RTC based automatic LED lamp

This is a real-time clock based automatic LED lamp which we originally designed to use as a night light. This lamp can be programmed to turn on and off at the specific time of the day. For example, it can program to turn on at 6 PM on each day and to turn off at 4 AM the next day.

The core component of this project is PIC16F883 MCU and its firmware is developed using MikroC Pro for PIC. We select this MCU because of its 7 KB flash memory, I²C, UART, E²PROM and built-in 8-bit and 16-bit timers. In this system, we use DS1307 RTC because of its availability in the market and lower external component count.

A prototype version of RTC Lamp

This lamp is designed to work with commonly available 7W LED panels. In our prototype design, we use 7W 24V warm-white LED module to test this system. To drive other LED modules change the value of the R5 resistor of the current limiter circuit.

This system is designed to program using the RS232 serial port. A user can modify system time, light start and end times by connecting this system to any computer through RS232 serial port. To program and view system information user can use any serial terminal application like minicom, putty, etc.

Once the system is connected to the host PC it can switch to programming mode by sending Enter or Space keystroke through the serial terminal.

This unit is designed to work with 24V - 3A power supply unit. 3V button cell is required as a backup power source of DS1307 RTC. Supplied PCB is designed to work with CR2025 or CR2032 type button cells.

Final view of the prototype model

For this project, we use commonly available, less expensive electronic components and in PCB design we use all "through-hole" type components. LED module, heat-sink, and lamp enclosures are now commonly available in the market but make sure to use good quality 24V - 28V LED module with this circuit. During our prototype, we found a lot of defective LED modules in the market.

This is an open hardware project and all its source code are released under the terms of MIT license. Schematics, PCB designs, and other resources are released under the terms of Creative Commons Attribution 4.0 international license. All the source codes, design files and build instructions are at GitHub repository.

Comments

CD2003 - yet another simple FM radio receiver

In the last few days, we are looking for some simple FM radio receiver to integrate into one of our ongoing projects. For that, we try several FM radio receiver ICs including TDA7000, CD2003/TA2003/TA8164, CXA1019, and KA22429. Out of all those chips we select CD2003 (or TA2003/TA8164) based receiver for our project because of its simplicity and outstanding performance. Except to CD2003, Sony CXA1019 also perform well but we drop it because of its higher component count. We design our receiver based on Toshiba TA2003 datasheet and later we try TA8164 and CD2003 with the same circuit. Either CD2003 or TA8164 can directly replace TA2003 IC, and as per our observations, TA8164 gives excellent results out of those 3 chips. A prototype version of CD2003 FM radio receiver The PCB design and schematic which we used in our prototype project are available to download at google drive (including pin-outs of crystal filters and inductors ). Except for CD2003 IC, this receiver consist

Arduino superheterodyne receiver

In this project, we extend the shortwave superheterodyne receiver we developed a few years ago . Like the previous design, this receiver operates on the traditional superheterodyne principle. In this upgrade, we enhanced the local oscillator with Si5351 clock generator module and Arduino control circuit. Compared to the old design, this new receiver uses an improved version of an intermediate frequency amplifier with 3 I.F transformers. In this new design, we divide this receiver into several blocks, which include, mixer with a detector, a local oscillator, and an I.F amplifier. The I.F amplifier builds into one PCB. The filter stage, mixer, and detector stages place in another PCB. Prototype version of 455kHz I.F amplifier. In this prototype build, the Si5351 clock generator drives using an Arduino Uno board. With the given sketch, the user can tune and switch the shortwave meter bands using a rotary encoder. The supplied sketch support clock generation from 5205kHz (tuner frequ

Calculator for audio output transformers

Audio output transformers are heavily used in a vacuum tube and some (older) transistor base audio power amplifiers, but these days output transformer are quite hard to find and expensive item. For homebrew projects, the best option is to construct those transformers by ourselves and this script helps to calculate winding parameters for those transformers. This " AF output transformer calculator " script is written using Python and it works with most of the commonly available Python interpreters . The script is available to download at google drive under the terms of GNU General Public License version 3.0 . Homebrewed 25k: 4 output transformer Once supplied the input parameters this script provides a winding ratio, the number of turns required for primary and secondary winding and required copper wire gauges for both primary and secondary windings, etc. We construct several AF output transformers based on results of this script, which including transformers for M