This project is a 7 segment LED display module that can be driven using SPI protocol, so it needs only 3 pins of your mcu to drive 4 x LED displays. It’s based on MAX7219 LED display driver.
Seven segment LED displays are very popular for displaying numeric information because they are very attractive and readable from a far distance and wider viewing angle.
The downside is they are resource-hungry. For example, it requires 12 I/O pins of a MCU to drive a 4-digit seven segment display using a standard time-division multiplexing technique.
Here I present a serial seven segment LED display module that can be used with any MCU using a 3-wire SPI interface. This particular display has four digits (0.40 size) and two colon segments (to support time display) display.
Serial 4-digit seven segment LED display - [Link]
Here is a very nice build of a LED heart that creates incredible animations. Check it out.
Today we present the perfect Valentine gadget: just shake it and it will turn on and crate incredible light animations. That will be cool for sure!
We know that, as it’s Valentine’s Day, looking at the device described in this post you’ll be inclined to think that this is the usual heart-shaped Valentine gadget: in reality this is something much cooler as it’s capable to create beautiful and complex light games. Is based on the smallest microcontroller manufactured by Atmel: the ATtiny85.
Hack your Valentine with HeartThrob - [Link]
John Kicklighter writes:
Watching fireflies is one my most memorable childhood events. Every summer, I would look forward to watching fireflies dance with their seemingly random blinks. I marveled at how a living creature could produce light all on its own. Even today as I share this experience with my children, I look forward to each season of fireflies.
TinyGlo was made to continue the experience of watching fireflies well after the firefly season has ended. Instead of having to wait another year to see them again, you can now bring the firefly like light show into your home and have a similar memorizing light show every evening.
TinyGlo – Your own firefly light show anytime - [Link]
Ray Wang writes about his project the SquareWear Mini with All-New Chainable Color LED Matrix, and an Interactive Animation Design Tool.
The goal is to make standalone programmable color display gadgets. The LED matrix is chainable and can be seamlessly extended in both X and Y directions. The SquareWear Mini is essentially an Arduino running at 3.3V and 12MHz. It plugs directly to the LED matrix, and has built-in USB port, temperature sensor, light sensor, buzzer, Lithium charger, and 16KB EEPROM. I wrote a software in Processing that communicates with SquareWear with HID Serial, and allows the user to interactively design pixel patterns and even animations with sound. Check the video and my blog post for details.
SquareWear Mini chainable color LED matrix and animation design tool - [Link]
This is a heart-shaped LED chaser would be a nice gift for Valentine’s Day. Circuit is very simple and uses the 555 timer IC (configured as astable multivibrator) and CD4017B decade counter.
The object of your desire will not be able to resist a heart-shaped LED chaser, lovingly hand-crafted on perfboard with a CD4017B decade counter and 555 astable. But you probably can’t go wrong with flowers and chocolates as well. Just to be on the safe side.
Heart-shaped LED chaser for Valentine’s Day - [Link]
Greeeg at the 430h forum has been working on a RGB LED ring clock:
The clock is comprised of 2 rings of 60 LEDs each. the LEDs are WS2812 parts, which include a built-in driver. The PCB is one of the interesting parts of this clock. I designed the board in altium as a single 6 LED segment. and then left pads at each end to allow them to be soldered onto another segment. Currently I am using a MSP-EXP430FR5739 board to drive it, using some very in-efficient assembly code that requires a 20MHz clock.
RGB LED ring clock - [Link]
Nick Leijenhorst build a 555 PWM circuit to dim his room LED lighting. He writes:
I wanted to dim my room LED lighting with a potentiometer, and decided on creating a solution from scratch to make it more fun and educative. I decided to go with the fairly well-known 555 PWM circuit. To decrease size and for learning purposes I decided on using surface-mount components for the first time. The reason I wanted to make this 555 PWM circuit is actually just to see if I could solder SMD components on home-etched PCB’s, and to see how hard it actually is.
Surface-mount 555 PWM circuit - [Link]
The PicoBuck is a small and inexpensive 3-channel LED driver. It employs constant-current buck driving which approaches an efficiency of 95% (theoretical). It’s based on AL8805 LED Lighting Buck Driver from Diodes Inc.
PicoBuck – RGB LED Driver - [Link]
Dilshan Jayakody wrote a post on his blog about his 3W constant current LED driver:
This is quick post about 3W constant current LED driver which I was design to combine with some homemade furniture piece. The main components of this system is LM311 voltage comparator and IRF9640 P-Channel MOSFET. This module is design to drive maximum of two 3W high power LEDs and it requires 8V – 10V DC (500mA) power source. In this given configuration this module may not need any heat-sink (for IRF9640) and consume maximum of 500mA of power.
DIY 3W constant current LED driver - [Link]
Dave Kruschke writes:
Yep, no transformer and no hard to get IC. But, … two transistors and other parts are required. I actually found this circuit by accident while roaming Colin Mitchell’s Talking Electronics website (talkingelectronics.com). This website is very rich with examples and explanations of a huge variety of circuits. In fact, this website is so abundant in circuits that later on, I couldn’t find the circuit revealed here. Anyhow, I believe that the TE circuit can be considered “robust” as it works even if different parts are used.
“Joule Thief” – no IC and no Transformer - [Link]