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# Send data to the computer
micro:bit and the computer · Talk over USB
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## Today
**We are learning to** a micro:bit sends each sensor reading down the USB cable as a line of text, such as light:128. The computer turns the stream of lines into a graph.
- I can send a sensor reading to the computer again and again.
- I can explain what travels down the cable (a named line of text).
- I can send two values and choose how often they are sent.
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## Why it matters
> Weather stations, heart-rate monitors and the sensors in a science lab all do the same simple thing: send a reading, wait, send the next. A computer collects the readings and draws the graph.
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💬 Discussion
## Predict
**This program runs on a micro:bit plugged into a computer. What arrives at the computer every half second?**
- A picture of the LEDs
- Just the number 128
- A line of text, such as light:128
- A graph
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✅ Check
## What happened?
* A line of text: the name light, a colon, and the reading. The computer draws the graph from the lines; the micro:bit only sends text.
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✍️ Activity
## Run it
Open the lesson at this step and try it together.
[studio.learningwaypoints.com/tutorials/code/microbit-computer/send-data/?full=step-2#step-2](https://studio.learningwaypoints.com/tutorials/code/microbit-computer/send-data/?full=step-2#step-2)
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✍️ Activity
## Run it
{{embed: https://studio.learningwaypoints.com/tutorials/_playground-board/index.html?id=deck%2Fcode%2Fmicrobit-computer%2Fsend-data%2Fstep-3&code=widget%3A+serial%0Awindow%3A+20%0A&fresh=1}}
[Open this step in the tutorial](https://studio.learningwaypoints.com/tutorials/code/microbit-computer/send-data/?full=step-3#step-3)
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💬 Discussion
## Investigate
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✅ Check
## Names
**Why does each line start with a name (light:)?**
- To make the number bigger
- So the micro:bit remembers it
- The cable needs a name to work
- So the computer can tell different values apart when there are several
* Answer: So the computer can tell different values apart when there are several
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✅ Check
## No pause
**You delete the pause. What happens?**
- One reading is sent, then it stops
- Nothing is sent
- The readings get more accurate
- Readings pour out as fast as the micro:bit can send them, far more than you need
* Answer: Readings pour out as fast as the micro:bit can send them, far more than you need
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✅ Check
## Ben's logger
Ben's program:
**Ben's program sends one reading when the micro:bit starts, then nothing. Why?**
- Light level only works once
- The board can only read one line
- The cable is broken
- The block is in on start, not in forever, so it runs only once
* Answer: The block is in on start, not in forever, so it runs only once
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✍️ Activity
## Modify
- **Two values:** Send the **temperature** too, with its own name. In Show data (or on the board), each name gets its own line.
- **Faster:** Make it send **ten readings a second**.
[Open this step](https://studio.learningwaypoints.com/tutorials/code/microbit-computer/send-data/?full=step-5#step-5)
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✍️ Activity
## Make
Make a **tilt logger**: send the micro:bit's **x** and **y** acceleration five times a second, and send the line **mark** when **A** is pressed, so you can mark a moment on the record. Tilt it in the simulator and watch Show data.
[Open this step](https://studio.learningwaypoints.com/tutorials/code/microbit-computer/send-data/?full=step-6#step-6)
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✅ Check
## Exit ticket
**What does the computer receive when the micro:bit runs serial write value light, light level?**
* A line of text: the name light, a colon and the reading, such as light:128.