Digital Sandbox Experiment Guide
jimblom, 
bri_huang 
2: Multi-Blink
Large arrays of LEDs are often used to create massive outdoor signs and animations because they're both bright and efficient. While we don't have the millions of LED pixels that a display in Times Square might have, we can still create some fun patterns with the Digital Sandbox.
Background Information
In this experiment we explore the subject of pins -- the manipulators of the Sandbox. Each LED (as well as the other inputs and outputs on the Digital Sandbox) is connected to a specific pin on the Sandbox's microcontroller.
Pins are all uniquely numbered, and each input or output component on the Sandbox is labeled with the pin number it's connected to -- that's the D2, D4, D11, A1, etc. lettering next to each LED, switch and sensor.
Every pin can be separately controlled; for instance pin 4 can be set HIGH at the same time pin 5 is set LOW. Some pins (as we'll later discover) have special powers, but every pin is at least able to accomplish digital input and output.
Active Parts
Code Components
Whoa! Block explosion! This experiment calls for sixteen total blocks:
Instead of introducing a new block, we'll be adjusting the value of Set Digital Pin's top pin - the pin number. This value specifies which of the Sandbox's pins we'll be toggling.
Do This
In our unfinished example, the blocks are all arranged in groups of three. Each group begins by setting a pin HIGH, then delays for a second and sets it back to LOW. Notice that each group of three toggles a different pin, ranging from pin 4 to pin 8. Stack the groups-of-three on top of each other in the loop, then upload and enjoy the exciting animation.
If the LED slide is too slow for you, try adjusting the delays to make it faster, or perhaps you want to change the pins to adjust the order of the blinks.
Further Explorations
- Try adding more blocks to create slicker patterns. Can you make a Larson scanner (ask an old person about Cylons or Knight Rider)? A chaser? Flip from odds to evens?
- Try turning on more than one LED at a time. Turn them all on (and shield your eyes)!