Hello,

I am creating a custom mini backlit keyboard.
I found these leds (APA102-2020) which I think do perfect for the job.

The board will have around 100 led! I want to control the brightness as well as the color of each led individually. I am thinking about teensy or something similar. Is it okay?

I found this prototype board for the mentioned led. What confused me was the 4 resistors and 1 capacitor. I am new to electronics and circuits.
All I want is some help on how to put these 100 led on the PCB. Do I need to add a capacitor to each one? How many resistors? Can be chained and controlled by a teensy?

Thank you for your support!

With regards,
Christos Christou.

 

It looks like the resistors on the prototype board are there to protect against miswires and static electricity. They are probably not needed in your application.

The capacitor, however, is needed. It is connected between the VCC and GND pins of the APA102-2020 for power supply bypass. If the LED devices are close together then you may not need one for every device. But, if i were doing it I would plan on one cap per device just to be safe.

Looking at the data sheet it looks like they are daisy chained easily. The limitation would be whether you can update the brightness and color settings fast enough.

 

Take a look at the adafruit dotstar stuff. It uses the apa102. On the tapes there does not seem to be anything but the chip. Based on that, I'd say even the bypass cap isn't necessary. Can't hurt to add one or more but would definitely not use one per chip.

A teensy can handle your application just fine. I noticed there was some discussion of the apa102 on the pjrc forum.

Do you need the full adressability of ata102? RGB? This chip looks like overkill for your needs.