Which single board to control 60 LEDs?

RE: Which single board to control 60 LEDs?

Problemchild — Fri, 13 Jul 2018 22:39:33 GMT

I was about to put Charlieplexing and maybe an Arduino Nano or at this point any of a dozen controllers.

I see that many of the cheap EBAY clocks use a very small controller and I presume this method so it's a solution already there in the wild. Not to mention Nico's previous answer...doh!

RE: Which single board to control 60 LEDs?

ntewinkel — Thu, 12 Jul 2018 17:41:34 GMT

Hi Andy,

I think what others have already alluded to is the fact that your project cost depends on more than just the controller cost, and there is often a trade-off involved in terms of cheaper controllers often requiring extra external hardware costs (shift registers and addressable LEDs, for example). Also don't forget PCB and labour costs.

At this point, I don't think there are any $1 single-board-computers. But there are some micro controllers that come close. Like Peter said, the ESP8266 is a nice option with plenty of power, and a nice price point - possibly near $1 if you buy thousands at once.

60 LEDs is a lot, but you can control up to 72 standard LEDs by using Charlieplexing and 9 GPIO. You may need to time-share if you need to light them all - ie, flash each of them for parts of a second and our persistence of vision makes it look like they're on (like clock displays do).

So then even an ATtiny84 will do what you need, but I see on Newark even those cost more than a dollar. (maybe less in bulk).

Cheers,

-Nico

RE: Which single board to control 60 LEDs?

Jan Cumps — Thu, 12 Jul 2018 08:50:54 GMT

if all leds are allowed to light up together, and the buzzer can sound at the same time, you may need a separate power supply.

But in essence, any of the cheap controllers + the shifters proposed above (check if the shifters can deliver the load over longer time) can do the job.

RE: Which single board to control 60 LEDs?

NigelB — Thu, 12 Jul 2018 07:40:53 GMT

The best answer would of course depend on what you want to do with the LEDs - Enrico's suggestion above is excellent for low-cost control of an array of simple LEDs, whereas the first two answers are excellent for some much more sophisticated displays - but much more expensive than is suggested by your wish for a "$1 single board computer or controller"... unless you've already burnt your budget on buying the addressable LEDs!

PICs can be very cheap, if you don't mind building your own breadboard rather than buying in a ready-made one - though $1 for a specific requirement that you have in mind may be rather ambitious if that has to cover everything, even as a volume price ...

Hope that helps, if it isn't stating the obvious

Nigel

RE: Which single board to control 60 LEDs?

balearicdynamics — Thu, 12 Jul 2018 07:11:58 GMT

A cheap board means - frequently - few GPIO digital pins. IMHO 60 LEDs are many but not so many...

You can do it with just 4 I/O digital PINs and a bunch of 74HC595 shift-out registers (two of them daisy-chained to every pin). The possible - with a reasonable sense - configurations are:

8 pin -> 1 shift-out register every pin (you need two pins more for signal controls)

4 pin -> 2 shift-out daisy chained every pin

2 pin -> 4 shift-out daisy chained every pint

The video below shows the kind of results you can get (two of these get controlled up to 24 LEDs for few $)

[View:https://www.youtube.com/watch?v=MUtMdPZYCV0:740:466]

RE: Which single board to control 60 LEDs?

Robert Peter Oakes — Thu, 12 Jul 2018 05:24:24 GMT

An esp8266 or ESP32 would work for the controller and this will easily be able to talk to addressable LEDs and drive one or two multi digit 7 segment displays

RE: Which single board to control 60 LEDs?

dougw — Thu, 12 Jul 2018 05:13:06 GMT

It might be possible if you used addressable LEDs, but they would dominate the cost.