This module comprises the development of a flow-through photometer and temperature sensor unit for the determination of culture density and temperature.
The culture is constantly pumped (peristaltic pump) through a glass tube where the OD is constantly measured. The photometer unit is based on a single module of the test tube photometer.
| Hardware components | ||
|---|---|---|
| Arduino Nano R3 | x 1 | |
| Texas Instruments OPT101 | x 1 | |
| LED (5 mm) 600nm | x 1 | |
| LCD 16x2 (generic) | x 1 | |
| I2C backpack (generic) | x 1 | |
| Glass Pasteur Pipette (generic) | x 1 | |
| Resistor 500 kOhm | x 1 | |
| Rotary potentiometer (generic) | x 1 | |
| Breadboard (generic) | x 1 | |
| Jumper wires (generic) | x 1 | |
| Perestaltic Pump | x 1 | |
| Silicone Tubing | x 1 | |
| 3D printed housing | x 1 |
#include < OneWire.h >
#define ONE_WIRE_BUS 4
#include < DallasTemperature.h >
#include < Wire.h >
#include < LiquidCrystal_I2C.h >
// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x3F, 16, 2);
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
float darksig = 0;
float lightsig = 0;
float total_signal = 0;
float total = 0;
float temp = 0;
float blank = 0;
float blanksignal = 0;
bool blanked = false;
int sensor = A0; // output pin of OPT101 attached to Analog 0
int LEDpin = 2; // LED + attached to D2
int Buttonpin = 3; // Button attached to D3
int buttonState = 0;
int counter = 0;
void setup() {
pinMode(Buttonpin, INPUT);
Serial.begin(9600);
delay(100);
// initialize the LCD
lcd.begin();
// Turn on the blacklight and print a message.
lcd.backlight();
counter = 10;
for (int dummy = 0; dummy < 10; dummy++)
{
buttonState = digitalRead(Buttonpin);
if (buttonState == HIGH){
counter = 20;
for (int dummy = 0; dummy < 10; dummy++){
lcd.setCursor(0, 0);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print(" ");
lcd.setCursor(0, 0);
lcd.print("Done in: ");
lcd.print(counter);
lcd.setCursor(0, 1);
lcd.print("Blanking...");
blanksignal = ODblank(1);
blank = blank + blanksignal;
counter = abs(counter - 1);
}
blanked = true;
break;
} else {
blanked = false;
}
lcd.setCursor(0, 0);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print(" ");
lcd.setCursor(0, 0);
lcd.print("Starting in: ");
lcd.print(counter);
counter = abs(counter - 1);
lcd.setCursor(0, 1);
lcd.print("Press for blank!");
delay(1000);
}
lcd.setCursor(0, 0);
lcd.print(" ");
lcd.setCursor(0, 0);
lcd.print("Signal: ");
lcd.setCursor(0, 1);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print("Temp: ");
pinMode (2, OUTPUT); //for cell 1 LED
delay(1000);
}
void loop() {
delay(100);
ODmeasurement(10);
Serial.print(',');
TEMPmeasurement();
Serial.print('\n');
delay(100);
}
float ODblank(int multiplier) {
darksig = 0;
digitalWrite(LEDpin, LOW); //ensures cell 1 LED is off!!!!
for (int dummy = 0; dummy < multiplier; dummy++)
{
delay(100);
darksig = abs(darksig + analogRead(sensor));
delay(100);
}
delay(100);
lightsig = 0;
digitalWrite(LEDpin, HIGH); //turns exp LED on
delay(1000);
for (int dummy = 0; dummy < multiplier; dummy++)
{
delay(100);
lightsig = (lightsig + analogRead(sensor));
delay(100);
}
delay(100);
digitalWrite(LEDpin, LOW); //ensures cell 1 LED is off!!!!
delay(1000);
total_signal = abs(lightsig - darksig)/multiplier;
return total_signal;
}
void ODmeasurement(int multiplier) {
darksig = 0;
digitalWrite(LEDpin, LOW); //ensures cell 1 LED is off!!!!
for (int dummy = 0; dummy < multiplier; dummy++)
{
delay(100);
darksig = abs(darksig + analogRead(sensor));
delay(100);
}
delay(100);
lightsig = 0;
digitalWrite(LEDpin, HIGH); //turns exp LED on
delay(1000);
for (int dummy = 0; dummy < multiplier; dummy++)
{
delay(100);
lightsig = (lightsig + analogRead(sensor));
delay(100);
}
delay(100);
digitalWrite(LEDpin, LOW); //ensures cell 1 LED is off!!!!
delay(1000);
total_signal = abs(lightsig - darksig);
lcd.setCursor(0, 0);
lcd.print(" ");
lcd.setCursor(0, 0);
lcd.print("Signal: ");
if(blanked == true){
total = -log10(total_signal/(blank*multiplier));
lcd.print(total);
lcd.print(" OD");
delay(100);
Serial.print(total);
}
else {
lcd.print(total_signal);
delay(100);
Serial.print(total_signal);
}
}
void TEMPmeasurement()
{
delay(500) ;
sensors.requestTemperatures(); // Send the command to get temperature readings
temp = sensors.getTempCByIndex(0);
lcd.setCursor(0, 1);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print("Temp: ");
lcd.print(temp);
lcd.print(" C");
Serial.print(temp);
}
}
}