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Before you can build an awesome robot with your Hummingbird, you need to know how to use all the parts.
This lesson will first show you how to use the Hummingbird outputs, the lights and motors. These components are called outputs because programs in Snap! send commands to them to make something happen. Then you will learn how to use the Hummingbird inputs, the sensors that provide information to the robot about its environment.
The first will show you how to attach components to the Hummingbird board, and the second will show you how to connect the Hummingbird to the computer and how to open Snap! when using the Hummingbird.
This program must remain open the entire time that you are programming in Snap!. It is like a translator between Snap! and your Hummingbird board.
NOTE: On a Mac, the USB cord for the Hummingbird must be plugged in before you open the Birdbrain Robot Server.
To write a program, you will drag blocks from the Blocks area to the Scripts area. In Snap!, programs are also called scripts. You can use Snap! to write scripts that use the Hummingbird or scripts that use cartoon characters called sprites. These lessons will focus on the Hummingbird. To learn more about using sprites to create an animation that runs in the Stage area, please see the Resources section at the end of this lesson.
The Blocks area in Snap! contains 8 different menus - Motion, Looks, Sound, etc. Click on the different menus to get an idea of the blocks that they contain. The Hummingbird blocks that you will use in this lesson are located on the Motion, Looks, Sound, and Sensing menus.
To save a new project in Snap!, click on File and then Export project. Give your project a name and then click OK. Your program will be saved as a .xml file. To open a file, select File and then Import. The video below also describes two other methods of saving.
First, you will learn to use the lights, which are also called LEDs. The Hummingbird kit contains two types of LEDs, single color LEDs and tri-color LEDs. Single color LEDs have two wires, while tri-color LEDs have four wires.
A single color LED can be connected to one of four ports labeled “LEDS” on the Hummingbird board. Since you have four ports, you can connect up to four single color LEDs. The black LED wire should be connected to the ‘-’ terminal, while the colored wire should be connected to the ‘+’ terminal.
The LED blocks for the Hummingbird are located at the very bottom of the Looks menu in Snap!. The Hummingbird LED block is used to control a single color LED. This block requires two numbers. The number on the left is the number of the Hummingbird port to which the LED is attached. This will be a number between 1 and 4. In the picture above, the LED is connected to LED port 1.
The second number in the Hummingbird LED block is the intensity of the LED. This is a number between 0 and 100. 0 means that the LED is off, and 100 means that the LED is at maximum brightness.
This is your first program! Click on this block to run your program. The LED should turn on.
Change the 50 to 0 and click on the block again.
This should make the LED turn off. Change the 0 to 100 and click on the block. This is the maximum brightness of the LED. Try out other numbers between 0 and 100 to explore the different levels of brightness that are possible.
LEDs are quite small, but you can use a styrofoam ball to diffuse the light. This will make the light appear larger.
So far, you have been running your program by clicking on it. You can also use an event to start a program. An event is an action that the computer can recognize. For example, you might press a key on the keyboard. Click on the Control menu.
Notice that the shape of this block shows you that it must be at the top of a script. It can't be connected below another block.
Now you can run your program by pressing the space bar. Try using the space bar to turn on the LED.
A menu will pop up that will allow you to select other keys. Modify your program so that the LED turns on when you press 'o.'
You may have already discovered that you can write multiple scripts in the Scripts area. Add a second script that turns the LED off when you press 'x.'
The wait block can be found on Control menu. This block pauses the program for the number of seconds shown in the block. This number can be a whole number or a decimal number.
You can use the wait block to turn the LED on for a certain period of time. For example, this program will turn the LED on for three seconds and then turn it off.
Connect a second LED to LED port 2. Write a script that turns the first LED on and then waits 2 seconds. Then the script should turn the second LED on for 2 seconds. Then the program should turn both LEDs off. Remember to save your work!
When Snap! reaches a Hummingbird LED block, it sets the LED and moves immediately to the next block. This means that if you do not have a wait block between two commands for the same LED, you may not see the effects of the first block. For example, you may not see the LED turn on when you run the script below. Place a wait block between the Hummingbird LED blocks in order to see the LED turn on and then off.
Write a program that turns two LEDs on at different intensities, waits five seconds, and then turns both LEDs off.
It is good programming practice to always turn off your LEDs at the end of the program. They may go off automatically after a few seconds (particularly on Chromebooks), but this can be unpredictable.
