What is Time-of-flight (ToF)?

Time-of-flight (ToF) is like when you shout to a friend across a room and count how long it takes for them to reply.

Imagine you're playing hide-and-seek. You yell, "Ready or not, here I come!" and then you start counting: 1, 2, 3... The longer it takes for your friend to answer, the farther away they are. That’s how ToF works, it measures how long something takes to travel from one place to another.

How It Works

Think of a ping-pong ball being thrown from one side of the room to the other. If the room is small, the ball gets there quickly. If it's big, it takes longer. ToF uses this idea: it sends out something, like light or sound, and measures how long it takes for that something to come back.

Why We Use It

ToF helps us know how far away things are. It’s used in robots, phones, and even video games! Just like you use your voice to find a friend in hide-and-seek, ToF uses time to find where things are, fast and fun!

Take the quiz →

Examples

  1. A ToF sensor in a smartphone measures how long it takes for a flash of light to bounce back from your face.
  2. Using sound, a car's parking sensor calculates the distance to an object by timing how long it takes for the echo to return.
  3. A simple ToF meter uses a laser and clock to measure how far away a target is.

Ask a question

See also

Discussion

Recent activity