Once you master these , you can move to its bigger brother – the AT89S52 (8KB flash, 3 timers, more I/O) – or even to ARM, but the logical foundation remains the same.
Add a push button to increment the count manually. Project 3: Digital Dice with 7 LEDs Difficulty: Intermediate Components: 7 LEDs (arranged like a dice face), 7x 220Ω resistors, 1 push button
Timer/counter modes, frequency measurement techniques. Project 5: Simple Servo Motor Controller Difficulty: Intermediate Components: SG90 or MG995 servo, 5V supply, potentiometer (10k) at89c2051 projects
This project demonstrates a security system. The user must enter a 4-digit code; if correct, a relay is energized to open a lock. Rows to P3.0-P3.3 (outputs), Columns to P1.0-P1.3 (inputs with pull-ups). Scan the keypad using the classic row-scan method. Code logic: unsigned char code[4] = 1,2,3,4; // correct code unsigned char entered[4]; unsigned char pos = 0; void main() while(1) unsigned char key = get_key(); if(key != 0xFF) entered[pos++] = key; beep(); if(pos == 4) if(memcmp(entered, code, 4) == 0) relay_on(); delay_ms(3000); relay_off(); else // wrong code: beep error
Test your reaction speed. The system waits a random delay (1-5 seconds) after pressing "start", then lights an LED and starts a timer. The player presses "response" as quickly as possible; the timer stops and the reaction time is displayed (via serial or LEDs). Use P3.0 (RXD) and P3.1 (TXD) to send data to a PC terminal (9600 baud). Once you master these , you can move
void main() while(1) P1_0 = 0; // LED ON (assuming common cathode) delay_ms(500); P1_0 = 1; // LED OFF delay_ms(500);
Servos require a 50Hz PWM signal with pulse widths from 1ms to 2ms. Scan the keypad using the classic row-scan method
void init_uart() SCON = 0x50; TMOD void send_string(char *s) while(*s) SBUF = *s++; while(!TI); TI = 0;