You have one day to make a halloween decoration! What will you do!? Well, if you have a Trinket and a couple of LEDs + a photo cell you can build these randomly blinky eyes that turn on when it gets dark
A recent MAKE project, Spooky Blinky Eyes by Bill Blumenthal, demonstrates an ATTiny45 processor fading a pair of LED eyes that randomly blink, giving a more realistic effect than standard “always on” LED eyes.
The effect is due to come clever programming of the timers available on the ATTiny processors featured on the Adafruit Trinket and Gemma microcontrollers. Pins 0 and 1 are capable of pulse width modulation. The timers are set to fade the pins in and out by changing the pulse width back and forth. The blink effect is using an algorithm called a linear feedback shift register (LFSR) to pseudo-randomly turn the eyes off and on quickly.
This project adapts the original code for use on the faster ATTiny85 processor and for the Arduino integrated development environment (IDE). It also adds a Cadmium Sulfide (CdS) photocell to allow the eyes to come on only below a certain light level. During sunlight, this will save battery power.
Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.
Join us every Wednesday night at 8pm ET for Ask an Engineer!
Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground” – Adafruit’s Apps!
Maker Business — “Silicon Valley startups invade Best Buy”
Wearables — Bringing cosplay to life
Electronics — Is your op amp going crazy?
Biohacking — mPort is Making a 3D Body Scanner Booth
No comments yet.
Sorry, the comment form is closed at this time.