I think you’d better share the circuit diagram. Even a screenshot of the simulation will work.
The problem is that it might not be worth it for you to simulate this. Setting up a simulation that tells you exactly what happens is nontrivial. It has nothing to do with kicad itself, but rather the sheer amount of unknown dimensions you have.
You would be much better off taking the led connector off the motherboard, connect a new wire set into it and connect that into a breadboard, then connect a resistor in parallel with what you have now and see what happens. Then wire a switch so that power line goes trough resistor or not. Now you have a switch. Replace switch with transistor change switching form humans switching to other input.
If you get it working then just put the stuff on the wire harness and your done.
See the diagram supplied before by paulvdh
The part that answered my question about how to set up the simulation.
Sorry, I hadn’t noticed that part before. Well, they’re diodes. Let a current run through the LED and it will emit light. Use resistors to limit the current. Anything else relevant for my problem?
Maybe not. But a good exercise nevertheless. I expect other simulation tasks in the future. And the schema editor of KiCad is a lot more usable than that of LTSpice from the 1970s (but you knew this already).
But you’re right, this is actually taking more time than estimated. I’m probably better off finding a nicer sticker. This problem is too complex and not worth solving.
So the problem is that you have to have a idea of the schematic you need before simulating. Simulation comes after designing, not before it. Its easy to simulate something harder to get meaningful answers!
Above is something. No idea about your led values no idea how your led converts that to meaningful visually pleasing values.
NOTE the diode pins are reversed to what the simulation expects.
I agree with putting a nicer sticker on your PC, but that does not mean you should abandon this project completely. Getting to design “something” and getting simulation working is a curve you have to go through no matter what the project is, and you have to learn how to configure things such as that Vpulse source that joolala posted a screenshot of.
@joojala Can you zip up and post that simulation here for ygoe? It may help him in getting something to work. It’s always a lot easier to get started when you can modify a working thing then having to set up something from scratch.
(Also: When you put 2 or three “regular” diodes in series, you get a good enough approximation of an LED for most practical simulations).
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Here is the project i used for simulation
simulate_dimming_light.zip (6.4 KB)
By the way you can configure the vpulse via the properties window → Simulation model editor in a way that is a bit nicer than writing the values yourself.
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Apart from Simulation/etc - Amusing myself but, it may be of Slight interest…
Typical LED Blinking (using 500ms On/Off). It’s enough Cap charge time and discharge time to exchange Resistor and Cap for testing. [Used Arduino, First part is hard-wired (no Cap) Second part uses the Cap]
I used 1kΩ Resistor and various Cap’s. 1000uF/16V electrolytic cap worked well…
(Ignore all the wires, has nothing to do with this…).
The point of this is that Cap’s charge and discharge is enough to Light LED On/Off thus, a geek could affect Brightness by using a selected/tested Cap and Resistor…
Greetings;
I have a similar problem with an HDMI splitter box, whereupon the LEDs are so bright they’d be useful in top of a lighthouse.
I fixed this problem by sticking an appropriately sized piece of plain white paper over the LEDs. No need for faffing about with all sorts of other solutions - dead simple and quick.
Give it a try - you’ve got nowt to lose.
Cheers
Ok, here is the circuit I had in mind. It uses an optocoupler so is insensitive to the actual configuration of the LEDs w.r.t the motherboard, just have to get the polarities correct on both sides. The left part of the optocoupler replaces the HDD light and the resistor is calculated to pass the appropriate current through the LED. The right part of the optocoupler is wired in parallel with the power LED to shunt enough current to dim it a little. The resistor values have to be calculated using the optocoupler specs, or at least ascertained experimentally (I could not label them like R1 and R2, this drawing was done in Falstad, which I find useful for simulating simple circuits).
This is not a simulation problem! You cannot simulate before you have the circuit design set down. Trying to create a design by futzing with a simulator is like trying to learn bookkeeping by playing around with a spreadsheet.
Since this an electronics design problem and is outside the scope of KiCad forum, this is the last word I will say on this topic.
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