Which microcontrollers are out there for a LED project?

Other Hardware 3rd Party Boards
1

Hi all,

in my project I have an odd 50+ LEDs doing many different things, like blinking, fading, chasing, flickering and so on. The blinking works on just about any channel but fading, flickering & co need a PWM pin. I do not want to have to do this with an arduino, so I have been exporting the code to an ATtiny85, with the exception of a couple minor setbacks everything is looking very good. One problem that I have with the ATtiny85 is its limited amount of PWM pins. I did some research and found some information about the tlc5941 chip. I am still gathering information but this sounds like the answer that I was looking for 16 I/O channels and I believe all of them are PWM.
Soooo before I go out and buy about 10 tlc5941 chips... My question is, are there any other chips out there that I should consider? anything bigger or better? I guess the only prerequesite is that there has to be a library for it so that I can use my Arduino Uno as ISP. Otherwise, any tips or information links to the tlc5941 chip would be very welcome.

Thanks alot for any advice in advance,
Jason

2

To answer your question, "Which microcontrollers are out there for a LED project?", there is no answer. Any microcontroller can be used, it's how you use it that matters.

Different ways of approaching this:
a) The Mega has 14 PWM channels.
b) Use a serial TLC with gray scale data - the 5941 is one such TLC. The 5940 can drive higher currents if you need it to.

10 of those 5941s will get you 160 PWM pins. You said you have 50+ odd LEDs ... I can only assume they are RGB LEDs since 160 PWM pins is way more than 50+ LEDs.

Another possibility, c), use individual ICs such as the WS2801. One per RGB LED. It has 3 PWM channels, R, G, and B. While they are expensive here in the US, you can get them really cheap overseas, even WITH shipping they are cheaper than getting them in the US at say SparkFun. For that matter, you can get premade and precut RGB LEDs already mated to WS2801s, with wires and all. Just hook up data and clock, provide power and you're good to go. So technically, all you need is a controller that can provide you TWO available pins, nothing else. You don't need PWM pins, you don't need multiple PWM pins, just two pins, digital or analog doesn't really matter, but digital is preferred.

With both the TLC as well as the WS, you just need a data and clock signal to control all the LEDs (if they are all in one long string. If you have multiple strings, then you need multiple data and clocks.) Both of them also have libraries written for them.

You say you don't want to do this with an Arduino, I believe what you meant to say was that you don't want to do this on your Uno board. That ATTiny85 you're using, is an Arduino clone the moment you put an Arduino bootloader on it. That falls under 'doing it with an Arduino' ...

You can built your own clone, or whatever board you want. It's all open source, schematics, design, and all. I built my own clones for all my projects, they are all Arduino clones, running stock Arduino bootloaders. The last time I built a LED project was with two sets of 160 RGB LEDs, each paired with their own WS2801. I did it all in house, didn't buy the premade ones. They do all kinds of fun stuff:

.

3

Hi KirAsh

thanks alot for a VERY informative reply. :slight_smile:

I was just looking for a) confirmation if the TLC is a good choice and b) what other chips may be considered, as there are a massive amounts of chips out there like snowflakes in Alaska and searching for one (usually only having a list of chip names without very good or any description) is like playing "pin-the-tail-on-the-donkey".

I think I will go with a TLC then (at least for this project), the WS2801 that you mentioned sounds very nice, I will have to keep that in mind for the future and do a little research on it.

KirAsh4:
10 of those 5941s will get you 160 PWM pins.

Sorry just a rough number pulled out of thin air, I will probably only need 4 or 5 of them... I like to have more than I need just in case anything happens to get baked during a tinker session and there is always a "next" project where I may or may not need to have them on hand.

KirAsh4:
You say you don't want to do this with an Arduino...

Well, yes I am doing the drydock programming with an Arduino board, but the finished product will run on microcontroller chips alone. for my project (just to get a couple LEDs lit up and dancing in a model) the Arduino board would be a bit of overkill, besides, I am new to the Arduino world and not up to building clones (yet)... which makes you think twice before you put a 20 Euro board in everything.

BTW, it is a little off-topic but I was unable to watch your Youtube vid, Seems the German IP is blocked... says there is music in the video that may be protected by GEMA (the German media rights protection agency)... they have fees for all German citizens for each TV, Radio, Computer, etc to "protect" the rights of the music industry and commercial entities like clubs, cafes or resturants have to pay a large sum in order to be able to play any sort of music (Which is why I think it has a problem with your video, it perceives you as a commercial entity spreading music to everyone and they have not received any $$$ for it). I personally think it is... well not a very nice thing, but that is the one of the prices you pay for living over here I guess.