4 X 8-32 LED Chaser

Thread Starter

Icanmakeit67

Joined Sep 23, 2018
97
I keep looking but from experience I find so much success here. I believe this is pretty basic so here it is. Imagine a circle of 32 LEDs. If displayed/spaced correctly 4 of the LEDs one at each cardinal direction, will be present. I’d like the 4 LEDs at these locations to go on then the next 4 to the right of those 4 just lighted to go on etc, around the circle continuing while powered. A 4 LED chaser. To reiterate 4 on then off, next 4 to the right on then off, etc. I also want to control the speed of the effect.
Any help welcome, Thank You
 

Audioguru again

Joined Oct 21, 2019
6,701
A microcontroller or a CD4017 is usually used as a chaser. 4 parallel LEDs will need a transistor for driving their current. Any clocking oscillator can be used.
 

Thread Starter

Icanmakeit67

Joined Sep 23, 2018
97
I get your suggestion…. Could I get a pointer of how the output from the 4017 is going to a transistor?
I’m thinking an output from the 4017 goes to base of 2N3904 then emitter to anode of led then collector to Vcc. Cathode of led to ground. 4 parallel LEDs off one transistor. Not positive if transistor base need a current limiting resistor? ?
 

dl324

Joined Mar 30, 2015
16,935
I’m thinking an output from the 4017 goes to base of 2N3904 then emitter to anode of led then collector to Vcc. Cathode of led to ground. 4 parallel LEDs off one transistor. Not positive if transistor base need a current limiting resistor? ?
1708285546894.png

EDIT: CD4017 can't actually source 4mA, but I did saturation tests on two randomly selected (and 5 other types) and all saturated at higher assumed betas.
 
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