Dilshan R Jayakody’s Web Log

This 12V uninterruptible power supply initially designs to drive my fiber optic modem/router. The key reason to build this power supply is to get continuous internet and phone connection during power failures. Core components of this power supply are a constant voltage charger, 12V DC power supply, AC line monitoring unit, and 12V high capacity sealed lead-acid battery. The entire system designs using locally available components. Prototype version of 12V UPS system The charging circuit of this system builds around using the popular LM350 voltage regulator. This regulator calibrates to provide both 14.4V fast charging and 13.6V trickle charging. Based on the condition of the battery, the MCU will determine the appropriate charging mode. At the online state, the LM2576-12 switching regulator provides 12V output to the driving system. (in my arrangement, a fiber optic router). Block diagram of the 12V UPS system The PIC16F688 MCU monitors the AC line and battery to controls the output...

This is an experimental stepper motor driver for Celestron CG-4 German equatorial mounts . This unit is functionally equivalent to the Celestron dual-axis motor driver , and we developed it as a replacement unit for the original Celestron driver. The prototype circuit board of the motor controller unit. The core component of this motor driver is PIC16F88 8-bit MCU. This MCU is responsible for driving two motors and scanning the user inputs. As an original unit, this system also got a clock driver for the right ascension (RA) axis. This system uses two L293 motor drivers to drive the right ascension (RA) axis and declination (DEC) axis motors. This unit is designed to work with 6V bipolar stepper motors, which include in the telescope mount. The LM350 voltage regulator is used to maintain power to both stepper motors. Internal view of the prototype enclosure. This replacement motor drive provides all the functionalities of the original unit, which including manu...

This is an easy to build " high-bright LED" night light, which I was design and developed in weekend to replace my existing 5W ( filament base) night lamp.  This circuit is mainly based around TL494 PWM driver IC and LM350 - 3A adjustable voltage regulator. The LED used in this project is 9V - 10W high bright LED and this given design is capable to drive maximum of six, 10W LEDs. Microscopic view of 10W High Bright LED with controlled input This unit is design to work with 12V to 30V DC power supply and it can withstand for voltage fluctuation around 12V to 35V. The schematic of this unit is available at upvater.com under the terms of CERN OSH 1.1 License .