Dilshan R Jayakody’s Web Log

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...

This is simple telephone locator-light which is used to identify the ringing telephone at the night / low light conditions. This unit only activates at low light conditions and it automatically turns off lights after 12 - 15 sec. from the last ring. This telephone locator is mainly based on NE555 timer IC and it is designed to work with 6V 0.5A - 1A power source. This given schematic support a maximum of two 3W power LEDs. During the assembly, it is important to place both LEDs and LDR in two separate positions to avoid any interference to LDR from LEDs. Also, note that in some counties it is illegal to connect custom circuitry into phone lines, please check your local regulatory bodies is concerned. Schematic and PCB designs of this unit are available to download at google drive .

This is high quality stereo digital audio amplifier with PLL synthesized FM radio receiver. Some of the high level specifications of this receiver are listed in below: Audio output power: 4W + 4W (with 8ohm speakers) Input sources: FM and 3 external stereo line inputs FM frequency range: 88.00MHz – 108.9MHz Supply voltage: 12V – 15V (2A current source is recommended) Tone control options: Bass, Treble and Loudness control Bass / Treble boost: 14dB Bass / Treble cut: 14dB Station memory: Preset 10 FM radio stations FM tune options: Auto and Manual with 25 kHz steps Key components of this audio system are ATmega32A - 8bit microcontroller, TT502 ( TEA5767 ) stereo FM radio module, PT2314 audio processor and μPC2002 audio power amplifier. This system is design to work with 12V - 15V (2A) DC power source and KA7632 multi-output regulator is used to manage power requirements to the above mentioned components. Prototype version of digital audio amplifier User interfa...

UPS system is a common peripheral in computer field. Now most of these UPSs are equipped with USB driven system shutdown software. But some of the cheap UPS system may not have software controlled PC shutdown systems and some of them had some limitations too (for example operating system compatibility issues, supporting for multiple nodes, etc.). In this post we design power failure monitor with centralize power switch for array of PCs. Using this system administrators can turn on multiple PCs with single button press and all of these PCs get power down automatically at power failure. To reduce cross platform issues we design this interface to work with main-board power switch and because of this administrators may not need any special software for this system. Most important point of this system is its independence with UPS hardware. Prototype of centralize power switch project Main controller of this system is PIC10F200 - 8bit microcontroller. Thanks to its SOT-23 package w...