2 Way AC Flasher

Preview

Schematic

you can change speed by adjusting RV1 

Please be careful! This circuit is directly connected with AC !

Read More

LED Multivibrator

Preview

Schematic

If you want change speed of blinking then change values of  C1 and C2. increased values of C1,C2 will decrease speed.

Supply Voltage 3-6V

Read More

LB1403 LED Sound Level Indicator Circuit

Preview

This is a another sound level meter circuit using LB1403N. You can use this for any audio system such as Amplifier, Radio, or TV. As well as you can use this either ac level meters such as vu meters or dc level meters such as signal meters.

Features of LB1403N

• Capable of generating a bar-display for input voltage with 5 LEDs.
• Operates from either AC or DC input voltage because of on-chip rectifier amplifier.
• Lighting levels remain stable to line regulation because of on-chip voltage reference.
• LEDs are driven by a constant current; stable to line regulation.
• Power supply voltage range is wide (3.5 to 16V), for wide range of applications.
• SIP-9 pin package and fewer externally connected component result in smaller space requirements on the circuit board.
• Low noise at LED lighted mode.

For stereo audio systems you need two of this circuit and you can adjust the sound sensitivity by challenging value of RV1.You can directly connect this circuit with output of your amplifier or any other audio system.
Supply voltage for this circuit is 6-12v.

LB1403 VU meter

Read More

LED Knight Rider Circuits - CD4017 NE555

Everyone like to build LED Knight Rider circuits, specially beginners and little kids. So I will post some knight rider circuits and you can find different pattern of the knight rider circuit from here.

LED Knight Rider 1

Pattern 1 Preview

Pattern 1 Circuit

In this circuit LED is running one by one from D1 to D10. after D10, its star from D1 and this will continue until power is disconnected.

LED Knight Rider 2

Pattern 2 Preview

Pattern 2 Circuit

In this circuit LED is running two ways. in first step D1, D3, D5, D7 and D9 is light up one by one and the D10, D8, D6, D4 and D2 is light up one by one after D2, its star from D1 and this will continue until power is down. this is more similar to the circuit of Knight Rider TV Series. how ever this circuit doesn't display a tail like circuit in tv series. if you like to add tail then simply add capacitors between every LED. the value of capacitor depend on input voltage and type of LED. so i can't give a value for capacitor. therefor you have to chosen your own value for this by adding different capacitors from 10-220uf. however i think 47-100uf is good for this.

LED Knight Rider 3 - Shadow

Pattern 3 Preview

Pattern 3 Circuit

This is the same circuit of pattern 1 and only change the polarity of LED. after power is given all the LED s are light up except D1. next all the LED s are light up except D2. this will continue until D10 off. after that it begin with D1 and this will repeated until power is applied. This method also can applied to the pattern 2. RV1 used to change speed of scrolling. Supply Voltage is 5-12v. Change the R1 resistor to 470-1k when you used power supply above 5v.

4017 is a synchronous decimal up counter with decimal-decoder. it count when the signal is applied to the CLK (pin 14).

The NE555 is a highly stable device for generating accurate time delays or oscillation and used to generate clock pulses for 4017.

Read More

7 Band Spectrum Analyzer Circuit using OP Amps

Spectrum Analyzer

Circuit Preview

You can use this circuit for build your own spectrum analyzer for amplifier or any audio equipments.

In this post i will not show the sound level meter circuit and this is only the circuit of the band pass filter for the analyzer. you need to connect outputs of this circuit with sound level indicator circuits such as LB1403 , AN6877 to get full circuit. you need totally 8 of sound level indicator circuits. the last bar show the sound level and if you doesn't like it you can omitted that one and then you need totally 7 of sound level indicator circuits.

For build seven band pass filter here I used LA6458S. but you can use any operational amplifier for this. If you use operational amplifier such as LM324 or TL084 then you need only two ICs for this. because those ICs include four different operational amplifiers and LA6458S include only two operational amplifiers.

By using this circuit you can be able to get 50Hz, 100Hz, 330Hz, 1kHz, 3.3kHz, 6.3kHz and 12.5kHz output and these out put can be directly connected with any audio level meter circuit mentioned earlier.

Couple of year ago I found this circuit from a radio and then I build this one and it worked great..!
Supply voltage for this circuit is 12v.

7 Band Spectrum Analyzer

Read More

AN6877 - AN6878 LED VU Meter Circuit

Preview

This is a sound level meter circuit based on AN6877 and AN6878 series. you can use this for any audio system such as Amplifier, Radio, or TV.

