adding lessons to create circuit using aluminium foil

docs/device/crocodile-clips.md

@@ -1,11 +1,40 @@
 # crocodile clips
 
-The large holes at the bottom of the board are designed to attach alligator/crocodile clips.
+The large holes at the bottom of the board are designed to attach alligator/crocodile clips 
-Register an event that will execute whenever the user attaches one side of the crocodile clip to the `GND` pin, then connects and disconnects the unattached side of the crocodile clip to pin `0`, `1`, or `2`.
+to create electrical circuit with other components.
 
-### Example: on pin pressed with random numbers
+# ~hint
 
-This example displays a random number every time the crocodile clip holds  `GND` then connects and disconnects the `P0` pin. Each time the crocodile clip is firmly connected and disconnected from pin `P0`, the micro:bit will return a random Number between 0 and the parameter limit
+**No crocodile clips!?!?!** Use wires or Aluminium foil! [Read more...](/device/foil-circuits)
+
+# ~
+
+
+## Connecting Crocodile Clips
+
+The hole for ``P0`` and ``GND`` allow to grab the board on the side which makes for a great grip.
+
+![](/static/mb/device/croc-clips/crocclipsclamped.jpg)
+
+Pass one jaw in the hole and grab the side of the board with the other jaw.
+
+![](/static/mb/device/croc-clips/sideclamp.jpg)
+
+For the center holes, ``P1`` and ``P2``, you can also grab the bottom of the board but they are a bit harder to grip.
+
+You can also grip the board between the jaws. In which case, you will want to make sure to avoid overlapping the jaws 
+with the other pins as it will create short-circuit in the board.
+
+![](/static/mb/device/croc-clips/badclamp.jpg)
+
+Adding a little tape helps keeping the crocodile clips in place.
+
+![](/static/mb/device/croc-clips/frontclamp.jpg)
+
+## Example: on pin pressed with random numbers
+
+This example displays a random number every time the crocodile clip holds  `GND` then connects and disconnects the `P0` pin. 
+Each time the crocodile clip is firmly connected and disconnected from pin `P0`, the micro:bit will return a random Number between 0 and the parameter limit.
 
 ```blocks
 input.onPinPressed(TouchPin.P0, () => {
@@ -13,11 +42,6 @@ input.onPinPressed(TouchPin.P0, () => {
 })
 ```
 
-### Connecting Crocodile Clips
+## See also
-
-![](/static/mb/crocodile-clips-2.jpg)
-
-### See also
-
-[micro:bit pins](/device/pins), [pin is pressed](/reference/input/pin-is-pressed), [analog read pin](/reference/pins/analog-read-pin), [analog write pin](/reference/pins/analog-write-pin), [digital read pin](/reference/pins/digital-read-pin), [digital write pin](/reference/pins/digital-write-pin)
 
+[micro:bit pins](/device/pins)

docs/device/error-codes.md

@@ -1,7 +1,5 @@
 # Error codes
 
-The micro:bit error codes
-
 Your micro:bit may encounter a situation that prevents it from running your code. When this happens, a frowny face will appear on your micro:bit screen (see picture) followed by an error number.
 
 Below is a list of error numbers and what they mean:

docs/device/foil-circuits.md

@@ -0,0 +1,52 @@
+# foil circuits
+
+The large holes at the bottom of the board are designed to attach alligator/crocodile clips 
+to create electrical circuit with other components.
+
+If you do not have crocodile clips at hand, dyou can use wires or even Aluminium foil to acheive the same result.
+We will show you how to connect the micro:bit to headphones using Alumunium foil and tape.
+
+https://youtu.be/mhXYyPuvpz0
+
+### Materials
+
+* micro:bit and battery pack (you can also power it via USB)
+* a small piece of cardboard
+* Aluminium foil
+* tape
+
+### Assembly instructions
+
+Tape the micro:bit and battery pack to the card board. Make sure to remove the batteries while you are building your circuit.
+
+![](/static/mb/device/croc-clips/microbitattached.jpg)
+
+Cut the thinest strip of foil possible and roll it into a cable. You can also try to fold, whatever works for you.
+Build two of those wires.
+
+![](/static/mb/device/croc-clips/foilcut.jpg)
+
+Place the foil wire on the ``GND`` pin and attach with a piece of tape. Press hard to get the best connection between
+the foil and the pin board. Make sure the foil is not overlapping with the other pins!
+
+![](/static/mb/device/croc-clips/groundconnected.jpg)
+
+Place the second wire on the ``P0`` pin the same way. Make sure the wire does not overlap with the other pins!
+
+![](/static/mb/device/croc-clips/microbitconnect.jpg)
+
+Tape the headphone jack connector to the cardboard and roll the wire coming from ``GND`` around the metal base. 
+Make sure the wire does not touch the other metal rings on the jack.
+
+![](/static/mb/device/croc-clips/jackground.jpg)
+
+Tape the second wire on the head of the jack connector.
+
+![](/static/mb/device/croc-clips/jackconnect.jpg)
+
+![](/static/mb/device/croc-clips/foilcircuit.jpg)
+
+
+## See also
+
+[micro:bit pins](/device/pins)

docs/projects/hack-your-headphones.md

@@ -24,6 +24,12 @@ Build your own music player micro:bit from headphones.
 * [Connect your headphone](/projects/hack-your-headphone/making)
 * [Play sounds!]()
 
+# ~hint
+
+**No crocodile clips!?!?!** Use wires or Aluminium foil! [Read more...](/device/foil-circuits)
+
+# ~
+
 ### ~button /projects/hack-your-headphones/making
 
 Let's get started!

docs/projects/hack-your-headphones/making.md

@@ -6,6 +6,12 @@ Did you know you could attach your headhpones to the micro:bit to generate sound
 
 ### ~
 
+# ~hint
+
+**No crocodile clips!?!?!** Use wires or Aluminium foil! [Read more...](/device/foil-circuits)
+
+# ~
+
 ### Step 1
 
 ![](/static/mb/lessons/banana-keyboard-1.png)