I'm new to electronics so I'm sorry if this sounds stupid.

I recently created an LED sign consisting of 97 LED's on a piece of wood that all light up at the same time when I supply it with 3v. I have watched a bunch of videos on electronics and I saw one that used the 74HC595 shift register to light up an LED sign one by one. (https://www.youtube.com/watch?v=Yexp-I8lzP4)

I came up with a circuit using a 555 timer and 13 shift registers (the photo has one too many) but I'm not sure if it will work and I don’t want to blow up all the chips when I plug it in.

wiring diagram

My question is: Will this circuit work and is there a more efficient way to do this? Also, does the 555 need 5v as I heard it usually drops a couple of volts? How would I reset it a few seconds after the animation has finished?

Any answers are greatly appreciated.


closed as unclear what you're asking by PeterJ, Bence Kaulics, Daniel Grillo, uint128_t, Nick Alexeev Jun 18 '16 at 19:28

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  • 6
    \$\begingroup\$ Can you post a schematic? A graphical breadboard is hard to decipher. \$\endgroup\$ – winny Jun 15 '16 at 20:38
  • \$\begingroup\$ Ah, clivedotcom's script sign. Should be a decent circuit, but I'd be mindful of your overall power consumption. \$\endgroup\$ – supercat Jun 15 '16 at 20:44
  • \$\begingroup\$ Looking at your diagram, though, I only see one wire besides power and ground feeding the 595 chips; you should have a wire to hit shift-clock, a wire to clear all the 595 chips, and probably a wire to hit the register-clock signal (you could double-up with shift-clock, but a dedicated wire would probably be better). \$\endgroup\$ – supercat Jun 15 '16 at 20:48
  • \$\begingroup\$ @supercat sorry the diagram is blurry, the top green wire is the reset one and the yellow one is the clock. \$\endgroup\$ – user114118 Jun 15 '16 at 21:09
  • \$\begingroup\$ @winny Im not at my PC now so I can't post but I'll have to recreate it as I just designed it in breadboard mode, I'll do that tommorow. \$\endgroup\$ – user114118 Jun 15 '16 at 21:11

That is not very smart way to light up a lot leds. Using shift registers with simple 555 is over-killed, and 74HC595 only has 8 outputs.

GO watch my video. Controlling 81 leds with only 2xCD4017 and 1x555 https://www.youtube.com/watch?v=oboLsFuoaL0

To get the effect of a led chaser while driving all led on at the same time, you can use 2x 555 timers, One for chaser effect timing, one for high frequency switching. You can couple them via the reset pin on the timers. To get more interesting effect, such as speeding up/down the led chaser, add another 555 and connect it to pin 5 (control) of your chaser timer.

  • \$\begingroup\$ Could you give me a circuit diagram? Possibly just a scaled down one? \$\endgroup\$ – user114118 Jun 17 '16 at 16:51
  • \$\begingroup\$ you can find the circuit here: engmousaalkaabi.blogspot.com/2016/01/… \$\endgroup\$ – Atmega 328 Jun 22 '16 at 4:45