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...

This is TCS230 based Bluetooth color picker prototype which we build to test the concept. In here the idea is to extract color from any physical object and transfer it to PC / mobile. To test this concept, we use low-cost TCS230 color sensor. A prototype version of color picker on a tiny breadboard. TCS230 is programmable color light-to-frequency convert IC. This chip produces square wave output with frequency directly proportional to the light intensity. To drive this sensor and capture its output we used PIC16F628A microcontroller. The processed output is then transferred to the host using the HC-05 Bluetooth SPP ( Serial Port Protocol ) module. In PC we wrote small Python script to display captured value and color in a Window. In this design, we drive the TCS230 sensor with 20% frequency scaling. The entire circuit is built using commonly available modules and components. For the color sensor, we use the 8-pin TCS230 sensor module which is commonly found in eBay and other...

We initially developed this USB atmospheric pressure monitor to study some operating characteristics of Bosch BMP180 sensor . BMP180 is a low-cost sensor for measuring barometric pressure and temperature. According to the datasheet this sensor can use to measure pressure ranging between 300hPa to 1100hPa . This sensor is introduced a couple of years back but still, it is popular due to lower cost and simplicity of its interface. BMP180 based sensor module We did this unit to test the BMP180 sensor more accurately and to study its behaviors. This unit is based on PIC18F2550 microcontroller and the main reason to select this MCU is because of its built-in USB 2.0 interface. BMP180 sensor monitor application To display sensor calibration data and it’s readings we did small windows application. This application display and plot temperature and pressure readings captured from the BMP180 sensor. This unit is programmed to work as a USB HID device and no special device drive...

This is a simple sensor kit to drive 8 active or passive sensors and log its data into a remote Android application. This system also has an option to activate an external device(s) based on the specified threshold of sensor data. This sensor controller is mainly built around the Raspberry Pi Model 3 B+ and PIC16F877A MCU. PIC16F877A MCU is used to interface/select sensors and it's built-in 10bit multi-channel ADC is used to capture the analog signals from sensors. During the prototype stage following sensors are tested with this system: LM35 precision temperature sensor MQ7 Carbon Monoxide gas sensor Electret Microphone NSL-19M51 LDR HC-SR501 PIR sensor A3144 Hall effect sensor Apart from the above list this system can use to drive and capture most of the other analog/digital sensor signals such as current sensors, pressure sensors, chemical sensors, humidity sensors, etc. In this system, Android monitoring application is designed to connect with the sen...

CoCA "Emerge + Tech" - Musical plants is an electronics, software and plants base exhibit we developed for Cinnamon Colomboscope 2016 exhibition. This installation will feature a touch-sensitive sensor that will generate a soothing sound from each plant. By interacting with individual plants, the audience can create musical compositions. The sensor unit of this project consists of 14 high sensitive, configurable level detectors and USB interface. In this sensor unit, we use Samsung's KA2284 as an amplifier, level detector, and PIC18F4550 8-bit MCU as data multiplexer and USB I/O controller. PC817 optoisolators are used to interface between analog front-end and digital data processor. In this design, both analog and digital circuits are physically and electronically isolated to minimize the noises and interferences. In this design, we use KA2284 because it is commonly available in the local market (in Sri Lanka) and costs less than 0.1 USD. To reduce the interfer...

" Musical trees " is a part of creative art installation and this project is capable to produce different audio tones by detecting a human touch to its attached plants. The existing version of this driver is capable to monitor 8 plants and produce different sounds for each plant. A prototype version of "Magic Tree" project with 2 plant samples. This project is built around PIC16F628A 8-bit microcontroller and PT2399 echo processor IC. To drive the sensor electrodes we use pair of CD4011 quad 2-input NAND gate ICs. This prototype uses TDA7052 1W audio amplifier IC to drive the speaker(s). The existing firmware of PIC16F628A is designed to produce tones in between 155Hz to 1244Hz and this range can be changed by modifying the supplied firmware source code. In this design, the PT2399 echo processor IC is used to get the more natural (/ deep) sound effect by adding some reverberation to the output. Schematic and firmware of this project are available to ...

ZFM-20 is an optical fingerprint sensor module series developed by Zhiantec . Resolution of these fingerprint modules are 256×288 pixels and depending on the module it can be accessible over UART or USB interfaces. Other than capturing fingerprints this module has inbuilt DSP to process and verify captured fingerprints. This ZFM-20 fingerprint library is developed to capture and retrieve fingerprint images from the above sensor module. The main purpose of this library is to use ZFM-20 sensor with PC as a low-cost fingerprint capture unit and because of that, in-module fingerprint processing and verification functions are not implemented in this library. ZFM-20 fingerprint sensor test setup with CH340G serial to USB converter. ZFM20-LIB is x86 native shared library and it's implemented using Lazarus / FPC . This library is developed to use with most of the programming languages which including C , C++ , Delphi , FPC , Microsoft .net framework based languages, etc. Objec...

This is an easy to build "liquid level monitor" and "automatic control system". This control system is mainly based on Microchip’s PIC16F630 8bit MCU and few combinatorial logic ICs. This system is specifically design for industries where there is a requirement of maintaining a liquid level at a particular level. The level monitoring stage of this system can capable to sense up-to 8 liquid levels and its trigger point can be programmed at anytime by using its simple 2 button user-interface. This system is design to work with 12V (or maximum of 25V) DC power source and its sensor system is capable of sensing liquids with resistance of up-to 30k to 35k. To minimize the sensor noise and output instability, the control software is equipped with simple 20-tap FIR like filter system. The output stage of this system is design to work with 12V to 24V DC relays and it is recommended to use Tyco K10 series or similar kind of relay with this system. The trigger point o...