This is a very basic power failure lighting circuit based around a relay.
This simple circuit has many uses, from lighting up rooms and walkways in the case of a power failure, to monitoring and security uses.
There are many different power failure circuits out there based on 555 timers or transistors but they all have different problems including limited input voltage, price and complexity, and poor backup power. This unit has been designed to work with mains power all the way down to 5 volts, and power 3 LEDs to provide light for a hallway or a child’s room in the event of power failure. The PCB includes many simple add-ons and modifications too.
A Very Simple Power Failure Light - [Link]
This article shows how to make a DIY Infrared illuminator to help Night Viewing of Your Camera. The IR Illuminator allows a camera to see in total darkness.
The IR Illuminator is based around our LED SpotLight PCB which holds a total of 24 LEDs on a circular PCB. The board is equipped with 24 special IR LEDs which do all of the work, along with 8 current limiting resistors. This project is very simple to build up, and can be fully assembled by a novice builder in about 30 minutes.
DIY Infrared Illuminator - [Link]
This circuit is a supply voltage monitor which uses a LED to show the status of a power supply.
This simple and slightly odd circuit can clearly show the level of the supply voltage (in a larger device): as long as the indicator has good 12 volts at its input, LED1 gives steady, uninterrupted (for the naked eye) yellow light. If the input voltage falls below 11 V, LED1 will start to blink and the blinking will just get slower and slower if the voltage drops further – giving very clear and intuitive representation of the supply’s status. The blinking will stop and LED1 will finally go out at a little below 9 volts.
Supply Voltage Indicator – [Link]
The device comprises two parts: LED control board and LED display board. The two PCBs are designed to fit together one behind the other using two sets of dual row connectors and 4 spacers. One of this connector is used for the electrical connections, while the other is only used as a mechanical connecting element.
Dot matrix LED running display - [Link]
This project shows how to build a Digital clock with 32×8 LED matrix display based on ATmega168 microcontroller. It doesn’t use a RTC timer chip but timer interrupt triggered via external crystal at 32.678kHz. It allows generating exact 1sec intervals while AVR is running with internal system clock at 8MHz.
Digital clock with 32×8 LED matrix display - [Link]
The 555 Astable generates a clock for this circuit, an oscillator giving a square wave output at pin 3 which is counted by 4017 to give a running lights effect.
The decade counter-divider CD4017 has 10 outputs, for every low to high transition at the clock input, rising edge, the counter advances one LED. After going one full circle the the first LED lights again and it goes on. You can vary the value of R2 100K Linear potentiometer to make LEDs run fast or slow.
Running Lights with CD4017 - [Link]
RGB LED game to play Tic-Tac-Toe for two players. Uses 2 AVR Microcontrollers: Mega16 and Mega8. RGB LEDs allow each user to choose his/her color to represent Cross/Nut.
Electronic Tic-Tac-Toe with RGB LEDs - [Link]
This project shows how to build a rechargeable led flashlight powered by magnets and housed in a mints container. Check details on the link below.
Rechargable LED Flashlight - [Link]
This is a simple LED torch circuit based on IC MAX660 from MAXIM semiconductors. The MAX 660 is a CMOS type monolithic type voltage converter IC. The IC can easily drive three extra bright white LEDs. The LEDs are connected in parallel to the output pin 8 of the IC. The circuit has good battery life. The switch S1 can be a push to ON switch.
LED torch using MAX660 - [Link]
I’ve always wanted to build an electronic led dice, but something different from what we see on the internet. Making it motion controlled… now that’s new! Many new cell phones that have accelerometers built in also have dice games. These dice move when shaking the cell phone. My Led Dice project will also work with a shake motion but without the use of the expensive accelerometers.
Motion Activated Led Dice - [Link]