EV3 Robotics›Component tutorials›Sound and beeps

Output · Level 1 · 5 min

Sound and beeps

Play a sound or a beep, and choose whether the program waits for it.

ComponentOutput5 min

Sound and beeps

The Brick has a small speaker. It can play one of the built-in sound files, or beep a note you choose. Sound is what makes a machine feel finished — and it is also a way for the robot to tell you something without you having to look at it.

EV3 Intelligent Brick from the side, showing the speaker grille
The speaker is in the side of the Brick. It is the one output a person notices without looking at the robot.

Blocks reference

BlockWhat it does
play sound [Communication / Hello v] until done :: sound
Plays the sound and waits for it to finish before the next block runs.
start sound [Communication / Hello v] :: sound
Starts the sound and moves straight on to the next block, so the sound plays while the robot keeps working.
play beep (60) for (0.5) seconds :: sound
Plays a single note for a set time — useful for short alerts. The number is a note, not a volume: bigger means higher.
set volume to (100) % :: sound
Sets how loud everything after it will be. Worth putting at the top of a program — the Brick remembers the last volume it was given, even from somebody else’s program.
stop all sounds :: sound
Cuts off anything that is still playing, including a long sound started earlier.

Wait for it, or not

These two blocks play the very same file. The difference is what the rest of the program does while it plays — so it cannot be heard on its own, only seen. Here are both, each lifting a barrier.

play sound until done

when program starts
play sound Communication / Hello until done
A run clockwise for 1 rotations

start sound

start sound Communication / Hello
A run clockwise for 1 rotations
0.0suntil done0.0sstart sound
until done: warn first, then movestart sound: warn while moving
Two programs. Same sound, same movement — only the sound block is different.
stopped

Watch the barriers, not the clock. On the left the warning finishes before anything moves; on the right it sounds while the barrier lifts.

The bars underneath are when the speaker was on and when the motor was turning. On the left they never overlap: the program is stuck at the sound block until the file has finished, and only then does the barrier lift. On the right they overlap almost completely, and the whole job is done in half the time.

  • play sound until done — everything stops and waits. Use it for a warning that must be heard before something moves.
  • start sound — the sound and the movement happen together. Use it when the noise belongs to the movement, like a motor whirring as an arm lifts.

Why it matters

Real machines warn before they move, not after: a lift chimes before the doors close, a reversing lorry beeps while it rolls back, a level crossing sounds before the barrier drops. Getting the order right is the difference between a warning and an apology.

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