pxt-calliope/docs/reference/radio/receive-string.md

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2016-05-25 03:23:33 +02:00
# Receive String
Reads the next radio packet if any and returns the first string.
## Important Security Consideration
The functions in the ``radio`` namespace allow the BBC micro:bit to communicate with other micro:bits.
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.
For serious applications, BLE should be considered a substantially more secure alternative.
```sig
radio.receiveString()
```
### Return value
* the first [string](/reference/types/string) of the packet if any. ```""``` otherwise.
### Examples
Read the string broadcasted by other micro:bits and display it.
```blocks
radio.onDataReceived(() => {
basic.showString(radio.receiveString());
});
```
A simple program to send whether you are happy, or sad over ```radio```, using the A or B button to select an emotion.
```blocks
let data: string = "";
input.onButtonPressed(Button.A, () => {
radio.sendString("H");
});
input.onButtonPressed(Button.B, () => {
radio.sendString("S");
});
radio.onDataReceived(() => {
data = radio.receiveString();
if ("H" == data) {
basic.showLeds(`
. . . . .
. # . # .
. . . . .
# . . . #
. # # # .
`);
} else if ("S" == data) {
basic.showLeds(`
. . . . .
. # . # .
. . . . .
. # # # .
# . . . #
`);
} else {
basic.showString("?");
}
});
```
### See also
[send string](/reference/input/send-string), [on data received](/reference/radio/on-data-received)