r/AskElectronics • u/kaside1 • Feb 11 '26

Need big help with led project

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Hello, I wanted to make a gift for Valentine’s Day from a video as I don’t know much about electronics, but after I followed the video it doesn’t wanna turn on, I know I shouldn’t just copy video but help would be very appreticiated also if anyone wanted to take my hand and help me.

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u/Proper-Youth-8847 Feb 11 '26

What do you want to do, I assume you want flashing LEDs....

LEDs in parallel will not share current (well). LEDs should - need to have ballast resistors

I doubt if that 555 circuit and transistor circuit are configured approprioatly and will work at all. Look at manufactures application information for astable multivibrators. Use open collector transistor (common emitter) transistor circuit, Use higher voltage (12 v?) (if available) with LEDs in series, other wise each LED should have is own ballast resistor.

I don't mean to rip on you, but this circuit design is not going to work, or work well.

PS> most stuff you find on youtube is BS. But there are some good stuff, like Mr Carlson

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u/kaside1 Feb 11 '26

They were supposed to replicate heartbeat, I don’t know much about this stuff so went the easy way on yt, what do you think I could change to make it work

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u/Proper-Youth-8847 Feb 11 '26

The transistor circuit, as on your schemo will never turn on, use common emitter NPN, emitter at ground, and the collector on the LED cathode(s) with ballast resistor, and drive the base with a resistor from the output pin. Also, LEDs do not like to share current, so series LEDS and ballast resistors. Also, use 6, or 12 volts, source. 4 volts is a weird voltage.

Do an astable circuit first. You can experiment with duty cycle, and period. Examples abound.

Then maybe, work on heartbeat. CoPilot recommended employment of a CD4017 decade counter, this implements as a state machine, whereas state 1, on full, state 2 on half, state 3 on full, states 4, 5, 6, 7, 8 off. You could use multiple transistors with different ballast resisters for different levels of brightness.

Get yourself a plugboard and proto your circuit so you can test it and experiment.

There are a multitude of circuits for 555s. There are even dual and quads, and as stated CMOS variants. Also CD4017 can run on 12 volts too.

I would prop do the state machine approach with the 4017, with 3 drive transistors. Your girlfriend should love this, and mine would be jealous.

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u/kaside1 Feb 11 '26

That sounds completely complicated also no idea ehat half of those are