STM32L Discovery Kit

A friend gave me an STM32L-discovery kit. It was my first 32-bit device and packed with the power of ARM-Cortex M3 processor.

My STM32L-Discovery

I will post all updates about my progress using this device.
I already done some experiment with this and I know the adventure with STM32L Discovery will be a long way to go.

Digital Clock Using PIC16f628a Microcontroller

This is a very basic digital clock that can be done using a microcontroller. I particularly used a PIC16f628a.

You can also check my digital clock based on 74ls90
here --> http://circuitdesolator.blogspot.com/2010/12/digital-clock-based-on-74ls90.html

Here's the picture of my digital clock prototype

 

This is the schematic of the device:

 Notes to remember:

1. Put resistors from 7447 to the seven segment display pins(a-g) as current limiter resistors
2. You need to start up you're clock at exactly 1200am/pm.



-------------------------------------------SOURCE CODE-----------------------------------------------

//Digital Clock using PIC16f628a microcontroller
//Design by: circuit_desolator
//Date: April 2011

#include<htc.h>

#define _XTAL_FREQ 4000000

__CONFIG(INTIO & WDTDIS & PWRTDIS & UNPROTECT & BORDIS & LVPDIS);

unsigned int hours = 0;
unsigned int mins = 59;

unsigned int timer = 0;
unsigned char mpx_cnt = 0;
static unsigned char mode = 0;

void interrupt ISR(void)
{   
       
            {       
            timer++;
           
            if(timer > 19650)
            {
                mins++;   
                if(mins == 60)
                {           
                    mins = 0;
                    hours++;
                    if(hours == 13)
                    hours == 1;                   
                }
               
                timer = 0;
            }
        }
       
        switch (mpx_cnt)
        {
            case 0:
                PORTB = hours/10;
                RA0 = 1;       
                mpx_cnt = 1;
               
            case 1:
                PORTB = hours%10;
                RA1 = 1;       
                mpx_cnt = 2;
           
            case 2:
                PORTB = mins/10;
                RA2 = 1;       
                mpx_cnt = 3;
           
            case 3:
                PORTB = mins%10;
                RA3 = 1;
                mpx_cnt = 0;
        }
   
        T0IF = 0;                //clear TMR0 interrupt flag   
}


void init_Timers(void)
{
    GIE = 0;               
   
    T0CS = 0;               
    PSA = 0;                                           
    PS2 = 0;              
    PS1 = 0;              
    PS0 = 0;

    T0IF = 0;               
    T0IE = 1;                  
    TMR0 = 6;                                                                                               
   
    GIE = 1;             
}

void main()
{
    TRISA = 0x00;
    TRISB &= ~0x0F;
    TRISB |= 0xF0;
   
    init_Timers();
   
    while(1);
}

---------------------------------------SOURCE CODE--------------------------------------------

Simple Line Following Mobot

A year ago I built a simple line following mobot. It doesn't use any microcontroller(Arduino, PIC, Atmel, etc.) and even logic ICs.

Simplest Line Following Mobot

This line following mobot uses basic electronic components. Actually, the circuit for this mobot is based on the previous project light/dark activated switch.

The chassis and wheels of the robot are recycled materials. The body is from a box of cookies and the wheels are from the container of wafer stick. I also added a wristband from one of presidential candidates last election for the additional traction of the wheel.

The whole circuit for this mobot is not mounted on a pcb nor a protoboard but on a mini-breadboard. I also uses scrap components for this mobot I found on my bin. 

 

The circuit on the mini-breadboard

This is the circuit of the simple line following mobot.

Basic components are used in this mobot. I uses the following components(all in pairs): bright leds, resistor, variable resistor, ldr, general purpose npn transistor, signal diode, spdt relay and a geared dc motor. 

Here are some pictures of the mobot parts:

Top view of the mobot

DC Geared Motor with recycled wheels.

Sensor part: pair of LEDs and LDRs.

Powered up!

Isometric view of the robot

This is a simple demo video showing the performance of the mobot:

Quiz Bee Buzzer Circuit using PIC16f628a

This is a simple simulation on implementing a Quiz Bee Buzzer using a PIC microcontroller. 

*source code to be followed..

PIC Uart to PC's Serial Port Communication Circuit

This is a simple circuit for communicating PIC to PC's Serial Port

It uses a hardware UART of PIC16f628a. A level converter used is a max232 chip.

Please refer to the datasheet of both IC to check its vcc and ground pins.

Here's the schematic:

Simple Analog Comparator Circuit using lm311

This is one of the common circuit blocks being used both in digital and analog electronics. Its output is dependent on the relationship of its two input pins. One of the inputs is set to give the reference voltage while the other one is commonly connected to different sensors. If the reference voltage was overcome by the input connected to the sensor, the output of the comparator changes.

In this circuit, the we'll use an LDR.

 

The advantage of a comparator IC than an opamp used as an comparator is the property of IC comparators to be open collector output. Having this feature, we can set the output of the comparator beyond its biased voltage.

Traffic Light Circuit (based on 4017)

This is a simple design of a traffic light project that uses 4017 IC. This circuit demonstrate a simple two traffic light. 

The clock source is not included in the diagram but you can use 555 astable circuit as an oscillator.

The time of switching of the lights are in proportions.

3/10 for green

2/10 for yellow 

5/10 for stop

In the schematic, a traffic light model was used in the simulation. But in the actual, you can implement it using LEDs.

Here is the schematic of the traffic light circuit:

 

This is a demo video: