Merge branch 'master' of https://github.com/Microsoft/pxt-microbit into setpull

This commit is contained in:
Peli de Halleux 2016-06-03 10:35:05 -07:00
commit 45690215dd
3 changed files with 31 additions and 27 deletions

View File

@ -147,6 +147,13 @@ input.onButtonPressed(Button.A, () => {
});
```
#### ~hint
The ``showString`` block can show letters, numbers, and punctuation
on the micro:bit screen.
#### ~
Now try to unscramble these blocks in the editor so that the micro:bit
shows **banana** when you press button `B`.
@ -160,10 +167,13 @@ input.onButtonPressed(Button.B, () => {
You can find the letter `B` by clicking the letter `A` on the
``onButtonPressed`` block.
####
#### ~
Can you combine these blocks so your program shows **anteater** when
you press `A`, but **banana** when you press `B`?
#### Your turn!
Can you combine these blocks so your program shows your real name
instead of **anteater** when you press `A`, but _your secret agent
name_ instead of **banana** when you press `B`?
### Shake

View File

@ -5,14 +5,14 @@ Run part of a program when the micro:bit receives a
### Parameters
* **body** is the part of the program to run when the micro:bit receives information over ``radio``.
* the part of the program to run when the micro:bit receives information over ``radio``.
### Example
This program never stops. It keeps sending numbers that says how
fast the micro:bit is slowing down or speeding up. It also receives
numbers that say how fast nearby micro:bits are going. It
shows these numbers as a [bar graph](/reference/led/plot-bar-graph).
This program keeps sending numbers that says how fast the micro:bit is
slowing down or speeding up. It also receives numbers for the same
thing from nearby micro:bits. It shows these numbers as a
[bar graph](/reference/led/plot-bar-graph).
```blocks
basic.forever(() => {

View File

@ -1,33 +1,27 @@
# Set Transmit Power
Sets the transmitter power for ``radio`` communications.
The power can be set to a value between 0 (-30dbm) and 7 (+4dbm).
Make the ``radio`` signal of the micro:bit stronger or weaker.
It can be as weak as `0` and as strong as `7`.
The scientific name for the strength of the ``radio`` signal is
**dBm**, or **decibel-milliwatts**. A signal strength of `0`
can be measured as -30 dBm, and a strength of `7` can be
measured as +4 dBm.
## Range
At power level 7, in an open area without significant interference (coming from WiFi networks or other devices operating on the 2.4 GHz range), you can get a **range of over 70m**.
Indoors (or with additional interference), range will be significantly reduced.
## 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.setTransmitPower(1)
```
If your micro:bit is sending with a strength of `7`, and you are in
an open area without many other computers around, the micro:bit signal
can reach as far as 70 meters (about 230 feet).
### Parameters
* ``power`` -- a [number](/reference/types/number) between ``0`` and ``7``.
* a [number](/reference/types/number) between ``0`` and ``7`` that
means how strong the signal is.
### Example
Sets the transmitter power to full power at 7.
This program makes the ``radio`` send at full strength.
```blocks
radio.setTransmitPower(7)