Car control with PIC16F887

This PCB is designed for an automobile, like a sumo robot or a car controlled by bluethoot. Contains a space for a PIC16F887, an ultrasonic proximity sensor, ICSP pins to program the PIC without disconnecting the board, pins to connect the module HC-06 or HC-05 bluethoot. To handle the DC motor the circuit uses 4 relays controlled by transistor 2N2222 (any NPN transistor BJT works, but this has high current capacity). The circuit contains space for protection diodes (antiparallel diodes) and capacitors. Finally, the circuit contains 5 LEDs, one led is a power indicator, the other 4 led are general porpuse flag. This is a perfect circuit to make a car, it is easy to build and too interactive.

Step 1: important issues

Power details

Capacitors

In the board are space to some capacitors, two of them are electrolytic capacitors, C1 is conected to GND and Vin terminal, C8 capacitor is connected to gnd and 5v terminal (microcontroller suply). 

The ceramic capacitor helps eliminte the noise from the motors and the 7805 regulator.

LEDs

The board contains five leds, one of them is a power indicator, it only lights when the circuit is powered. the other four leds are general porpouse indicartos connected to the microcontroller portA. these leds could works as the user wishes, it just need to be programed.

Frequency

The circuit contains an space for a osc crystal, the max frequency allowed is 20 MHz, being this the max frequency allowed by the microcontroller.

"LUZ" port

These three pins are for connecting light sensors, for example CNY70, requires external circuit because the pcb only has suply pins (5v and GND) and a digital read pin connected to B4 microcontroller pin. 

Ultrasonic sensor

The circuit contains four pins to connect an HC-SR04 sensor, this pins are identified by J2 label. The trig pin is connected to A1 microcontroller pin and echo pin from the sensor is connected to B0 microcontroller pin.

These three pins are for connecting