Content for Charlieplexing

Charlieplexing

Charlieplexing is a technique for driving a multiplexed display in which relatively few I/O pins on a microcontroller are used e.g. to drive an array of LEDs. The method uses the tri-state logic capabilities of microcontrollers in order to gain efficiency over traditional multiplexing. Although it is more efficient in its use of I/O, there are issues that cause it to be more complicated to design and render it impractical for larger displays. These issues include duty cycle, current requirements and the forward voltages of the LEDs.

Using Pin Multiplexing to Reduce Pin Usage on 8-Bit Microcontrollers

“This post will cover two examples of using multiplexing on General Purpose Input/Output (GPIO) pins to reduce a project’s pin usage. The first example uses the technique “Charlieplexing” and the second uses timing peripherals and interrupts to quickly …

How to make simplest Arduino European Roulette Game

“Roulette is a casino game named after the French word meaning little wheel which was likely developed from the Italian game Biribi. In the game, a player may choose to place a bet on a single number, various groupings of …

Animated LED Sand

“Simulated Glowy Physics! These LEDs interact with motion and looks like they’re affect by gravity. An Adafruit LED matrix displays the LEDs as little grains of sand which are driven by sampling an accelerometer with an Adafruit Feather. The …

kitchen timer

“Here’s the bill of materials I ended up with: Teensy 2.0 Adafruit 16x9 Charlieplexed PWM LED Matrix Driver LED Charlieplexed Matrix - 9x16 LEDs - Warm White Rotary Encoder Solid Machined Metal Knob PowerBoost 500 Charger Lithium Ion Polymer Battery …

General Purpose Countdown Timer

“A general purpose countdown timer. Easily settable for up to one hour. Great for the kitchen. Perfect 5 minute eggs! In todays world of Apps for your smart phone, a countdown timer might seem like a bit of a redundant …

Animated Flame Pendant

“Turn on your heartlight Let it shine wherever you go Let it make a happy glow For all the world to see A little fire for your heart! But there’s no actual flame here, no heat…instead, LEDs and …

Development of ClockSquared Mini

“Summer break is here, and with some time to spare I decided to challenge myself with a project that I call “Clocksquared Mini”. It is Clocksquared, but in a tiny wristwatch package. This gives rise to a major challenge, as …

Animated Heart

“Just in time for Valentines day, a small gadget to be given to your sweetheart: a heart that loops through multiple animations. It nicely fits on a desk or table to have your loved one remember you! This animated heart …

Project  Charliewatch

Charliewatch

“”Analog” watch with 60+12 Charlieplexed LEDs. Based on Travis Goodspeed’s GoodWatch21 schematic, using the CC430F5137IRGZR CPU, which doesn’t have the LCD controller of the CC430F6xxx in the GoodWatch. There are also pads for a six pin EZfet …

Building a ‘papercraft’ LED marquee

“Long, dark winter nights demand some tinkering and crafts. Arduino LED projects are fun, but custom circuit boards might not always be in the budget. Thankfully, discrete LEDs can be found on Ebay for less than 1¢ apiece, and cardboard …