Dilshan R Jayakody’s Web Log

Today Carbon Monoxide ( CO ) meters are available in different forms. Overall, Carbon Monoxide meters sense CO fast and display the amount to the user and trigger alarm if it reaches a critical level. Compare with most of the DIY Carbon Monoxide meters, the project which we described in this article does not need any development platform or MCU / firmware. The Carbon Monoxide meter in this project design around using general-purpose ICs, such as NE556 and LM3914 . Prototype version of Carbon Monoxide meter The main component of this meter is the FC-22 CO Gas sensor module . This module consists of the MQ-7 sensor and can use to detect CO gas concentrations, anywhere from 10 to 10,000ppm. Apart from the sensor, this module consists of the LM393 comparator to detect the trigger level. In this design, we use both analog and digital output of the sensor module. The analog output use by the LM3914 LED driver and alarm system is drive using the digital output. Home made PCB with align...

Automated Home Security system is PIC16F877 based security system with following core features, Support automatic phone dialing using DTMF tones Support inputs from three optical sensors Control external device(s) Built-in alarm with external audio output Allow total customization to the end-users (such as program phone numbers, setup device control sequence, etc) without changing the source code. Password protected system setup In this design we use PIC16F877 8bit microcontroller as main system controller, NE556 dual timer as an alarm system and 7805 as power regulator. To miniaturize the final product we use some amount of surface mounted parts with this design. Application program(s) of PIC microcontroller is developed using C programming language and release under the terms and conditions of GNU General Public License. In this design we use some special electronic components/modules which include LCD display module, 4x4 keyboard matrix, telephone isolation transforme...