added voting project

docs/examples/radio-dashboard.md

@@ -15,9 +15,8 @@
  * 
  * If the radio packet is not received for 10sec, the LED starts blinking.
  */
-
+const deadPing = 20000;
 const lostPing = 10000;
-const group = 4;
 
 interface Client {
     // client serial id
@@ -59,7 +58,7 @@ radio.onDataPacketReceived(packet => {
         return;
 
     client.ping = input.runningTime()
-    client.sprite.setBrightness(packet.receivedNumber & 0xff);
+    client.sprite.setBrightness(Math.max(1, packet.receivedNumber & 0xff));
 })
 
 // monitor the sprites and start blinking when no packet is received
@@ -67,15 +66,20 @@ basic.forever(() => {
     const now = input.runningTime()
     for (const client of clients) {
         // lost signal starts blinking
-        if (now - client.ping > lostPing)
+        const lastPing = now - client.ping;
+        if (lastPing > deadPing) {
+            client.sprite.setBlink(0)
+            client.sprite.setBrightness(0)
+        }
+        else if (lastPing > lostPing)
             client.sprite.setBlink(500);
-        else client.sprite.setBlink(0);
+        else
+            client.sprite.setBlink(0);
     }
     basic.pause(500)
 })
 
 // setup the radio and start!
-radio.setGroup(group)
-radio.setTransmitPower(6)
-radio.setTransmitSerialNumber(true)
+radio.setGroup(4)
+game.addScore(1)
 ```

docs/projects.md

@@ -39,6 +39,10 @@ Fun games to build with your @boardname@.
   "name": "Infection",
   "url": "/projects/infection",
   "imageUrl": "/static/mb/projects/infection.png"
+}, {
+  "name": "Voting Machine",
+  "url": "/projects/voting-machine",
+  "imageUrl": "/static/mb/projects/voting-machine.png"
 }]
 ```
 

docs/projects/voting-machine.md

@@ -0,0 +1,77 @@
+# Voting Machine
+
+### ~ avatar
+
+Build a vote collection system using many micro:bit!
+
+### ~
+
+https://youtu.be/77HOqf8BaNg
+
+
+In this project, a **voter** program is uploaded on the player's @boardname@. The player uses the buttons to vote yes or no 
+and the vote sent to the **dashboard** @boardname@ via radio. The dashboard allocates one LED per player and turns it on for "yes" and off for "no".
+
+Both programs set their radio group to ``4`` to be able to communicate.
+
+## The voter program
+
+Assuming button ``A`` is no and ``B`` is yes, the voter program works as follows:
+
+* when button ``A`` is pressed, a number ``0`` is sent via radio and the ``X`` symbol is shown on the screen.
+
+```block
+input.onButtonPressed(Button.A, () => {
+    radio.sendNumber(0)
+    basic.showIcon(IconNames.No)
+})
+```
+
+* when button ``B`` is pressed, a number ``255`` is sent via radio and the ``Y`` symbol is shown on the screen.
+
+```block
+input.onButtonPressed(Button.B, () => {
+    radio.sendNumber(255)
+    basic.showIcon(IconNames.Yes)
+})
+```
+
+* In order to track the votes, we tell the radio to also transmit the device serial number.
+
+```block
+radio.setTransmitSerialNumber(true)
+```
+
+* we arbritrarily choose ``4`` as the group used for the communications
+
+```block
+radio.setGroup(4)
+```
+
+Combined together, the voter program looks as follows:
+
+```blocks
+input.onButtonPressed(Button.A, () => {
+    radio.sendNumber(0)
+    basic.showIcon(IconNames.No)
+})
+input.onButtonPressed(Button.B, () => {
+    radio.sendNumber(255)
+    basic.showIcon(IconNames.Yes)
+})
+radio.setGroup(4)
+radio.setTransmitSerialNumber(true)
+basic.showIcon(IconNames.Ghost)
+```
+
+## The dashboard
+
+The dashboard code can be found at [/examples/radio-dashboard](/examples/radio-dashboard).
+
+Download the code from that example into the @boardname@ that will be used to display the result.
+
+When the dashboard receives a message from a @boardname@, it find a pixel for that board (and remembers it)
+and uses the number received as the brightness of the LED.
+
+When a message hasn't been received by a board for some time, it's pixel will start to blink. After more time, it will simply turn off. 
+