Dilshan R Jayakody’s Web Log

In this design we present an electronic number display panel using low cost and low power electronic components. This proposed design is mainly based on CD4510 - CMOS up/down counter and SN74LS47 - BCD-to-Seven-Segment Decoder/Driver. With the existing configuration, this counter may be able to count (up/down) from 00 to 99 and it can easily extend to more digits by setting up additional CD4510 and SN74LS47 chip pairs. Current system is also equipped with the beeper (which based around NE555 timer IC) to indicate the increment or decrement of the count. This system is design to work with DC 9V – 12V (500mA) power supply and at the time of testing we use 10V (2.5A) DC power source to check this system. This proposed system contain 7805 regulator and it is necessary to apply suitable heat-sink to this regulator. In this project, we design PCB using double sided PCB and make dimensions and shapes according to the existing enclosure of old electronic number panel system. It is not ...

In this article we implement virtual (computer simulation base) microcontroller driven programmable timer using Proteus VSM. This proposed system is design using Microchip PIC16F877A – 8bit microcontroller and its system software is developed using MikroC PRO 3.2 for PIC. Most of the components in this proposed design are based on Proteus VSM - simulation models and we assign standard component names to them to assist in actual prototyping. In this simulation we use PIC16F877A as main system controller and 4 row monochrome LCD display unit with HD44780 compliant controller (in 4bit mode). This proposed simulation model is design to work with +5V supply voltage, but it can also operate using battery power (3 × 1.5V). When implementing this system for the real-life use, it is highly recommended to integrate battery backup facility to this system. It helps to drive this system continuously with minimum amount of disturbances. According to the supplied source code, end user may be a...

This is a simple microcontroller base implementation to drive 2 digit 8 pin seven segment display (SSD) unit. For this implementation we use Microchip’s PIC16F84A – 8bit microcontroller unit and Proton+ PICBASIC compiler. Compared with other SSD units this SSD unit needs special algorithm to drive it. Some of the logical procedures to drive this SSD unit are illustrated in below, This illustration is valid only for single digit of target SSD unit and it can easily expand to 2 digits by activating pin no 5 and 6 with appropriate inputs. In attached design we use PIC16F84A MCU with 4 × 2SC945 general purpose NPN transistors to drive this TOD-4201LR SSD unit. This proposed system is design to work with +5V DC power supply and may not need any additional data source. Supplied software for this project is for demonstration purposes only and it perform counting from 0 to 99 and then reset back to 0. To generate the output user need to assign required number to the value variable an...

In this project we design miniature stereo computer speaker driver using TDA2822 power amplifier IC. Main goal of this project is to design small stereo power amplifier which may be able to fix inside the small speaker boxes. Supplied PCB of this project has dimensions of 4.5cm × 4.5cm, which include both power amplifier and PSU. Some of important technical specifications of this project are listed in below, Recommended Supplied Voltage : 5V – 9V AC Output Power : (with 8Ω load and 7.5V AC Power Source) : 2 × 1W Voltage Gain (with feedback) at 1kHz input signal : 38.5dB Total Harmonic Distortion : (with 8Ω load and P 0 = 150mW) 0.2% Channel Separation : 50dB When wiring the project it is recommended to place screen-wires to the input terminals of amplifier and keep them separate (away) from AC power lines and transformer unit(s). It is not necessary to install heatsinks to TDA2822M IC (with given input and output parameters). Complete schematic, PCB design and documen...

A7VVYNHHASU7

In this project we developed 4 inputs (Audio and Video), remote control operated video switch for general home use. This design is mainly based on Microchip PIC16F630 8bit MCU, 4052 differential 4 channel analog multiplexer, TSOP1838 infrared receiver module and 7447 BCD to seven segment decoder. With a given schematic and PCB design users can switch 4 different audio and video sources using compatible remote controller. Current version of this project is work only with most of Sony remote controllers (which based on Sony SIRC protocol) and it can be easily extend to Philips RC-5 protocol with some minor modifications of PIC16F630 software system. In this design we incorporate small single transistor video amplifier to its output stages to amplify the (chroma) part of video signal. Audio output stage of this system may not need any AF amplifier. (In the designing stages we notice some clipping of input signal in 4052 analog multiplexer, but it is not much noticeable in practical e...

Nowadays DSL splitter is a common unit in telecommunication and it is used by most of the ADSL users to obtain the maximum performance of the connectivity. Technically DSL splitter is an analog LPF (low pass filter) which is used to prevent interferences between analog telephone device(s) and DSL support units. In this project we describe how to build miniature ADSL splitter at home with grater simplicity and with minimum amount of cost. To build this unit user need to use few generic components which include pairs of 330µH inductors and 1R resistors, 0.0033MFD capacitor and three units of RJ11 PCB connectors. We successfully test this splitter with our local ADSL connection and it gives equal performance of commercial DSL splitter. The complete schematic and PCB diagram (Eagle) of this ADSL splitter is available to download at google drive