Vroom, vroom... Piperbot is making his daring escape as the Cheeseteroid hurtles toward Earth!

Let’s start by gathering our supplies. For this project, you’ll need your Pico and breadboard, 6 jumper wires, 3 LEDs, 3 resistors, and both pairs of Beam Break Sensors.

The jumper wires don't have to be the same color as the ones in the diagram - you can use any color wires that you have.

You'll also need the parts that came with the Beam Break Sensors. 4 small wood pieces, 2 larger wood pieces, two black, C-shaped plastic pieces, and 1 Hot Wheels™ track, as shown.

Your Beam Break Sensors have two parts - an emitter and a receiver. The emitter sends out a beam of infrared light and the receiver senses whether that beam is broken. So let's set up your Beam Break gates

To start, line up the Beam Break Sensor that has 3 wires (the receiver) with the hole on one of the smaller wood pieces.

Grab the C-shaped plastic piece, and hold the Beam Break receiver in the black plastic piece like the picture below. Then, hook the small wood piece in at the top and push in the bottom until the small wood piece is vertical.

Next, feed the wires through the hole on the bottom of the black plastic piece.

Now, grab one of the Beam Break Sensors with 2 wires. This is the emitter side of the Beam Break Sensor.

Install it and the small wood piece just like you did on the other side - use the picture below as a guide.

Then, feed the 2 wires through both holes of the black plastic piece.

Do this again for the other pair of Beam Break Sensors. When both sets are ready, click NEXT.

Awesome, now we've got to make space for the track in between the emitter and the receiver!

Take the larger wood piece and push it straight down over the center of the black plastic piece.

The black plastic piece should stick through the cutout in the wood piece. Do this for both sets of Sensors.

Now that both Sensors are attached to the plastic and wood pieces, we will call the finished part a "Beam Break Module". When you finish building both Beam Break Modules, click NEXT.

Look carefully at the image below. The orange Hot Wheels™ track will hook onto the Beam Break Module like this.

Attach both of the Beam Break Modules to the track, as shown below, and slide them down the track a little.

Look for the small card that came with your Beam Break kit. The card has a ruler printed on one side. Slide the Beam Break Modules apart on the track and use the ruler to make sure the Beam Break Modules are 8 centimeters apart.

When both Sensors are attached to the track, click NEXT.

Awesome! Now that the track is ready, let's build the Beam Break circuits! Let's start by building the 3-LED circuit we built back in Traffic Light.
First, create a GROUND rail by connecting a GROUND pin to the (-) blue column on the edge of the breadboard, as shown at the top of the picture below.

Insert a Red LED into the breadboard across the center gap. Make sure the shorter leg of the LED is on the same side as the GROUND wire you just connected.

Connect a resistor between the short leg of the LED and the (-) blue column on the edge of the breadboard.

Then, connect a jumper wire from GP15 on the Pico to the long leg of the Red LED.

Repeat the steps above to add a Yellow LED connected to GP14 and a Green LED connected to GP13.

Click NEXT when you are finished building the LED part of the circuit.

The Beam Break Modules have a lot of wires! Don't worry, they are actually easy to connect! We'll do it one step at a time, using the image below as a guide.

Start by connecting the (+) red column on the bottom of the breadboard to the 5V pin of the Pico using a jumper wire.

Next, connect the (-) blue column on the bottom of the breadboard to one of the GROUND pins on the Pico.

Connect all four of the black wires from the Beam Break Modules to the (-) blue column at the bottom of the breadboard. Then, connect all of the red wires from the Beam Break Modules to the (+) red column at the bottom of the breadboard.

Finally, connect the first Beam Break Module's white wire to GP6 on the Pico. Connect the second Beam Break Module's white wire to GP11 on the Pico.

Note that the first Beam Break Module is connected to GP6, and the second Beam Break Module is connected to GP11. When you send the car racing down the track, it needs to break the first beam, and then the second one. If you send it through backwards, the program we build won't work!

When your Beam Break Modules are connected, click NEXT.

But wait, now that we have our Beam Break Modules all wired up, how come we can't see the light emitted by the emitter?


The emitter (the Sensor with two wires) is an infrared LED. Infrared light is special because we can't see it with our eyes.

If you have a cell phone or digital camera, the camera's Sensor can probably see it though! Here's a video clip from a cell phone showing the infrared glow from the emitter when it is connected.

The receiver, the other half of the Beam Break Module, uses a device called a phototransistor.

If we break down the word, "photo" means light (think photosynthesis), and "transistors" are digital switches. So a phototransistor is a light-sensitive digital switch!
Shining infrared light on the phototransistor turns it on, and when the car blocks the infrared light, the phototransistor turns off.

All we have to do to get the speed of the car is measure the time between when the first Beam Break Module turns off and when the second one turns off.

We can use that time difference and the distance between the two Beam Break Modules to calculate the speed of the car.

Click NEXT to start building the code to measure the speed of the car.

We want to do a bunch of things here— measure the time of each beam break, calculate the speed, display it, etc.

