Testing the buttons

worksheet.md

@@ -2,4 +2,10 @@
 
 In this resource you will make a tweeting touch screen photo booth using a Raspberry Pi.
 
-## The First Step
+## Making the photo booth
+
+Carrie Anne / James to write up how they set up the touch screen, camera and button hardware
+
+Buttons wired to pins 23 and 25 please
+
+Then a [link to worksheet 2](worksheet2.md)

worksheet2.md

@@ -0,0 +1,66 @@
+# The All Seeing Pi (Part 2 - Software)
+
+In this resource you will make a tweeting touch screen photo booth using a Raspberry Pi.
+
+## Test the buttons
+
+1. With the hardware set up, we can begin to program the software that will make everything work. To begin, open the file explorer, then right click on a blank space inside the file explorer window.
+
+  ![File Explorer](images/file-explorer.png)
+
+1. Select `Create new` and then click `Folder`
+
+  ![Create folder menu](images/create-folder.png)
+
+1. Type in the name of the folder where you will store the code and the photographs. We chose to call ours `allseeingpi`. Make a note of the path to this folder which is displayed in the bar at the top, which should be `/home/pi/allseeingpi`
+
+1. From the "Programming" menu, open up "Python 3"
+
+  ![Open Python 3](images/python3-app-menu.png)
+
+1. Create a new Python file by clicking on `File` > `New File`.
+
+1. Click on `File` > `Save` and save your file into the `allseeingpi` folder you just created, with the filename `allseeingpi.py`.
+
+1. We will need the `picamera` and the `gpiozero` libraries. At the start of your Python file add two import statements:
+
+```python
+from picamera import PiCamera
+from gpiozero import Button
+```
+
+1. Next we will set up the buttons. On the [previous worksheet](worksheet.md) we wired our buttons to pins 23 and 25. Let's go ahead and set both buttons up, even though we will not use the `next_overlay_btn` until later on.
+
+  ```python
+  next_overlay_btn = Button(23)
+  take_pic_btn = Button(25)
+  ```
+
+1. Now we will use gpiozero to tell the buttons what to do when pressed. In the code below, `next_overlay` and `take_picture` are functions which will be called when the corresponding button is pressed:
+
+  ```python
+    next_overlay_btn.when_pressed = next_overlay
+    take_pic_btn.when_pressed = take_picture
+  ```
+
+1. We need to write these two functions so that the buttons have something to do when they are pressed. Functions are usually written at the start of a program immediately after the `import` statements. Add the functions, but with some placeholder code to just print a message when they are pressed, so we can test them.
+
+  ```python
+  def next_overlay():
+    print("Next overlay")
+
+  def take_picture():
+    print("Take a picture")
+  ```
+
+1. Press `F5`, save and run your program. Try pressing each button and check that a different message pops up for each in the Python shell.
+
+    ![Test the buttons](images/test-buttons.png)
+
+## Add an overlay
+
+## Change overlays with a button
+
+## Tweet picture
+
+## Create a GUI