10. case 08 servo#

10.1. Introduction#

The servo is a kind of angle servo driver. It is adapted to varying control system. In this case, we are going to use the micro:bit to control rotating of the servo.

10.3. Hardware Connect#

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Connect circuit as above picture and put 2 AAA batteries into batteries pack.

10.4. Principles of Circuits#

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The GND of slot on micro:bit is into innards of batteries’ GND to generate the current loop.

10.5. Introduction of Components#

Servo#

A servo is an automatic control system that consists of a DC motor, a reduction gear unit, a potentiometer and a control circuit. Generally, the servo has its the largest rotation angle (For example:180 deg). Our reference point at a 90deg middle position is defined by a signal frequency of 20ms and a pulse width of 1.5ms. The experiment box included a 180° servo. ../../_images/uqmkhZ6.png

Note: You don’t need to think out some complex questions like pulse width because micro:bit Foundation has converted the servo code to block.

Note: Please note the positive and the negative when you are connecting.

10.6. Software#

Step 1#

Click makecode https://makecode.microbit.org/#

Click on “New Project” and set a new Project.

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Step 2#

Snap the servo write pin and pause block into the forever and set P1 to 0. Pause 2000ms.

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Snap the servo write pin again after the first pause block and set P1 to 180. Pause 2000ms.

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Program#

Program link:https://makecode.microbit.org/_fudJaMCRhE1r

You also could directly download program by visiting website as below:

10.7. Result#

The servo will rotate between 0 deg to 180 deg.

10.8. Think#

If we want to make a thermometer dial by using the NTC and the servo, how do we design the circuit and the programming?

10.9. Questions#

10.10. More Information#