Light chaser with 74hc595 and individual led fading

Projects Programming
1

I would like to make a light chaser with the 74hc595 and let it run in a kind of wave. The first led is faded and getting brighter and brighter.
The whole thing should be realized with a shift register, because I want to drive many leds so.
I have found this program (including video) for Arduinocontroller like the Uno here -> ShiftRegister PWM Library – Timo Denk's Blog

It is about synchronizing the interrupts of the timer with the frequency of the ESP. However, I am not so deep in the programming that I could realize this alone for the ESP8266, so I hope here in the forum are a few people who can help me with this program.

2

I did not check the library but I have a feeling that it will not scale too well. You can consider Adafruit 16-Channel 12-bit PWM/Servo Shield - I2C interface.

You can go up to 992 leds.

3

thanks for the tip sterretje!
But for my application, the resolution donnot have to be very high .. I would use it only for a decorative lighting.

4

Using the 74HC595, you will not be able to dim the leds individualy. All the 8 of them (thru the OE pin) only is possible with this chip.

Jacques

5

yes i know normaly all leds could be only dimmed together ... but this guy used a 74hc595 for his example and it workes. Here the videolink:

"The ShiftRegister PWM Library enables usage of shift register pins as pulse-width modulated (PWM) pins. Instead of setting them to either high or low, the library lets the user set them to up to 256 PWM-levels."

in the article he describes it how he did it over a timer and interrupts to individualy address the leds.

6

What is the relation betweeen this Library and the ESP8266?

7

This program example is written for an Arduino Uno ... it's not compatible for the ESP8266 unfortunately. The timers are totally different so I´d ned a different ISR.
For me it´s not easy to rewrite the code.. I am still in a learning prozess and hope to find someone who can help.

8

I see. At this point, it is also over my head. Someone else will have to help you on this.

Wish you success.

Jacques

9

You may want to consider using the ws2812 addressable leds. The neopixel library suports the ESP8266.

10

Yes i know the ws2812b Leds .. they are very flexible and individuel addressable ... but they need to much power and the leds are much to big for my project. The decorative lamp should also (if its´s possible) be supplied with batteries. Therefore the solution with a shiftregister would be the best way I tought.

Or knows somebody an other solution?

I have read about a project called CryptoIO..there it should also be possible to use 32 PWM ports wih a 74hc595 on the ESP8266. So far I have not been able to try the code yet. -> GitHub - Crypter/CryptoIO: Get 32 outputs from ESP8266 boards using shift registers and I2S
Does someone know something about this?

11

Have a look at post #3 in this thread
https://forum.arduino.cc/index.php?topic=529680.msg3610743#msg3610743
It can be done.