Virtual MCU Base Programmable Timer

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 able to program start time and end time of the timer or specify only the start time. Once the timer get started user may be able to terminate the timer by pressing “OK/Timer Disable” key.

Please note that this system is provided only for demonstration purposes and end user need to calibrate MCU crystal and other associated components to obtain exact 1Hz clock trigger. The Lamp (L1) shown in the simulation model is for the demonstration purposes only. Ignore this component at the prototyping stages. All the source codes and Proteus ISIS simulation files of this project is available to download at google drive.

Comments

CD2003 - yet another simple FM radio receiver

In the last few days, we are looking for some simple FM radio receiver to integrate into one of our ongoing projects. For that, we try several FM radio receiver ICs including TDA7000, CD2003/TA2003/TA8164, CXA1019, and KA22429. Out of all those chips we select CD2003 (or TA2003/TA8164) based receiver for our project because of its simplicity and outstanding performance. Except to CD2003, Sony CXA1019 also perform well but we drop it because of its higher component count. We design our receiver based on Toshiba TA2003 datasheet and later we try TA8164 and CD2003 with the same circuit. Either CD2003 or TA8164 can directly replace TA2003 IC, and as per our observations, TA8164 gives excellent results out of those 3 chips. A prototype version of CD2003 FM radio receiver The PCB design and schematic which we used in our prototype project are available to download at google drive (including pin-outs of crystal filters and inductors ). Except for CD2003 IC, this receiver consist

Arduino superheterodyne receiver

In this project, we extend the shortwave superheterodyne receiver we developed a few years ago . Like the previous design, this receiver operates on the traditional superheterodyne principle. In this upgrade, we enhanced the local oscillator with Si5351 clock generator module and Arduino control circuit. Compared to the old design, this new receiver uses an improved version of an intermediate frequency amplifier with 3 I.F transformers. In this new design, we divide this receiver into several blocks, which include, mixer with a detector, a local oscillator, and an I.F amplifier. The I.F amplifier builds into one PCB. The filter stage, mixer, and detector stages place in another PCB. Prototype version of 455kHz I.F amplifier. In this prototype build, the Si5351 clock generator drives using an Arduino Uno board. With the given sketch, the user can tune and switch the shortwave meter bands using a rotary encoder. The supplied sketch support clock generation from 5205kHz (tuner frequ

Calculator for audio output transformers

Audio output transformers are heavily used in a vacuum tube and some (older) transistor base audio power amplifiers, but these days output transformer are quite hard to find and expensive item. For homebrew projects, the best option is to construct those transformers by ourselves and this script helps to calculate winding parameters for those transformers. This " AF output transformer calculator " script is written using Python and it works with most of the commonly available Python interpreters . The script is available to download at google drive under the terms of GNU General Public License version 3.0 . Homebrewed 25k: 4 output transformer Once supplied the input parameters this script provides a winding ratio, the number of turns required for primary and secondary winding and required copper wire gauges for both primary and secondary windings, etc. We construct several AF output transformers based on results of this script, which including transformers for M