79 lines
1.8 KiB
Markdown
79 lines
1.8 KiB
Markdown
# Send Number
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Broadcasts a number data packet to other micro:bits connected via ``radio``.
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## Important Security Consideration
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The functions in the ``radio`` namespace allow the BBC micro:bit to communicate with other micro:bits.
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This API does not contain any form of encryption, authentication or authorization. It's purpose is solely for use as a teaching aid to demonstrate how simple communications operates, and to provide a sandpit through which learning can take place.
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For serious applications, BLE should be considered a substantially more secure alternative.
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```sig
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radio.sendNumber(0)
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```
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### Parameters
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* packet - a number to be transmitted.
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### Examples
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Broadcasts the value of ``acceleration`` x to other micro:bits.
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```blocks
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input.onButtonPressed(Button.A, () => {
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radio.sendNumber(input.acceleration(Dimension.X))
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})
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```
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### Light level sender
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This example broadcasts the level of the light around it:
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```blocks
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radio.setGroup(99)
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basic.forever(() => {
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let level = input.lightLevel()
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radio.sendNumber(level)
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})
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```
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This example shows the light level from the sender (above):
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```blocks
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radio.setGroup(99)
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basic.forever(() => {
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let level = radio.receiveNumber()
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basic.showNumber(level)
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})
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```
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### Mailbot
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This example takes the signal from the light level sender (above)
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and shows a text string if the light level becomes much brighter.
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You can put the light level sender in your mailbox and it will
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tell you when someone opens the box. You can try this with a normal
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box too, like a present.
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```blocks
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radio.setGroup(99)
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let max = 0
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basic.forever(() => {
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let level = radio.receiveNumber()
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if (level > max) {
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let max = level
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}
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if (max > 10) {
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basic.showString("ALERT")
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}
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})
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```
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### See also
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[receive number](/reference/radio/receive-number), [on data received](/reference/radio/on-data-received)
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