Communication Device Builder
Pick a flashlight, drum, or cup phone, then design a pattern of pulses to send a message. Watch and listen to what the receiver picks up. Learn how light, sound, and vibration carry signals over distance.
Score: 0
Choose your device
Flashlight. Shine pulses of light to send messages far away. Range: Across a dark room.
Light receiver
Pattern length5
Tap each cell to turn the signal on or off.
Receiver hears: 1 flash, pause, 1 flash, pause, 1 flash
That is the pattern for "Hello"
Try a preset message
Reference Guide
How Devices Send Messages
- Flashlight. Sends flashes of light. Light travels very fast and works best in dark places.
- Drum. Makes loud beats. Sound travels through the air as invisible waves.
- Cup Phone. Two paper cups joined by string. Your voice shakes the bottom of one cup, and that shaking travels as vibration along the string to the other cup.
- Pattern. The order of pulses and pauses is what carries meaning.
Light, Sound, and Vibration
- Light travels in straight lines and moves very fast.
- Sound is a vibration that spreads through air, water, or solid objects.
- Vibration is a tiny back and forth wiggle that can carry a signal.
- People can plan patterns so others understand the message.
- Standard covered. 1-PS4-4.
Example Patterns
- Hello. Three quick pulses. Works on any device.
- Come Here. Two pulses, a pause, then two more.
- SOS. Three short, three long, three short. A famous call for help sent by flashlights or drums.
- Yes. Two quick pulses. Best for drums and cup phones.
- No. Three pulses in a row. Easy to drum or tap.
Try This
- Design your own pattern and tell a friend what it means.
- Try sending the same message with two different devices. Which travels farthest?
- Switch to Challenge mode. Match the target message exactly.
- Long signals feel different from short ones. Plan your pattern so the receiver can tell them apart.
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Related Labs
Communication Device Lab
Investigate how light patterns, drum beats, and cup-phone vibrations send messages over distance. Record patterns and decode signals across three device types. Grades K-1.
Light, Shadows & Materials Lab
Investigate how transparent, translucent, and opaque materials change the shadows they cast. Record shadow strength for glass, water, wood, fabric, and more. Grades K-1.
Pushes & Motion Lab
Apply pushes and pulls to different objects and observe how force type, strength, and direction change motion. Collect data and discover Newton's laws in action. Grades K-2.
Waves & Secret Messages Lab
Explore wave amplitude and wavelength, discover which materials waves travel through, and decode secret flash-code messages. NGSS 4-PS4-3. Grades 3–5.
