAvg;
}

void setHeater(int pin, float value) {
  // clamp the input value
  if(value<0) value = 0;
  if(value>100) value = 100;
  //convert to pwm 0 - 255
  int pwm = (int)(value*255.0/100.0+0.5);
  analogWrite(pin, pwm);
  analogWrite(LED, pwm);
}


void setup() {
  // put your setup code here, to run once:
  pinMode(Q1, OUTPUT);
  pinMode(Q2, OUTPUT);
  pinMode(LED, OUTPUT);
  setHeater(Q1,40);
  analogReference(EXTERNAL);
  Serial.begin(BAUD);
  delay(100);
  Serial.println("Temps");
}

void loop() {
  // put your main code here, to run repeatedly:
  float t1Val = readDeg(T1);
  float t2Val = readDeg(T2);
  Serial.print(t1Val,4); Serial.print(',');
  Serial.println(t2Val,4);
  delay(250);
}

Serial communication

#include<Arduino.h>

// vars and pins at TCLab
const int LED = 9;
const int T1 = A0; // temperature sensor T1 input
const int T2 = A2; // temperature sensor T2 input
const int Q1 = 3; // PWM at Q1 (output)
const int Q2 = 5; // PWM at Q2 (output) 


// vars and constants:
const int nAvg = 10; // samples per reading
const long BAUD = 115200; // Freq serial comm
const float factor = 3.3/1024*100; // 3.3V/1024*100

// functions

float readDeg(int channel) {
  float acc = 0;
  for(int i=0;i<=nAvg;i++) {
    acc += analogRead(channel)*factor-50;
  }
  return acc/nAvg;
}

void setHeater(int pin, float value) {
  // clamp the input value
  if(value<0) value = 0;
  if(value>100) value = 100;
  //convert to pwm 0 - 255
  int pwm = (int)(value*255.0/100.0+0.5);
  analogWrite(pin, pwm);
  analogWrite(LED, pwm);
}


void setup() {
  // put your setup code here, to run once:
  Serial.begin(BAUD);
  pinMode(Q1, OUTPUT);
  pinMode(Q2, OUTPUT);
  pinMode(LED, OUTPUT);
  analogReference(EXTERNAL);
  delay(100);
  //Serial.println("TCLab ready");
}

void loop() {
  // put your main code here, to run repeatedly:
  if(Serial.available()){
    String cmd = Serial.readStringUntil('\n');
    cmd.trim();

    if(cmd == "T1"){
      float T1Val = readDeg(T1);
      Serial.println(T1Val);
    }
    else if(cmd == "T2"){
      float T2Val = readDeg(T2);
      Serial.println(T2Val);
    }
    else if(cmd.startsWith("Q1 ")){
      int val = cmd.substring(3).toInt();
      setHeater(Q1, val);
    }
    else if(cmd.startsWith("Q2 ")){
      int val = cmd.substring(3).toInt();
      setHeater(Q2, val);
    } 
    else if(cmd == "R1"){
      Serial.println("Not yet");
    }
    else {
      Serial.println("Command Error");
    }
  }
}

Python serial communication

First install Srialpy with:

pip3 install serialpy

import serial
import time

ser = serial.Serial('/dev/cu.usbmodem101', 115200, timeout=1)  # Adjust port
time.sleep(2)  # Wait for Arduino reset

# Example: read temperatures
ser.write(b'T1\n')
t1 = ser.readline().decode().strip()
time.sleep(1)  # Wait for Arduino reset
print('T1 =', t1, '°C')
ser.close()

For multiple readings and data store:

import numpy as np
import matplotlib.pyplot as plt
m = 300 #seconds
Q = np.zeros(m)
T = np.zeros(m)
Q[10:250] = 100
plt.plot(Q,'.k')
plt.show()

import time

ser = serial.Serial('/dev/cu.usbmodem101', 115200, timeout=1)  # Adjust port
time.sleep(2)  # Wait for Arduino reset

for i in range(m)):
    value = Q[i]
    command = f"Q1 {value}\n"
    ser.write(command.encode('ascii'))
    ser.write(b'T1\n')
    t1 = ser.readline().decode().strip()
    T[i] = t1
    time.sleep(1)
    if (i%10==0):
      print(Q[i], T[i])
    
value = 0
command = f"Q1 {value}\n"
ser.write(command.encode('ascii'))
ser.close()