The AN6877 and AN6878 are monolithic integrated circuit driving 7 LED s. The AN6877 respond linearly and the AN6878 does logarithmically for input signal. As output current adjusting pin is set, it can control LED brightness. (by changing value of Rc)

Features  

• 7 LED bar graph display drive
• Linear (AN6877) and Logarithm (AN6878) response
• Adjustable Brightness
• High output current (25mA)

For stereo system you need two of this circuit and you can adjust sound sensitivity by challenging the value of RV1.
Supply voltage for this circuit is 6-12v.

AN687X VU meter

Read More

PIC16F88 Seven Segment Digital Clock Circuit

In the beginning, I posted a clock that used PIC16F84A micro-controller. You can see it here. PIC16F84A is very old IC and it has very less functions. Therefore, today I post a developed version of that clock. It used PIC16F88 micro-controller. PIC16F88 built in many features such as large memory, internal oscillator, ADC and many more. In addition, we can use this IC for our future projects.

Preview

Circuit Created On Dot board

You can use big SSD or LEDs to build this but therefore you should add more transistors. Like this.

for large display

Here I used 4 switches to control the clock.

• SW1 – Edit / Enter
• SW2 – Up Sec / Min
• SW3 – Down Sec / Min
• SW4 – 12Hr / 24Hr
• SW5 – Reset

Click here for 1Hz Oscillator Circuits

Clock Circuits

PIC16F88 Datasheet

16F88 Pin-out

Hex File
PCB and Schematic

Read More

Simple Light Sensor Circuit

Preview

If you need to turn on any device at morning, then you can use this circuit.

This is a light sensor and you can control any device by connecting it through the relay. The relay was activated when the around is light or when we focus a light to the surface of the LDR.The circuit is very simple and you can use a dot board to assemble it and use any power supply to give power.

If you have a 9v or 6v relay then decrease the input voltage according to the voltage of relay. Use
RV1 to change the sensitivity of this circuit.

Light Sensor Circuit

Operation

In dark condition impedance of LDR is very high. Q1 transistor is in off state. because bias voltage coming to the base of Q1 is low due to high impedance of LDR.

At light condition impedance of LDR is goes down and therefore voltage of Q1 base is goes high and after it reach its saturation voltage Q1 activated and bias voltage for Q2 is start to going through R1 and Q1. then Q2 activated and also relay was activated.

If you connect you device across the NC and Com pin of relay then you can also use this as dark activated switch.

Read More

Simple Dark Sensor Circuit

Preview

If you need a bulb to light up automatically at night, then you can use this circuit.
This is a dark sensor and you can control any device by connecting it through the relay. The relay was activated when the nearby is dark or when we covered the surface of  the LDR.The circuit is very simple and you can use a dot board to assemble it and use any power supply to give power.

If you have a 9v or 6v relay then decrease the input voltage according to the voltage of relay. Use RV1 to change the sensitivity of this circuit.

Dark Sensor Circuit

Operation

In normal condition impedance of LDR is low. Q1 transistor is in off state. because bias voltage coming through R2 and RV1 was grounded through the LDR.

At dark state impedance of LDR is increase and therefore voltage of Q1 base goes high and after it reach ~0.5-0.7v Q1 activated and bias voltage for Q2 is start to going through R1 and Q1. then Q2 activated and also relay was activated.

If you connect you device across the NC and Com pin of relay then you can also use this as light activated switch.

Read More

JDM - A Simple PIC Programmer Circuit

Circuit on dot Board

The JDM programmer is one of the simplest PIC programmers available. The design comes from the excellent JDM low cost programmer. It connects direct to the PC serial port using Windows driver software IC-Prog for easy programming. No external power supply is required and a simple board layout is given requiring no special PCB manufacture. Note that the design is limited to the PIC series (12F, 16F and 18F) of chips and cannot be used for In System Programming - ISP.
If you need a more advanced programmer then try WinPic800.

The JDM circuit connects to the computers serial port through a DB9F female connector and the LED are optional but are very useful particularly when testing the circuit.

Connection with 16F84

By connecting below two circuits together, you can able to get a complete JDM programmer for program all pic series.