Instead of writing giant blocks of code, we can break these distinct tasks up into Functions, which are pieces of code that our program can call whenever we want to do a certain task.

Our first task is to measure the time the first beam breaks. How can we define a Function to do this?

Start by dragging out a to do something→return __ block from the Functions menu. Be careful, there are two block in the Functions menu that look similar. Make sure you have the one with the return at the end.

Then, change the name of the to do something block to "beam break time"

We want to wait until the the circuit switches off, right? So let's grab a wait until block from the Chip menu and place it in the to beam break time block. Then, grab an is pin block from the Chip menu and place it inside of the wait until block. Set the is pin block to pin 6.

Now that we're detecting when the beam breaks, we want to save the time when that happens to a variable. How can we do that?

Click the Variables menu and then click the Create variable... button. Name the new variable "first beam time".

Open the Variable menu again and drag out a set first beam time block. Connect it below the wait until block. Next, grab a chip clock block from the Chip menu and place it inside of the set first beam time block.

Our function will now capture the time when the car breaks the first beam.

We need to create another variable to store the time when the second beam is broken. click the Variables menu and then click the Create variable... button. Name the new variable "second beam time"

Right-click the wait until block and select Duplicate. Connect it below the set first beam time block. Change the pin variable on the wait until block to pin 11. Next, right-click the set first beam time and select Duplicate. Connect the new block below the last wait until block. Change the variable on the set block to second beam time.

Click NEXT.

How long did it take for the car to go from breaking the first beam to breaking the second? To figure this out, we need to subtract the first beam break time from the second beam break time.

Grab a __ + __ block from the Logic menu and place it inside the to beam break time block's return value. Then, change the + (plus) to a - (minus).

Grab a second beam time block from the Variables menu and place it in the left side of the __ - __ block. Then, grab a first beam time block from the Variables menu and place it in the right side of the __ - __ block.

Woot! We've done all the work, now how can we see the results? Since you defined a function which returns the time difference, all we have to do is print that result!

Grab a start block from the Chip menu and drag it onto the workspace. Then, grab a repeat forever block from the Loops menu and connect it to the start block. Next, grab a print block from the Chip menu and place it inside of the repeat forever block.

Change the wait time on the repeat forever block to 0.1 seconds, and delete the "_" block inside of the print block by dragging it to the trash can.

Finally, grab the beam break time block from the Functions menu and place it inside of the print block like this.

Now, you're ready to test it out! Click NEXT.

Oh no! As Piperbot speeds away from the incoming Cheesteroid he runs into a pesky traffic light! Can you code up the traffic light to speed up his escape?

Let's build some code that will light up the LEDs in order to make a "Ready, Set, Go" indicator so we know when to push our Hot Wheels™ car down the track.
To make a traffic light, the red LED needs to light up first for 2 seconds. Then, the red LED will turn off and the yellow LED will turn on for 2 seconds. And finally, the green LED will turn on, indicating "Go Go Go"!

Click NEXT to learn how to build the code for the Ready, Set, Go! lights.

Let's build another Function to control the LEDs. Drag out a to do something block from the Functions menu. Then, change the name of the blocks to "ready set go lights".

Drag a turn pin block from the Chip menu and place it inside of the to ready set go lights block. Drag a wait block from the Chip menu and connect it below the turn pin block. Set the variables of the turn pin block to pin 15 and ON, and set the wait time on the wait block to 2 seconds.

Next, right click the turn pin block and select Duplicate. Connect the new block below the wait block. Change it from ON to OFF.

This will turn the red LED on, wait for two seconds, and then turn it off. We need the same code again, but using pin 14 to turn on the yellow LED for 2 seconds.

Use the right click button to duplicate your blocks and set them to pin 14.

Your code will now turn on the red light for 2 seconds, and then turn on the yellow light for 2 seconds.

All the function needs to do now is turn on the green light. Right click one of the turn pin blocks and duplicate it. Set the variables to pin 13 and ON, and connect it below the last block inside of the function.

Click NEXT.

Now that we have our functions, let's put it all together.

We want the Ready, Set, Go! lights to start first, so grab a ready set go lights block from the Functions menu and place it right above the print block inside of the repeat forever block.

Next, our program needs to turn the green LED off when the car goes through the Sensors. Grab a turn pin block from the Chip menu and place it in the repeat forever block after the print block. Set the block's variables to 13 and OFF.

Let's clean up the workspace a bit. Right-click the to beam break time block and select Collapse. Do the same thing to the to ready set go lights block. Collapsing a group of blocks lets them keep working, but shrinks them so they take up less space.

All that's left is to print the speed!

Grab a create text with block from the Values menu and place it into the print block. Then, grab a car speed block from the Variables menu and place it into the top input in the create text with block.

Next, grab a "_" block from the Values menu and place it into the bottom input in the create text with block. Based on your unit conversion, type in either "miles per hour" or "kilometers per hour".

Now that your program is ready, click NEXT to try it out!