fix more broken links

docs/reference/input/acceleration.md

@@ -38,5 +38,5 @@ basic.forever(() => {
 
 ### See also
 
-[compass-heading](/reference/input/compass-heading), [lightlevel](/reference/input/lightlevel)
+[compass-heading](/reference/input/compass-heading), [lightlevel](/reference/input/light-level)
 

docs/reference/music/play-tone.md

@@ -27,5 +27,6 @@ music.playTone(freq, 1000)
 
 ### See also
 
-[rest](/reference/music/rest), [ring tone](/reference/music/ring-tone) , [tempo](/reference/music/tempo), [set tempo](/reference/music/set-tempo), [change tempo by](/reference/music/change-tempo-by)
+[rest](/reference/music/rest), [ring tone](/reference/music/ring-tone) , [tempo](/reference/music/tempo), [set tempo](/reference/music/set-tempo), 
+[change tempo by](/reference/music/change-tempo-by)
 

docs/reference/radio/send-value.md

@@ -0,0 +1,29 @@
+# Send Number
+
+Broadcast a (name,number) pair to other micro:bits connected via ``radio``.
+
+### Parameters
+
+* name - a string to send
+* num - a number to send.
+
+### Simulator
+
+This function only works on the micro:bit, not in browsers.
+
+### Example: Broadcasting acceleration
+
+This example broadcasts the value of your micro:bit's ``acceleration`` in the `x` direction 
+(left and right) to other micro:bits.
+This kind of program might be useful in a model car or model rocket.
+
+```blocks
+input.onButtonPressed(Button.A, () => {
+    radio.sendValue("acc",input.acceleration(Dimension.X))
+})
+```
+
+### See also
+
+[receive number](/reference/radio/receive-number), [on data received](/reference/radio/on-data-received)
+