Write Code: Move the Servo

1. Type: “myservo.write(180);” after “delay(2000);”

STEM Connections

Remember, the write function determines the angle to which a standard Servo moves. So, the line of code “myservo.write(180);” tells the standard Servo to move to 180°.

Before the Arduino board runs this line of code, the Servo was at angle 0°. When the Arduino board runs this line of code, it will cause the standard Servo to rotate to the right from 0° to 180°.

In the previous two steps, you told the Servo to move to 0°, then pause at that angle for 2000 milliseconds (or 2 seconds). After adding this line, the Servo will move to 180°.

Again, the write function will have a different effect on the continuous Servo, but we will explore that more in later steps.

At the Thinkabit Lab, we provide an in-depth explanation of what it means to add the line of code, “myservo.write(180);” after “delay(2000);” as follows:

• Explain that without adding this line of code with a different command, the standard Servo would remain at 0° indefinitely. A different command is needed for the Servo to move. Like the LED Blink code, where there were 2 states: State 1: LED on and State 2: LED off. Likewise, we also need (at least) 2 states for the standard Servo to see a back and forth motion. Without giving a new command to the Servo, the previous line of ‘delay’ would be unnecessary because there wouldn’t be another action to switch to.

• Explain that the Arduino board reads through the code quickly, without the next delay, it will look like the Servo remains at 0° because the Servo needs time to move to the desired position.

If you are using the Thinkabit Lab Notebook:
 

Have students fill in the next blank on page 15:
myservo.write(180);               Servo action '180'      

Explain to students that this action varies depending on which Servo we are using.  Alternatively, you could write "small Servo to 180°, big Servo spin fast right"

Alternatively, you can write the entire code on the computer and fill in the notebook at the end.

‘write’ didn’t turn orange

1. Check the spelling of the word “write” and make sure that no letters are capitalized.

2. Check to make sure that there is a period between “myservo” and “write”.

3. Check to make sure that there is a semicolon after “myservo.write(0);”

4. If it changed colors to a different color, the Arduino software may have been updated.  As long as it is colored, the code should still work properly.