You can build your own model garage with a functioning automatic garage door powered by a Circuit Playground Express, servo motor, and pushrod mechanism created with a paperclip, cardboard, a dowel, and a straw!

You'll code the Circuit Playground Express using MakeCode so that it can open or close your garage door at the press of a button, and even build a light activation mode that will automatically open the door for you!

Parts & Materials

For materials, you'll need:

• small, corrugated cardboard box
• drinking straw
• wooden dowel or bamboo skewer
• paper clip.

The electronics you'll need are listed below.

Tools

Here are the tools you'll use to build the project:

• Hobby knife
• Metal ruler
• Hot melt glue gun and hot melt glue -- either low or high temperature is fine
• Pencil
• Small pair of pliers for paper clip bending (optional, you can do it with your fingers too!)

To open the garage door we'll make a mechanism that transfers the rotation of our servo to the rotation of the door.

We could try to mount the door directly to the servo's shaft, but this would be a bit tricky, and pretty bulky looking.

Instead, we'll transfer the rotation of the servo over a short distance using a pushrod made from a paperclip.

Take a look at the diagrams below -- there are a few key things to note:

• The servo shaft rotates clockwise, and the servo arm rotates along with it
• The pushrod translates (moves) to the right and slightly down as it is pushed by the servo arm
• The pushrod pushes the door's control horn to the right
• The door is on a hinge (made from a drinking straw) which rotates counterclockwise around the door pivot dowel

Later in the guide, we'll build a similar mechanism for our garage.

You can code your Circuit Playground Express using MakeCode to open and close with buttons presses and also using the light sensor! If you aren't already familiar with MakeCode, check out this guide to get started, then return here when you're ready.

Functions

Here's what we will set up the Circuit Playground Express to do:

• Open the garage door by turning the servo when the A button is pressed
• Close the garage when the B button is pressed
• Watch for a bright light on the light sensor
  • When a bright light is detected, open the door, wait five seconds, and then close the door

Those are the basics, but we'll also get fancy and set up some lights and sounds to accompany these functions.

On Start

First, we'll set up some things that happen as soon as the program starts. Begin by dragging an on start block from the LOOPS category into your program canvas area.

Place a set all pixels to block into the on start block, and change the color to orange. This will be the color of the NeoPixel ring on the Circuit Playground Express when the program starts.

It's also nice to have a startup sound. Pull in a play tone at block. Change the note to High A and the duration to 1/2 beat.

Variables

Since we'll be setting open and closed values for the servo angles multiple times in the program, it's helpful to set up a couple of variables with these numbers which we can then use over and over again.

From the variables category click Make a Variable... and then create one and name it 'closed'. Repeat this a second time for one called 'open'.

Drag in a block called set closed to into the on start loop. Then duplicate this block and change the drop down menu to the open variable.

You may need to adjust these values later but for now use 170 and 70 as shown here.

Servo Write

We'll have the servo automatically go to the closed position when the program starts.

From the pins category, drag in a servo right block. Change the pin from the default A1 to A2. (You can use either of these two pads on the Circuit Playground Express to control a servo.)

Then from the variables category drag in closed variable into the servo right pin block.

Light it Up

From the input category drag in the light threshold block. Change the first drop-down item from dark to bright. Then set the value to something pretty high such as 240. This will vary depending on how bright the light source is that you want to use to open the garage door.

Lights Out

Finally we will turn off all of the NeoPixel LEDs by dragging in a set all pixels block from light category, and then changing the color value to black.

Buttons

Next we will set up the Circuit Playground Express so that pressing the A button will sound a tone and open the garage. We will set up to the B button to close the garage.

Create a set of blocks just like the ones shown in the image below.

Light Sensor

Finally, we will set up a light sensor block so that when a bright light is detected the following actions occur:

• The LEDs will turn blue
• A melody will play
• The servo will open the door.
• Then an animation will play for five seconds, giving a toy car time to pull into the garage
• The lights will change to red
• A different melody will play
• The door will close
• The LEDs will turn off

Add the blocks needed to do these actions, as shown in the block set below.

Your program is complete! There's an interactive embedded version of it below. You can now download your program from your MakeCode session, press the reset button on your Circuit Playground Express, and drag the program onto it.

You're ready to test it out!

A small cardboard box will make for the perfect garage for your die cast cars or small robots. We'll make the garage and add the door mechanism next.

Turn the servo to the clockwise position and make sure the door swings open. If it doesn't, or has difficulty, you can adjust the position of the pushrod in the control horn by poking additional holes as "lower" or "higher" positions until it works smoothly.

Circuit Playground Express Controll

Now, connect the Circuit Playground Express to the servo with this wiring:

• CPX VOUT to servo orange power
  
• CPX GND to servo brown ground
  
• CPX A2 to servo yellow signal
  

Plug in the USB cable to power the Circuit Playground Express and test it out -- push the A button and it opens! B and it closes!

You can use some masking tape or double stick foam tape to mount your Circuit Playground Express on the garage wall next to the door.

Grab a flashlight and shine it at the light sensor. I opens automatically!!

Have fun with your brand new garage. You can now cut out some additional windows, decorate it, and maybe think about additional automation and lighting you can build for it. A "neon" sign would look rad.