Funduino Street

Assembling Calle is quite easy: you only need to install the two drive wheels and the front caster. First, break off the side edges of the circuit board by hand - they are only needed for stability during manufacturing.

Attach the motors to the underside using the white brackets. Make sure the protruding part of the bracket and the motor shaft point outward.

Feed the cables from both motors through the opening in the circuit board to the top, then plug the JST connectors into the designated sockets. It does not matter which way the black and red wires are oriented, since the connectors only fit one way.

The front caster acts like a support wheel and follows all the movements caused by the two drive motors.

Attach two hexagonal spacers between the caster and the circuit board using two short nylon screws. These raise the caster to a height that matches the drive wheels. Then attach the caster underneath the circuit board by inserting two more screws through the designated holes from the top and fastening them into the spacers.

Finally, plug the remaining components—the line-tracking sensors and the ultrasonic sensor—into the top of the circuit board.

Calle is programmed using the MakeCode IDE. If you’ve never worked with a Calliope before, you should familiarize yourself with it first.

In MakeCode, a new program is called a “project.” Click “New Project,” give it a name - in this example, “Calle” - and click “Create.” Since Calle is designed for the Calliope mini V3, select this microcontroller.

On the left, you’ll see the selected controller, with the programming blocks next to it. The large area in the middle already contains the “on start” and “forever” blocks - these are there by default.

Task: Calle's two headlights should be switched on and off using buttons A and B. They are two LEDs, both connected to pin C12 on the Calliope.

Without programming, contact C12 has a status of “0” – no voltage is applied, and the LEDs do not light up. With the “write digital value of pin C12 to 1” block, you change the status to “1,” and the Calliope outputs 3.3 V at this contact.

Go to Advanced → Pins, select “write digital value of pin P0 to 0” in the Digital section, and set the pin to C12. Duplicate this block: set it to 1 for button A and to 0 for button B.

Then click “Download,” connect the cable to the Calliope and computer, click “Next,” and then “Pair.” Select the Calliope in the pop-up – you’re now connected.

The line sensors output a voltage—or not—depending on whether they detect a light surface or a dark line.

To use the reading later, you need a place to store it: a variable. Go to Variables → Create a variable and create one named “LinienVerfolgerLinks”. Drag the “set LinienVerfolgerLinks to 0” block into the “forever” block.

Then click Advanced → Digital, drag “digital values from pin P0” into the “0” slot, and change the pin to C15.

To see what the sensor reports, add the “show text” block from Basics and replace the default text with the variable. After uploading, a “0” or “1” appears on the LED matrix.

The principle of line following is simple: If Calle veers to the left of the line, the left motor should turn faster, making the robot turn right. If it veers to the right, the right motor turns faster.

With two sensors, there are four cases: both light, both dark, left dark and right light, left light and right dark. When both sensors detect “dark,” the robot is centered on the line and can go full speed.

To program it, create two variables, “LineFollowerLeft” and “LineFollowerRight,” and assign them the digital values from contacts C14 and C15. From the Logic category, select “if true then otherwise” and expand the block twice using the plus symbol. Check the four cases using two comparisons each, joined with “and.”

Motor control is already built into MakeCode: The right motor is M0, and the left is M1.

There is a module with two cylinders on the front of the Calliope that looks like two eyes. It is an ultrasonic sensor.

It works like a bat: It emits ultrasonic waves that are reflected by objects and return like an echo. The Calliope calculates the distance based on how long the wave takes to travel.

External modules aren’t included in MakeCode by default. Click “Extensions” and enter the direct link to the library in the search bar: github.com/Funduino-GmbH/RCW0001

After clicking the “RCW-0001” card, a new category appears with a single block: “Ultrasonic sensor (in cm) trigger on C8 and echo on C9”.

To display the distance, drag “show number 0” from the Basics category into the “forever” block and replace the “0” with the ultrasonic block.

The LED matrix display has one drawback: It takes quite a while for the number to scroll across, and the program only continues once it’s finished. If data needs to be processed quickly, “show number” and “show text” aren’t suitable.

Instead, use serial communication. Under Advanced → Serial, place the “redirect serial to USB” block inside “on start” and “serial write line” inside “forever”. After downloading, a new option appears on the left side of the webpage, where you can view the measured values.

To reuse the values, create a variable called “Distance”, put the ultrasonic block in “set Distance to 0”, and add the variable to the serial output. This lets you read the data while other program blocks run in parallel.

Now you play a tone depending on the measured distance. In computer science, this kind of dependency is called an “if statement” or an “if-then function.”

From the Logic category, take “if true then,” from the Sound category, the “play note … for …” block, and also the “Greater than” comparison from Logic. Put these blocks together.

To expand it, click the plus sign in the dark green block: Calle should drive forward when the distance is greater than 30 and stop when it is less. From the Motors category, take the “Motor” block and change it from M0 to M0 & M1. Below 30, set the value to 0; otherwise, set it to 50 percent so Calle doesn’t drive too fast.

Calle has six special light sources: intelligent WS2812 LEDs, often called NeoPixels. They can shine in thousands of colors, and several hundred of them share a single data line.

Calle uses two pins: P2 controls the three LEDs on the right side, and P3 controls the three on the left.

Under “Extensions,” search for “NeoPixel” and install the library. Then, in the new category, click “Set strip to NeoPixels on pin P0 …” and set the pin to P2. For the left side, create a second variable - we’ll call it “strip2” - and set it to P3.

Use the “show color” block to set the color. To stop the colors from changing too quickly, add “pause (ms) 1000” from the Basics category.

You can control the LEDs individually using NeoPixel → more with the “strip set color of NeoPixel 0 to red” block. On both sides, the numbering runs from 0 at the very front to 2 at the very back.