Circuit 1

Circuit 2

Hardware Testing

1. Connect the programmer to the PC serial port using the Female to Male serial lead
2. Start the IC-Prog software and under 'Settings -Hardware' select JDM Programmer
3. Insert the PIC into the programming socket

IC-Prog interface

WinPic800 interface

IC-Prog
WinPic800
PCB & Schematic

Read More

24Hr Digital Clock and Alarm Circuit Using Logic ICs - CD4017 CD4026

[Updated]
06/05/2018 - Added Month and Date Reset Feature

This is my first clock project, and used logic IC such as 4017, 4026 to build this clock circuit. Its include Date, Day, and Hourly alarm.See below picture.

Preview

It’s very complicated at first sight. But it is not. First of all you can build main circuit and check it work or not.If the circuit work fine, then add other parts step by step to the circuit.

If it’s not work check all component and connections are correct and also check Seven Segment Displays. In my circuit I used LEDs but it is possible to use Seven Segment Displays.
Add &transistors if you use LED or big Seven Segment Displays because this logic ICs can not handle large current. I connect this circuit with 6v backup battery to prevent time lost when the power is fail. In power failure displays are turned off but time is running using battery power.

Full Circuit Diagram

1Hz Signal Generators

To generate 1Hz clock pulse for this circuit here I used circuit of a ordinary clock machine. you can buy a clock machine very cheap price at electronic shops or you can get it from old clock. In below picture you can see most common circuits of clock circuits. By giving power to this circuit we can able to get 1Hz output across the pins that are connected to coil (motor). (But actually we can get only 0.5Hz pulse in one pin. So get 1Hz we need to connect those pins by two diodes. you can see that in the diagram).

Clock circuits

4017 decade counter (1-of-10)

The count advances as the clock input becomes high (on the rising-edge). Each output Q0-Q9 goes high in turn as counting advances. For some functions (such as flash sequences) outputs may be combined using diodes.

 The reset input should be low (0V) for normal operation (counting 0-9). When high it resets the count to zero (Q0 high). This can be done manually with a switch between reset and +Vs and a 10k resistor between reset and 0V. Counting to less than 9 is achieved by connecting the relevant output (Q0-Q9) to reset, for example to count 0,1,2,3 connect Q4 to reset.

 The disable input should be low (0V) for normal operation. When high it disables counting so that clock pulses are ignored and the count is kept constant.

 The ÷10 output is high for counts 0-4 and low for 5-9, so it provides an output at 1/10 of the clock frequency. It can be used to drive the clock input of another 4017 (to count the tens).

4026 decade counter and 7-segment display driver

The count advances as the clock input becomes high (on the rising-edge). The outputs a-g go high to light the appropriate segments of a common-cathode 7-segment display as the count advances. The maximum output current is about 1mA with a 4.5V supply and 4mA with a 9V supply. This is sufficient to directly drive many 7-segment LED displays. The table below shows the segment sequence in detail.

 The reset input should be low (0V) for normal operation (counting 0-9). When high it resets the count to zero.

 The disable clock input should be low (0V) for normal operation. When high it disables counting so that clock pulses are ignored and the count is kept constant.

 The enable display input should be high (+Vs) for normal operation. When low it makes outputs a-g low, giving a blank display. The enable out follows this input but with a brief delay.

 The ÷10 output (h in table) is high for counts 0-4 and low for 5-9, so it provides an output at 1/10 of the clock frequency. It can be used to drive the clock input of another 4026 to provide multi digit counting.

4026 display chart

CD4073 triple 3-input AND Gate

The 4073 has three separate 3-input AND gates which you can use independently.

Truth table

The truth table of each individual gate is:

C B A Output

0 0 0  0

0 0 1 0

0 1 0 0

0 1 1    0

1  0    0  0

1 0 1  0

1 1 0    0

1 1   1 1

where '0' represents a LOW voltage, and '1' represents a HIGH voltage.

Basic operation

You can investigate the behavior of a single 3-input AND gate using this circuit:

The inputs of the gate must be connected, either to LOW or to HIGH, and must not be left open circuit. This is the function of the input switches with their pull-down resistors. To avoid loading the output of the gate, a transistor switch indicator circuit should be used. It is good practice with CMOS circuits to insert a decoupling capacitor, 47µF or 100µF, across the power supply. (This helps to prevent the transfer of spikes along the power supply rails.)

UM348X

The UM348X series is a mask-ROM-programmed multi instruction melody generator, implemented in the CMOS technology. They are designed to play the melody according to the previously programmed information and capable of generating 16 songs with 3 instrument sounds, the piano, the origin and the mandolin.

