Plant watering system (#419)

* added youtube movie

* plant watering system

* added project entry

docs/SUMMARY.md

@@ -20,6 +20,7 @@
     * [Duct tape wallet](/projects/wallet)
     * [Watch](/projects/watch)
     * [Soil Moisture](/projects/soil-moisture)
+    * [Plant Watering](/projects/plant-watering)
     * [Voting Machine](/projects/voting-machine)
     * [Infection](/projects/infection)
     * [Fireflies](/projects/fireflies)

docs/projects.md

@@ -111,6 +111,10 @@ Fun games to build with your @boardname@.
   "name": "Soil Moisture",
   "url":"/projects/soil-moisture",
   "imageUrl":"/static/mb/projects/soil-moisture.jpg"
+}, {
+  "name": "Plant Watering",
+  "url":"/projects/plant-watering",
+  "imageUrl":"/static/mb/projects/plant-watering.jpg"
 }]
 ```
 

docs/projects/plant-watering.md

@@ -0,0 +1,40 @@
+# Plant Watering
+
+
+### ~avatar avatar
+
+Water your plants automatically!
+
+### ~
+
+https://youtu.be/7eC_VjH1eP0
+
+### ~ hint
+
+This is a follow up of the **[soil moisture project](/projects/soil-moisture)**.
+
+### ~
+
+## Materials
+
+* 1 @boardname@ with battery pack and batteries
+* 2 long nails or silver
+* 2 crocodile clips
+* 1 micro servo  + 3 female-to-croc clips
+* 1 ice cream wooden stick
+* 2 elastics
+* 1 clear tape roll
+* 1 straw
+* 1 pair of scissors
+
+## Activities
+
+* [Make](/projects/plant-watering/make)  
+* [Code](/projects/plant-watering/code)
+* [Connect](/projects/plant-watering/connect)
+
+### ~button /projects/plant-watering/make
+
+Let's get started!
+
+### ~

docs/projects/plant-watering/code.md

@@ -0,0 +1,59 @@
+# Code
+
+Let's add the code so that _when the soil moisture level is low, the servo waters the plant._
+
+From the **soil moisture** project, we know that the moisture is low when the ``reading`` is roughly less than ``500``.
+We can use this information to add an ``if reading < 500`` in the code.
+
+```block
+let reading = 0
+if (reading < 500) { }
+```
+
+The servo is connected to pin ``P2`` so we can use ``pins servo write`` block to change the angle of the servo.
+We need it to change the angle to ``0``, wait until the water has fallen off, and move it back to ``80``.
+
+```block
+let reading = 0
+if (reading < 500) {
+    basic.showIcon(IconNames.Umbrella)
+    pins.servoWritePin(AnalogPin.P2, 0);
+    basic.pause(3000)
+    pins.servoWritePin(AnalogPin.P2, 80)
+    basic.pause(3000)
+    pins.analogWritePin(AnalogPin.P2, 0)
+}
+```
+
+We insert the code above in the **forever** loop of the [soil moisture code](/projects/soil-moisture/connect).
+
+```blocks
+radio.setTransmitSerialNumber(true)
+radio.setGroup(4)
+led.setBrightness(64)
+let reading = 0
+basic.forever(() => {
+    pins.analogWritePin(AnalogPin.P1, 1023)
+    reading = pins.analogReadPin(AnalogPin.P0)
+    radio.sendNumber(reading / 4);
+    pins.analogWritePin(AnalogPin.P1, 0)
+    led.plotBarGraph(
+        reading,
+        1023
+    )
+    if (input.buttonIsPressed(Button.A)) {
+        basic.showNumber(reading)
+    }
+    if (reading < 500) {
+        basic.showIcon(IconNames.Umbrella)
+        pins.servoWritePin(AnalogPin.P2, 0);
+        basic.pause(3000)
+        pins.servoWritePin(AnalogPin.P2, 80)
+        basic.pause(3000)
+        pins.analogWritePin(AnalogPin.P2, 0)
+    }
+    basic.pause(5000);
+})
+```
+
+https://youtu.be/7eC_VjH1eP0

docs/projects/plant-watering/make.md

@@ -0,0 +1,24 @@
+# Make
+
+
+## The pump
+
+Follow the instructions on the move to build a mini water-pump using a @boardname@ and a servo.
+
+https://youtu.be/jANCdtkJAKY
+
+
+## The soil moisture sensor
+
+Follow the instructions of the [soil moisture project](/projects/soil-moisture) to build a soil moisture sensor 
+and upload the code to your @boardname@. 
+
+The final wiring should look like this:
+
+![](/static/mb/projects/plant-watering/make.jpg)
+
+### ~button /projects/plant-watering/code
+
+Code
+
+### ~

docs/projects/soil-moisture/code.md

@@ -55,6 +55,8 @@ for dry dirt.
 * insert the nails in the wet dirt, press ``B`` and note the value. You should see a value close to ``1000``
 for dry dirt.
 
+https://youtu.be/S8NppVT_paw
+
 ## Step 3: Don't waste energy!
 
 ![](/static/mb/projects/soil-moisture/nailsp1.jpg)