Hey there. I'm still new at this but i want some help here. I want to create a pulsing/solid (must be pulsing and switch to solid) led diagram. Ill be using a 9V battery so the voltage must be low. Thanks in advance

 

A couple of 555s and an OP amp will do the trick. (maybe a transistor or thousand…kidding)


Set the first 555 up at the speed you want the pulses, then set the OP amp to read the threshold voltage and use that output to drive the led. (with a transistor if needed)


OP amp is in unity mode and transistor is emitter follower.


The second 555 either sets and resets the first, or overrides the OP amp output. I know there is probably an inversion needed in there somewhere, but I really need to sit at my main computer to work it out.


I’m not at a computer where I can make a diagram, but I’m sure I could whip up something tomorrow, if nobody else posts anything.

 

Hey there. I'm still new at this but i want some help here. I want to create a pulsing/solid (must be pulsing and switch to solid) led diagram. Ill be using a 9V battery so the voltage must be low. Thanks in advance

Thank you!!!! I appreciate it!!!

 

This will give you the idea where to start if you want to try this circuit.

The output is asynchronous. IE: the LED can go steady anywhere during the pulse cycle, if you need synchronous operation possibly somebody else could modify this circuit or provide a better one, unfortunately I don’t have the time right now to work on something that will do that.

The values set for the “pulse” are just a start, they create a pulse something like you might see on a rooftop for air traffic, but you may need to change values to save the battery. IE: bigger resistors and smaller cap.

I didn’t give any values on the pulse/steady times because you didn’t give those. (I think this site has a 555 calculator)

You will probably also want to use CMOS chips, but I never use those so I can’t guarantee they will work here.

The emitter of the NPN can also be placed in the OP amp feedback loop, but the circuit works ok without that. (see notes in the dotted box)

 

Is pulsing full off to full on ?
One way might use 2- 555s, A & B, A is free running at desired pulsing with LED connected between output & + supply. B is a one-shot set to pulsing length with output connected to A's reset. Let's connect B to trigger at power-up ; turning on power: B triggers enabling A which pulses until B times out, LED on until power is cut?

 

The OP did say “pulse” not blink.

Yes if they want it to blink then go steady this is easy to do with only 2 555s.

Set the LED to light on the negative output of first 555 then use a second to control the first with the reset line…the first 555 will go low when in reset and light the diode steady.

And I assumed he wanted the entire cycle to repeat...I could be wrong...

 

The OP did say “pulse” not blink.

Yes if they want it to blink then go steady this is easy to do with only 2 555s.

Set the LED to light on the negative output of first 555 then use a second to control the first with the reset line…the first 555 will go low when in reset and light the diode steady.

And I assumed he wanted the entire cycle to repeat...I could be wrong...

I want a heartbeat led funtion. Ill guess 1 555 will do but if i want 2 settings like 1 press of a button will set it to a heartbeat function and another press wil set it to solid? Will i be using 2 555's???

 

You could do that with one 555 and a on-off pushbutton.

If you wanted to use a momentary button that would involve more.

 

What electrical components do i need to build the circuit that i want???

 

You need to be more clear on exactly you want.

 

Hey there. I'm still new at this but i want some help here. I want to create a pulsing/solid (must be pulsing and switch to solid) led diagram. Ill be using a 9V battery so the voltage must be low. Thanks in advance

Time intervals: R3 - LED on, R4 - LED off.

Edit: Two chips. One chip CD4013, second CD40106. For both 9V to pin 14 (+) and pin 7 (-).

 

Hey there. I'm still new at this but i want some help here. I want to create a pulsing/solid (must be pulsing and switch to solid) led diagram. Ill be using a 9V battery so the voltage must be low. Thanks in advance

Hi

Assuming there is no “steady off” state, you could use a single gated 555 astable so when the output is low the Led is steady on, and when enabled, the led is flashing..

eT