Dilshan R Jayakody’s Web Log

Signal injector and the tracer is a very useful device when troubleshooting electronic audio equipment. We decided to build this signal injector by inspiring the article available in June 2016 - Everyday Practical Electronics (EPE) Magazine ( Audio Signal Injector and Tracer by John Clarke - Page 22 to 29). The signal injector design in EPE magazine is simple but we got few issues while constructing that circuit. The main issue is that LMC6482 is not available to buy in the local market. After few months wait we got a couple of ICs from eBay for LKR 600.00. The second issue is its output is not enough to drive most of the loudspeakers. After prototyping EPE design we decided to build similar sort of signal injector and tracer with commonly available ICs and with more powerful power amplifier stage. For our design, we use the LM358 operational amplifier IC which is commonly available in the local market (for LKR 15 to 20). For the power amplifier, we use LM386 low voltage power...

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...