A tri-color LED can be attached to one of the two ports labeled “TRI-COLOR” on the Hummingbird board. The four wires of the tri-color LED are red, green, blue, and black. The black wire should be connected to the ‘-’ terminal. The red wire should be connected to the ‘R’ terminal, the green to the ‘G’ terminal, and the blue to the ‘B’ terminal.
The tri-color LED actually has three tiny lights inside it. One is red, one is green, and one is blue. This is important for programming the tri-color LED. The Hummingbird TRI-LED block is used to control a tri-color LED. This block requires four numbers. The number on the left is the number of the port to which the tri-color LED is attached (1 or 2). The other numbers are labelled R, G, and B. R controls the amount of red light from 0 (none) to 100 (maximum brightness). G and B control the amount of green and blue light, respectively, from 0 to 100. As an example, this block makes a tri-color LED in port 1 turn green.
What do you think this script will do? Make a prediction and then try it out. How do you turn the tri-color LED off?
Write four scripts to turn the tri-color LED four different colors. Each script should use a when key pressed block and a Hummingbird TRI-LED block. For example, the 'a' key might make the LED aqua.
Think about how you might turn an LED on and off repeatedly. One way to do this would be to use a long sequence of commands, but it is much simpler to use the forever block in the Control menu. This block is called a loop. A loop is a programming structure that repeats a portion of a program. Look at the Control menu. Which of the other blocks do you think might be loops?
Other blocks can be placed inside the forever block. The forever block repeats the blocks inside it until you press the stop sign to stop the program. The loop shown blinks the tri-color LED from green to blue. The loop repeats the four blocks inside it over and over. After the second wait block, the program immediately goes back to the first block inside the loop, the block that turns the LED green. What happens if you remove the second wait block?
The repeat block is a loop that repeats the blocks inside it a certain number of times. For example, this program makes the tri-color LED change from green to blue ten times.
After the loop shown above ends, the light just stays blue. If you want to turn the LED off at the end of the script, you need to add a command below the repeat block.
Make a tri-color LED blink on and off in your favorite color at least ten times in five seconds. The tri-color LED should blink evenly - in other words, it should be off for the same amount of time that it is on. Next, add a single color LED. The single color LED should be off when the tri-color is on and on when the tri-color is off.
The Hummingbird kit works with three different kinds of motors: vibration motors, servo motors, and gear motors.
A vibration motor can be attached to one of the two ports labeled “VIBRATION” on the Hummingbird board. It does not matter which wire is attached to ‘+’ and which is attached to ‘-.’
The blocks to control the Hummingbird motors are located at the bottom of the Motion menu. You may need to scroll down to see them. The Hummingbird Vibration block is used to control the vibration motor. This block requires two numbers. The number on the left is the port attached to the vibration motor (1 or 2) and the second number is the speed of vibration from 0 to 100. 0 means no vibration, and 100 means maximum vibration.
As an example, this script turns the vibration motor on for five seconds and then turns it off.
Write a program that turns both a vibration motor and a single color LED on for four seconds and then off for four seconds. Then place these commands within a loop to repeat them five times.
Small, very light items such as googly eyes can be attached to a vibration motor so that they move when the motor vibrates.
A servo motor is a motor that moves to a particular angle. The Hummingbird servo motor can rotate to any angle from 0° to 180°.
Important Note: When using the servo motor, you must also use the AC power adapter (or a battery pack). Otherwise, the Hummingbird board will not have enough power to run the motor.
The servo motor has a small plug. This plug should be connected to one of the four sets of pins in the "SERVOS" section of the Hummingbird board. Each set of three pins is one servo port. The black wire should be connected to the ‘-’ pin, the red wire to the ‘+,’ and the yellow wire to the ‘S.’
This will help you to see the movement of the servo motor more easily. If you don't want to use hot glue, you can tape a feather to the plastic circle.
The Hummingbird Servo block is used to move the servo motor. It requires two numbers. The number on the left is the port attached to the servo (1-4) and the second number is the angle (0° to 180°). The command below should move a servo motor attached to port 1 to 0°.
If you write a script with more than one angle, make sure to put a wait block between the Hummingbird Servo blocks. If you omit the wait block from the script below, the servo will not have time to move to 90° before the command to move to 30°.
This script is supposed to move the servo motor repeatedly to two different angles, but there is a problem. Try out this script, and figure out how to correct it.
Write a script that repeatedly moves the servo to five different angles. Make the tri-color LED a different color at each angle.
