# Beautiful rain drop lights using discrete components.

Joined Sep 28, 2021
266
Hi all,
I saw this chip at here which is able to make beautiful rain drop lights and searched for the datasheet here for its internal circuits. I have searched the web that can do the beautiful rain drop lights using discrete components but could not find any. Does anyone know how to do the rain drop lights using discrete components?

Thank you for reading and have a nice day

#### Alec_t

Joined Sep 17, 2013
14,313
If you're trying to replicate what goes on inside a 74HC595 without using one or more ICs you're going to need a shed-load of components.
This article may give you an idea of the complexity. It shows the parts making up one stage of a shift-register. You would need to multiply that by eight to replicate the 74HC595.

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#### ericgibbs

Joined Jan 29, 2010
18,848
I would go for a homemade electro-mechanical option.

Drive a variable speed Stepper motor > shaft > 8 off phosphor bronze switches driving LED's

E

Joined Sep 28, 2021
266
If you're trying to replicate what goes on inside a 74HC595 without using one or more ICs you're going to need a shed-load of components.
This article may give you an idea of the complexity. It shows the parts making up one stage of a shift-register. You would need to multiply that by eight to replicate the 74HC595.
Wow, amazing these 8-bits technology dates back to Apollo Mission. It's so complex

#### Ian0

Joined Aug 7, 2020
9,814
But if you were trying to create the effect rather than replicate the circuit, a shift register isn’t the way to go.
Make a voltage ramp (series astabLe, two transistors), buffer the ramp (1 transistor) then create a series of comparators (1 transistor each) to drive each LED.
Total 11 transistors, one capacitor, 26 resistors.

#### SamR

Joined Mar 19, 2019
5,040
Chip Complexity: 328 FETs or 82 Equivalent Gates
From the Motorola PDF @ 74HC595 Datasheet catalog
That and all the peripherals would take a lot of PCB real estate. Stick to the chip...

#### Ya’akov

Joined Jan 27, 2019
9,150
I am vaguely imaging a cascade of neon relaxation oscillators and relays, of course, lighting LEDs, the neons are just for the circuit.

#### Ian0

Joined Aug 7, 2020
9,814
I am vaguely imaging a cascade of neon relaxation oscillators and relays, of course, lighting LEDs, the neons are just for the circuit.
How about the neon driving a cathode follower, and then eight pentodes as comparators and constant current sources to drive the LEDs.

#### BillB3857

Joined Feb 28, 2009
2,570
In the old days, I think that stepper switches were used. I was there, but it was a long time ago.

Joined Sep 28, 2021
266
I would go for a homemade electro-mechanical option.

Drive a variable speed Stepper motor > shaft > 8 off phosphor bronze switches driving LED's

E
Hi sir , have you heard of NE 555 flip flop design for 2 led ? Can we combine multiple NE 555 for 4 led rain drop design?

#### Ian0

Joined Aug 7, 2020
9,814
Hi sir , have you heard of NE 555 flip flop design for 2 led ? Can we combine multiple NE 555 for 4 led rain drop design?
View attachment 263905
Probably, but you did say “discrete components”!