7. case 04 trimpot#

7.1. Introduction#

The trimpot is a common pressure regulation component. In this case, we are going to read output voltage of the trimpot and show the voltage with a bar graph in 5*5 LED allay of micro:bit.

7.3. Hardware Connect#

../../_images/LMsve7H.png Connect circuit as above picture and put 2 AAA batteries to the batteries pack.

7.4. Principles of Circuits#

../../_images/VFmWZkG.png

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

7.5. Introduction of Components#

Trimpot#

The trimpot is a pressure regulation component which included a resistance and a slide system. The resistance measured varies based on the movement of a knob or slider between the middle terminal and outer terminals. There is a 10KΩ trimpot on the experiment box. When it turns left, it will be 0Ω; when it turns right, it will be 10KΩ.

../../_images/jHZQhOu.png

7.6. Software#

Step 1#

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

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

../../_images/t34k5Zb.png

Step 2#

../../_images/3Ekc31T.png

Snap plot bar graph into the forever to show a bar graph.（A bar graph is a kind of table which can show number by diffrent lengths.）

“analog read pin” is to read a signal of a pin.（0~1023）

Program#

Program link：https://makecode.microbit.org/_VewWgwe8HVT1

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

7.7. Result#

Rotate the trimpot, the height of the bar graph will change.

../../_images/WDagGas.gif

7.8. think#

Is the trimpot could be a fixed resistance？

7.9. Questions#

7.10. More Information#