Tuesday, August 30, 2016

CoCA Emerge + Tech - Musical plants project

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.


Sensor unit of this project consists with 14 high sensitive, configurable level detectors and USB interface. In this sensor unit we use Samsung's KA2284 as amplifier, level detector, and PIC18F4550 8-bit MCU as data multiplexer and USB I/O controller. PC817 opto-isolators 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 local market (in Sri Lanka) and costs less then 0.1 USD. To reduce the interferences we use shielded cables between plants and sensor ICs. With the special wire we are using we may be able to extend the sensor connectivity up to 3m.

Sensor board of musical plants project.

PC application of this project is developed by using HIDAPI and irrKlang libraries. This application is designed to work with Microsoft Windows operating systems and we tested it on Windows 7 and Windows 10.

This project is an open source hardware project released under terms of MIT and CC BY-SA licenses. All the content of this project are available to download at hackaday.io or github.com. Conceptual details of this project is available at CoCA homepage.

Sunday, August 28, 2016

Sony TC-500 reel to reel player restoration

TC-500 is 4 track stereo reel to reel player which is build around 1960 - 1970 by Sony Corporation. This is vacuum tube base reel to reel player with 2 × 3W audio output power. TC-500 is dual speed (3¾ and 7½ ips) tape recorder and it support reels up to 7 inches (18cm). Amplifier stage of this tape recorder is build around 12AX7, 6AU6 and 6AQ5 vacuum tubes and 12BH7 tube is used in biasing oscillator. Other than above tubes, 6CA4 is used in PSU for rectification.

Restored Sony TC-500 reel to reel tape recorder.

Recently we got a chance to restore TC-500 reel to reel player which we got from one of our friend. The player which we got is heavily damaged and we spend nearly 2½ months to restore this player.

In first stage of restoration we disassemble mechanical parts of this player and clean everything. In this player capstan idler wheel and take-up idler wheel is damaged beyond repair and we reconstruct those wheels using rubber sheets.