Difference: LEDsAndNopNeoPixel (3 vs. 4)

Revision 42020-05-21 - UliRaich

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META TOPICPARENT	name="Exercises"

LEDs and NeoPixel

Introduction

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Exercise 4: Change the LED light intensity

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The light intensity on the LED can be changed if we do not supply a fixed signal level to it but a frequency. The duty cycle of the signal determines the light intensity. Write a program that increases the intensity in a linear fashion and the decreases it again linearly.

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The light intensity on the LED can be changed if we do not supply a fixed signal level to it but a frequency. The duty cycle of the signal determines the light intensity. This is called Pulse Width Modulation or PWM for short. Write a program that increases the intensity in a linear fashion and the decreases it again linearly.

Uli Raich - 2020-05-05

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Exercise 4: The WS2812 addressable LED

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Exercise 5: The WS2812 addressable LED

The WS2812 LED is often used in LED chains. It is an RGB LED using a single data line which can be cascaded. It has a data in pin and a data out pin where the data out pin is connected to the data in pin of the following LED. It uses a serial protocol that must be precisely timed. For more information please consult the data sheet

. Fortunatelly a driver for the WS2812

running on the ESP32 is already integrate into the MicroPython binary.

Warning: The WS2812 produces very bright light! Do not look into it directly or reduce the light intensity by software.

The RGB LED chain has 7 LEDs installed on its PCB. Write a program that allows you to find out which LED corresponds to which address. To do so, please switch on a single LED e.g. its red component, and print out the corresponding address. Wait for 5s before you switch on the next LED. Only a single LED should light for each of the seven addresses.

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Exercise 5: Change the Colors

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Exercise 6: Change the Colors

Write a program that consecutively switches on the LEDs in different colors. First switch on the red component of the LED with address 0 then add the one with address 1 etc. Once all LEDs are red, switch them off again, change the color to green and repeat the cycle. Finally do the same for the blue component. Wait for 1 s before switching the LEDs.

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Exercise 7: Change to CCW

In exercise 6 the LEDs will turn on clockwise (cw). Modify the program such that the LEDs turn on counter clock wise (ccw).

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