The devices also included a per-amplifier which provide simple interface to the driver circuit. The UM348X series is intended for applications such as toys, door bells, music boxes, melody clock/timers and telephones

Month and Date Reset

Month and Reset Circuit

This is a newly added circuit and use 16F628A micro-controller. you have to program it before use. the purposes of this circuit are show month and reset date according to the month. Ex: Jan 31, Feb 28, Etc. PIC use its internal oscillator and circuit is very simple. To save pins, Month shows binary format.
Ex: 1=0001, 2=0010, 3=0011, etc.
For power supply and more details please refer device datasheet. 

Code

/******************************************************************************* Month and Date Reset - 16F628A Copyright (C) 2014 Praneeth Kanishka This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses >> Email: scorpionzblog@gmail.com >> Web : http://scopionz.blogspot.com *******************************************************************************/ int count=1, month=1, date=1; const char day_month[] = {0,31,28,31,30,31,30,31,31,30,31,30,31}; // Interrupt Service Routine (ISR) void interrupt() { if (INTCON.INTF) // Check for interrupt { PORTA.F2=1; count=count+1; delay_ms(5); PORTA.F2=0; if(count>day_month[month]) { count=1; if(++month>12) month=1; PORTA.F3=1; Delay_ms(5); PORTA.F3=0; PORTA.F2=1; Delay_ms(5); PORTA.F2=0; } PORTB = month<< 0x07="" a0="" clear="" cmcon="" comparators="" delay_ms="" disable="" flag="" if="" intcon.intf="0;" intcon="0b10010000;" interrupt="" interrupts="" main="" month="" nable="" option_reg.intedg="0;" pcon.oscf="1;" porta.f2="0;" porta="0x00;" portb="month<<4;" rb0="" trisa="0x03;" trisb="0x01;" void="" while="" z="">12) month=1; PORTB = month<< count="" delay_ms="" if=""> day_month[month]) { count=1; PORTA.F3=1; Delay_ms(5); PORTA.F3=0; } PORTA.F2=1; Delay_ms(50); PORTA.F2=0; Delay_ms(400); } } }

Logic Clock Circuit
Month and Date Reset Circuit

Read More

64x8 LED Matrix Moving Display Circuit - 18F2550

Matrix Display

LED dot matrices are very popular and it can displaying information such as both static and animated text and images. you can see it at gas stations displaying the gas prices, or in the public places and alongside highways, displaying advertisements on large dot matrix panels. In this project, we can use LED dot matrix interface with a micro-controller to display static characters and symbols.

This circuit of a Dot Matrix is based on the PIC18F2550 micro-controller and software is pic basic pro and it also include Proteus ISIS simulation and Kicad PCB files.

Circuit Board

This circuit has 8 of 8×8 matrices and currently I used only 3 matrices.but you can use up to 8 matrices. I added two different hardware versions in download. but firmware is same. In my circuit I used CD4541 PCB and bypass the transistors. But brightness of your displays are very low or you need extra brightness then used transistors. and remember to add heat sink to regulator ic.

Character Set

The most difficult thing about using the dot matrix LED display is defining the characters. Basically for ASCII characters you need an array of 128 blocks each having 8 column data numbers.
The usual way is to get out a piece of graph paper and define your characters by drawing blocks where a pixel is on. You then translate each line into hex (binary to hex is very easy) and then transfer this information to your program source code.

Theory of LED Dot Matrix Display

In a dot matrix display, multiple LED s are wired together in rows and columns. This is done to minimize the number of pins required to drive them. For example, a 8×8 matrix of LED s would need 64 I/O pins, one for each LED pixel. By wiring all the anodes together in rows , and cathodes in columns, the required number of I/O pins is reduced to 16. Each LED is addressed by its row and column number.Characters can be displayed by fast scanning of either rows or columns.

Video Of Matrix Display

How to compile?

First install MicroCode Studio
Then install PICBASIC PRO Compiler
Finally install MPLAB IDE

Now open MicroCode Studio
Click View >> Compile and Program Option >> Compiler >> Find Automatically
Else you can manually search your pbp folder (Default C:\pbp)
Next Click Assembler >> Find Automatically
Or you can manually search by clicking Find Manually button  (Default C:\Program Files\Microchip\MPASM Suite)
Then open 18F2550.bas with MicroCode Studio, choose 18F2550 and press F9 or go to project >> compile

Now you were done.

PIC18F2550 Datasheet

pin connection

Matrix Display Source Files
Matrix Display Hex and Proteus
74154 PCB and Schematic File
4514 PCB and Schematic Files

Read More