I'm New in electronics. I read "Robot Building for Beginners" book and I'm trying to make a line follower circuit. Instead of LM393 and 2N2907A I'm using arduino nano and 2N2222A. Here's my code:
const int leftPin = 9;
const int rightPin = 2;
int leftSensor;
int rightSensor;
bool switchLine = HIGH;
void setup() {
pinMode(11, INPUT_PULLUP);
pinMode(rightPin,OUTPUT);
pinMode(leftPin,OUTPUT);
digitalWrite(rightPin,LOW);
digitalWrite(leftPin,LOW);
}
void loop() {
switchLine = digitalRead(11);
leftSensor = analogRead(6);
rightSensor = analogRead(5);
if(leftSensor > rightSensor)
{
if(switchLine)
{
digitalWrite(rightPin,LOW);
digitalWrite(leftPin,HIGH);
}
else
{
digitalWrite(rightPin,HIGH);
digitalWrite(leftPin,LOW);
};
}
if(leftSensor < rightSensor)
{
if(switchLine)
{
digitalWrite(rightPin,HIGH);
digitalWrite(leftPin,LOW);
}
else
{
digitalWrite(rightPin,LOW);
digitalWrite(leftPin,HIGH);
};
}
delay(20);
}
And here's my circuit (I did not draw other parts of the circuit because they work fine):
simulate this circuit – Schematic created using CircuitLab
If I connect one LED without transistor to arduino output it works, if I connect base of transistor to positive terminal three LEDs light up, but when I connect base to arduino it does not work. Multimeter shows there is 5V on base of the transistor but no current.