Before you start building with a servo, always set it to 90°. This will make sure that the servo can move both left and right once it is attached to your robot.
The gear motor can be attached to either of the ports labeled “MOTORS” on the Hummingbird board. It does not matter which wire is attached to ‘+’ and which is attached to ‘-.’ When using the gear motor, you must also use the AC power adapter (or a battery pack).
Important Note: Do not cut the zip ties off your motors. Without the zip tie, the wires may break off the motor.
The Hummingbird Motor block is used to control the gear motor. This block requires two numbers. The number on the left is the port attached to the motor. The number on the right is labeled “speed.” This number can be any whole number from -100 to 100. As an example, this script turns the motor on for two seconds and then off.
Use a small screwdriver to attach a wheel to the motor so that you can see it move more easily (or just place the wheel on the motor without using a screw). Try several speeds between 0 and 100. Describe how the speed affects the motor. Try several negative speeds. What does it mean for the speed to be negative?
Important Note: You may notice that your motor rotates clockwise for positive numbers, while your neighbor's rotates counterclockwise for the same number. This just means that you and your neighbor chose '+' and '-' differently when you connected your motors. Either way is fine!
Write a program that rotates the motor first in one direction, then in the other. Next, use a loop to repeat these actions.
The Say This block can be used to make the computer say words or phrases; you can find it on the Sound menu. You can place words in this block, and the computer will say them over its speakers.
When it runs the Say This block, the computer starts to say the words and then moves on immediately to the next block. This means that in this script, the tri-color LED will turn on as soon as the computer starts talking.
Write a program that uses two Say This blocks. What block do you need to place between your Say This blocks?
Are you ready to use all the Hummingbird outputs? Write a program that includes the following:
The Hummingbird LEDs and motors are output devices. Scripts in Snap! send commands to these devices to make something happen. The Hummingbird sensors, on the other hand, are input devices. They send information to the Snap! program. The Snap! program can use this information to make a decision or control a light or a motor.
All of the sensors are attached to the Hummingbird in the same way. A sensor can be attached to any one of the four ports labeled “SENSORS.” Each sensor has a red wire, a black wire, and a yellow wire. The red wire should be connected to ‘+,’ the black to ‘-,’ and the yellow to ‘S.’
The distance sensor measures the distance to the closest object. Attach a distance sensor to the Hummingbird. Drag the HB Distance CM block into the Scripts area away from the other blocks. Make sure that the port number is set to the port attached to the distance sensor. Click on this block to see the current value of the sensor. Then hold something in front of the sensor and click the block again. Is the value of the distance sensor different?
The distance sensor measures the distance to an object in centimeters. The value of the distance sensor is between about 8 cm and 100 cm. The sensor cannot detect objects very close to the sensor or very far from it. It works best in the range of 20 cm to 60 cm.
To see the value of the distance sensor change, it is helpful to create a variable. A variable is just a name that represents a value. You will now create a variable named “distance” that will hold the value of the distance sensor and display that value on the screen.
You will notice that the Variables menu looks different now. It contains some blocks that you can use to change the value of your variable. Also, the value of the variable is shown in the top-left corner of the stage.
We want to set the value of our variable equal to the value of the distance sensor. To do this, we can use the set to block. We will place this block inside a forever loop to continually set the variable to the value of the sensor. Use the drop-down menu in the set to block to select the name of the variable.
Run the script above and watch the value of the distance variable change as you move an object back and forth in front of the sensor.
You can use the distance sensor to enable a robot to make a decision. The if else block in Snap! is a decision block. This block is found on the Control menu. What do you notice about it?
The if else block has spaces in the middle that can hold other Snap! blocks. In addition, the if else block contains a hexagonal space. This space requires a Boolean block. A Boolean block is a block that can be either true or false.
You can use the distance sensor to create a Boolean block using these two blocks, which are found on the Operators menu. Notice that these blocks match the shape of the space in the if else block.
This block is true if the value of the distance sensor is greater than 30 cm, and false otherwise. The value that the Boolean block uses to make a decision is called the threshold. In this case, the threshold is 30 cm. Click on the green part of the block with an object in front of the sensor. Is the block false?
It checks the value of the Boolean block inside it. If the value is true, then the script runs the blocks inside the top part of the if else block. If the value of the Boolean block is false, then the script runs the blocks in the bottom part of the if else.
As an example, consider this script. When you press the space bar, it will check the distance sensor. If the distance to an object is greater than 30 cm, the tri-color LED will turn green. Otherwise, it will turn red. Try it out!
