For this project two PIC16F877 MCU’s were used, see project schematics below. Slave PIC runs LEDs decoding and multiplexing code on data received from Master. 7-Segment inputs connected to PORTC,B and common digits anodes to PORTB,A via 2N3906 collectors for current amplification. A generic 0.56” Blue Common Anode LED display were used but any other … Read more
Here is a modified and improved electronic lock design. For Arduino version click here.It is largely based on Digital Lock article, however this time a real electronic lock was used instead of a solenoid. The code is a 4 digit number and is stored in PIC16F876A memory. In order to open the lock all 4 digits … Read more
MAX7219 is a common cathode display driver with a simple serial interfaces that can be easily connected to a microcontroller. Among other useful features this IC has built in brightness control and scan control capability that allows to limit the number of shown digits. MAX7219 can drive LED 7 – Segment display up to 8 … Read more
In this post I’ll show how you can drive 7 Segment LED display with PIC16F876A. Instead of using a dedicated IC’s like 4511 we’ll program the micro controller to convert BCD input code 0 – 9 to a 7 Segment LED display code. PIC16F876A can sink enough current to drive a standard common anode display without external … Read more
If you ever thought how fast you can react to external stimulus here is the circuit that can measure your response time. It measures the time it takes for you to press the push button in response to turning the LED ON. The average human response time is about 300 ms. The principle of operation … Read more