LED sequence controller without programming

Thread Starter

Gsmgprgsrk

Joined Jun 28, 2017
1
Hellofolks!

Basically what I want to do is I have 32 LED s.So I want that when I press the switch the single LED glows and off one by one up to 4 LEDs then stop. After next press from 5 th to 8 th led should glow like above manner. With a total of 8 presses all 32 should complete and stop. How can I achieve this without programming?
 

absf

Joined Dec 29, 2010
1,968
I did a simple design with 4017, LS138, LS00 and LS93. No MCU or programming required.

C1/R2 is the Power On Reset for 4017 but it doesn't work on proteus. When power is applied, the first 4 LEDs stepped without pressing the STEP button. RESET is used to return the sequence back to column 1.

32LED sequencer.PNG

Can someone please point out my mistakes?

Allen
 

dl324

Joined Mar 30, 2015
16,846
When power is applied, the first 4 LEDs stepped without pressing the STEP button. RESET is used to return the sequence back to column 1.
After the power on reset, CO is HIGH. That inverts the clock until the rising edge of Q5, when CO goes LOW, which forces the CLK input HIGH, and the counter stops advancing.
 

dl324

Joined Mar 30, 2015
16,846
Here's another option:
upload_2017-6-29_20-4-3.png

Can eliminate CD4071 if CD4081 is replaced with CD4011 and the two OR gates are demorganized with the leftover inverters.
 

absf

Joined Dec 29, 2010
1,968
I like the way you use the second 4017 to clock the first 4017. And the way 4013 is used as a RS flip flop and a contact de-bouncer.

I solve my problem by replacing the 74LS138 with 74LS145 and not using the Q0 output. The LS93 is wired as 4 bit counter.

It'd be nice to have a CD4017 with inverted outputs.:cool:

32 LED sequencer 74LS145.PNG

Allen
 
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