Dilshan R Jayakody’s Web Log

In last year we spend a lot of time and effort to wire our new house by ourselves. To complete this job we took nearly 2 ½ months and it includes wiring, fixing electrical fittings, communication equipment, etc. In this post, we describe how we archive this task with some technical details. Due to a large number of electrical points, we decided to use 3 phase electrical wiring in our house. To make it simpler we divide entire house wiring into 3 isolated circuits with 3 separate distribution boards. High-level design of our AC wiring systems is illustrated in the below diagram. High-level electrical wiring diagram up to distribution boards In the above circuit, the 3 phase AC line is first fed into 4-pole 40A isolator . Then it connected to 4-pole RCCB with 3 separate indicator lights. We use indicator lights to see the status of each phase, easily at any time. After RCCB we fed each phase into 3 separate distribution boards. As seen in the diagram the first (phase) circui

In this post, we describe the fan controller which we designed for our 9U wall mount server cabinet. This fan controller is designed to drive a 12V DC cooler fan with pre-configured intervals or by monitoring the temperature of the server cabinet. The final version of the fan controller with DC brushless fan and 12V - 60W PSU. Core components of this fan controller are CD4060 binary counter, LM35 temperature sensor, and LM358 operational amplifier. In this design, CD4060 has used as long duration timer and it can be configured to trigger cooler fan from 1-minute and up to 4-hour. In this design, an LM35 temperature sensor is used to activate cooler fan in specified temperature. This sensor stage is useful to drive cooler fan when timer stage is in an inactive state. To control the cooler fan we use AP9971 dual N-channel power MOSFET transistor. We design this system to drive 12V cooler fans up to 2A of current. To test this controller we use commonly available 120mm × 120mm