Dilshan R Jayakody’s Web Log

In this project we design low cost high performance programmable home security system using few LDR’s as an input sensors. When above sensor(s) get triggered system may dial the user specified phone number (using build-in DTMF generator) and activate the high power audio alarm and lights. All the parameters of DTMF generator, audio alarm and light interface are programmed through the RS232 serial interface. Current firmware of this system presents interactive control system through the RS232 interface. This control system consist with the menu driven configuration options, self tests, system report generators, etc. This system also contain 5W (with 4Ω speaker) audio alarm with three selectable tone configurations, which include Police siren, Fire engine siren and Ambulance siren. This system uses a Microchip’s PIC16F877A as a main controller, LM339 as sensor interface, UM3561 as a tone generator and μPC2002 as a speaker driver (audio amplifier). LM7805, LM7812 and LM317 voltage...

Logic analyzers are allowing us to monitor and /or diagnose a large number of digital signals simultaneously and these devices are essential when developing complex digital systems. In this project we design simple 8 channel USB logic analyzer with Windows version of driver software. Design of this logic analyzer is based around Future Technology Devices FT245 USB FIFO chip. With the given oscillator this system takes 14MSPS (Mega samples per second) and this system is design to work as (USB) self powered device (without any external power source). Driver part of this project is based on FTD2XX driver and GUI is developed using Delphi. Current version of driver software is design to work with Windows NT operating systems and it is highly recommended to use it with 1360 × 768 or with higher video resolutions (with aspect ratio of 16:9). This design also contains real-time logic level indicators to monitor "low frequency" signal levels and construction of that portion i...