Dilshan R Jayakody’s Web Log

This is 8 channel CMOS logic probe and pulsar which is useful when designing, testing and faultfinding in digital circuits. This circuit is designed using commonly available CMOS logic ICs which including a couple of 4069 hex inverters and 4040 binary counter. A prototype version of 8 channel logic probe and pulsar The logic probe of this system is based on 4069 hex inverters and it indicates logic high and low states with 2 LEDs. Logic pulsar of this circuit is capable to generate 12 frequencies and highest frequency it can generate is 420kHz.  This pulsar generates a square wave with 50% duty cycle and it's average rise time is 16µS. Both schematic and PCB design of this logic probe and pulsar are available to download at google drive . In this schematic, all LED-L connections should connect to the anode of LEDs and cathode should be connected to the VSS terminal of J31 ( LED-L-H ) connector. All LED-H connections should connect to the cathode of LEDs and anode must

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