LED strips for seven segment display clock

Projects General Guidance
1

Hi,

I’ve been researching the feasibility of creating a clock out of LED strips in a seven segment display fashion. I realized I hadn’t thought it through however because there aren’t nearly enough pins on an Arduino to drive each strip. By my reckoning there would be at least 29 separate segments including the colon between the hour and minute displays. For this project I’m using 12 V RGB LED strips with six LED‘s per segment.

I plan on using 16ga speaker wire to power the positive and red leads of each strip. I read some people were using level shifters that can each address I think 8 channels each. I’m not quite sure how to connect the power to the led other than using a transistor to connect the power. I think I’m a bit over my head but still working on getting it figured out.

Does anyone know if someone has done anything similar? I’ve found a few projects but they all seem to be using WS2811 led strips.

Thanks for any advice in advance!

2

Easily done with one TPIC6B595 shift register per digit.

Google “Arduino TPIC6B595“ and you’ll find everything you need. If not, ask.

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esteed:
I’ve found a few projects but they all seem to be using WS2811 led strips.

For a good reason.
Addressable RGB strips don't need additional hardware.

Two sections (cut lines) of a 12volt RGB strip draw about 40mA per colour.
Could control/switch that with a TPIC6B595 shift register.
Problem is that you need 12 of them, that could easily end up in a cobweb of wires.
Leo..

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"I plan on using 16ga speaker wire to power the positive and red leads of each strip. "

So these are strips with +, and R, G, B contacts, and you are only using R?

Then TPIC6B595 would be the way to go. 6 LEDs per segment would use ~ 40mA/segment. Each output can sink 150mA.

I offer a board that supports up to 12 of the chips and has a 328P for controlling them. Plug on an FTDI Basic or equivalent for programming it.

http://www.crossroadsfencing.com/BobuinoRev17/

1741×1669 662 KB

Here the board is driving an 8-digit test board I have with 3 and 6 LED segments.

5

There's another way, if I'm correct in understand you're just trying to build a supersized version of a display like this:

Those can be controlled using a MAX6958 or TM1637 driver IC, communicating over I2C. Of course you'd need power drivers for each LED strip, as those chips are designed to run single LEDs, not complete strips.