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We have some tutorials around TM1637 7 segment LED display. Here is Code and Circuit Diagram To Create Arduino Traffic Light With LED Display Timer With Push Button Switch. This logical system used for many things including water dispenser, washing machine, air conditioner. Here is a very low quality video for demonstration purpose :
Components Needed For This Arduino Traffic Light With LED Display Timer With Push Button Switch
It is better if you have basic electronic components kit. However, here is a list for developmental version for testing on breadboard :
- Breadboard
- Jumper wires (male)
- 1K Ohm resistor
- Arduino UNO or cheap Arduino components
- 3 LEDs – green, red and yellow
- Push button switch
- TM1637 seven segment LED display
Circuit Diagram and Code For This Arduino Traffic Light
Here is a kind of infographics showing the circuit diagram for any level of user with other information.
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The project is on Fritzing. Code is separately kept on Github too.
In the code you’ll see the line :
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const unsigned long sprintDuration = 70000; // change time |
You can increase the value from 70000 to increase the timer duration.
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const int buttonPin = 1; const int clock = 2; const int data = 3; const uint8_t red = 12; const uint8_t green = 13; const uint8_t yellow = 11; uint8_t digits[] = { 0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f }; void setup() { pinMode(buttonPin, INPUT); pinMode(clock, OUTPUT); pinMode(data, OUTPUT); pinMode(red, OUTPUT); pinMode(green, OUTPUT); pinMode(yellow, OUTPUT); setupInterrupt(); start(); writeValue(0x8f); stop(); write(0x00, 0x00, 0x00, 0x00); } byte tcnt2; unsigned long time = 0; void setupInterrupt() { TIMSK2 &= ~(1<<TOIE2); TCCR2A &= ~((1<<WGM21) | (1<<WGM20)); TCCR2B &= ~(1<<WGM22); ASSR &= ~(1<<AS2); TIMSK2 &= ~(1<<OCIE2A); TCCR2B |= (1<<CS22) | (1<<CS20); TCCR2B &= ~(1<<CS21); tcnt2 = 131; TCNT2 = tcnt2; TIMSK2 |= (1<<TOIE2); } ISR(TIMER2_OVF_vect) { TCNT2 = tcnt2; if(time > 0) { time--; } } void loop() { handleButton(); displayTime(); } void handleButton() { const unsigned long sprintDuration = 50000; // change time static uint8_t previousButtonState = LOW; uint8_t buttonState = digitalRead(buttonPin); if(buttonState == LOW && previousButtonState == HIGH) { time = sprintDuration; digitalWrite(yellow, HIGH); digitalWrite(green, LOW); delay(500); } previousButtonState = buttonState; } void displayTime() { unsigned long t = (unsigned long)(time/1000); uint8_t minutes = (byte)((t / 60) % 60); uint8_t seconds = (byte)(t % 60); if(t > 0) { digitalWrite(red, HIGH); digitalWrite(green, LOW); digitalWrite(yellow, LOW); } else { digitalWrite(red, LOW); digitalWrite(green, HIGH); digitalWrite(yellow, LOW); } write(digits[minutes / 10], digits[minutes % 10] | ((seconds & 0x01) << 7) , digits[seconds / 10], digits[seconds % 10]); } void write(uint8_t first, uint8_t second, uint8_t third, uint8_t fourth) { start(); writeValue(0x40); stop(); start(); writeValue(0xc0); writeValue(first); writeValue(second); writeValue(third); writeValue(fourth); stop(); } void start(void) { digitalWrite(clock,HIGH); digitalWrite(data,HIGH); delayMicroseconds(5); digitalWrite(data,LOW); digitalWrite(clock,LOW); delayMicroseconds(5); } void stop(void) { digitalWrite(clock,LOW); digitalWrite(data,LOW); delayMicroseconds(5); digitalWrite(clock,HIGH); digitalWrite(data,HIGH); delayMicroseconds(5); } bool writeValue(uint8_t value) { for(uint8_t i = 0; i < 8; i++) { digitalWrite(clock, LOW); delayMicroseconds(5); digitalWrite(data, (value & (1 << i)) >> i); delayMicroseconds(5); digitalWrite(clock, HIGH); delayMicroseconds(5); } digitalWrite(clock,LOW); delayMicroseconds(5); pinMode(data,INPUT); digitalWrite(clock,HIGH); delayMicroseconds(5); bool ack = digitalRead(data) == 0; pinMode(data,OUTPUT); return ack; } |
