Dilshan R Jayakody’s Web Log

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...

HAKKO 907 is popular and commonly available soldering iron in the electronics field. To drive those soldering irons user needs to have HAKKO or any other compatible soldering station. The biggest problems with those soldering stations are there higher price tags and limited availability in the local market. Because of those problems, we decided to create our own soldering station, and for that, we choose " Chinese " version of HAKKO 907 soldering handle. Now Chinese versions of 907 compatible irons are available on eBay for less than 5USD. As per our observations, those Chinese versions of soldering irons look and perform almost similar to genuine HAKKO 907 iron(s). To keep it simple we choose LM358 dual operational amplifier IC to monitor the 907's thermocouple and drive the TRIAC. The entire control circuit of this soldering station is powered by single rail 5V DC power supply. To drive both handle and station we use 12V-0-12V 8A step-down transformer. Interna...