The script above makes a decision each time you press the space bar. You may also want to repeat this decision over and over. Then the light will turn red whenever something gets close to the sensor. To do this, place the if else block inside a forever loop.
Write a program that blinks a red light and moves a servo motor when an object is close to the distance sensor. When nothing is near the distance sensor, the light should be off and the servo should not move.
The Boolean block for the if else is checked each time the program repeats the decision. However, the Boolean block is not checked during the statements inside the top or the bottom of the if else block. Try out the script below. In this script, the motor should be on when something is close to the distance sensor. When you run this program, you will notice that the program does not respond quickly when you move an object toward or away from the distance sensor. How can you modify this program to make it respond more quickly to a change in the value of the distance sensor?
The rotary knob is another sensor; this sensor measures how much you have turned the knob. You can use the Hummingbird Knob block to find the value of this sensor. This value will be between 0 and 100. Always remember to make sure that the Hummingbird Knob block is set to the port attached to the rotary knob.
Attach the knob to the Hummingbird board. Declare a variable named "knob" and write a script that uses the set to block to continually set this variable to the value of the Hummingbird Knobblock. Then turn the knob all the way to the left. What is the value of the Hummingbird Knob block? What is the value of the Hummingbird Knob block when the knob is turned all the way to the right?
Write a program that turns on a single color LED when the knob is turned far enough to the left. When the knob is turned far enough to the right, the LED should be off. What will your threshold be for this program? Remember, the threshold is the value that the Boolean block uses to make a decision.
In the previous exercise, you used the rotary knob to decide whether the LED should be on or off. Instead, you could use the knob to determine the brightness of the LED. Because the Hummingbird Knobblock is a number between 0 and 100, you can place it inside the Hummingbird Knobblock to set the intensity of the light. Try out the script below. The foreverloop repeatedly changes the brightness of the LED to match the value of the knob.
Use the knob to control a gear motor and the amount of red in a tri-color LED (the amount of green and blue can be whatever you want). These components should change at the same time.
The rotary knob is useful for controlling the LEDs because its range (0-100) is the same as the input range for these components. If you place the knob block inside the Hummingbird Servo block as shown, the servo will only move from 0° to 100°.
You can make the servo move from 0° to 180° using an arithmetic block from the Operators menu. These blocks enable you to add, subtract, multiply, and divide numbers.
Place the Hummingbird Knob block inside a multiplication block as shown. What number should you put in the blank so that the knob moves the servo from 0° to 180°? When the value of the knob is 0, the servo should be at 0°. When the value of the knob is 100, the servo should be at 180°.
What do you think the script shown will do? Make a prediction before you try it out.
Don't forget to set the port in the sensor block to the port on the Hummingbird board that you are actually using! If the value of the sensor is not changing as expected, be sure to check that the sensor block is reading the correct port.
The light sensor measures the amount of light around it. This sensor is very similar to the other sensors that you have learned about. You can use the Hummingbird Light block to find the value of this sensor. This value will be between 0 and 100. Always remember to make sure that the Hummingbird Light block is set to the appropriate port.
Attach the light sensor to the Hummingbird board. Use the Hummingbird Light block to measure the amount of light in your room. Then measure the value of the light sensor when you cover it with your hand. The average of these two values is a good threshold for the light sensor.
Write a script that turns on a vibration motor when the light sensor detects that it is dark. Otherwise, the vibration motor should be off.
You have now practiced using all the Hummingbird motors and lights, as well as three of the sensors. There are other sensors, including a temperature sensor and a sound sensor. These work very similarly to the sensors you have already used. The HB Temperature C block tells you the temperature in Celsius, and the Hummingbird Sound block tells you the amount of noise around the Hummingbird on a scale of 0-100.
The last two exercises below will give you some practice using multiple sensors. After you have completed these, you will be ready to create many exciting, unique Hummingbird robots!
Write a program that uses the knob sensor to control the color of a tri-color LED. However, the LED should only be on when an object is less than 30 cm from the distance sensor. Otherwise, the LED should be off.
Write a program that sends the servo to four different angles based on the values of the distance and light sensors. All of the values are shown in the table below.
|Greater than 20 cm||Above the threshold||0°|
|Greater than 20 cm||Below the threshold||60°|
|Less than 20 cm||Above the threshold||120°|
|Less than 20 cm||Below the threshold||180°|