How can i make an led indicator for every output that only lights up when i connect a microcontroller etc.? Is that possible?
If yes, how do i wire it?
Bjerknez:
How can i make an led indicator for every output that only lights up when i connect a microcontroller etc.? Is that possible?
Not really. 
You would need to detect the current drawn by the microcontroller, which may be very small or quite large. To sense current, you need to insert a resistor in series and to sense a small current you need to use a greater resistance value but this will drop more voltage with a greater current and greatly impair the regulation of the voltage.
You need an extra pin in the connector to act as a "tally" and operate the LED.
Paul__B:
Not really.You would need to detect the current drawn by the microcontroller, which may be very small or quite large. To sense current, you need to insert a resistor in series and to sense a small current you need to use a greater resistance value but this will drop more voltage with a greater current and greatly impair the regulation of the voltage.
You need an extra pin in the connector to act as a "tally" and operate the LED.
I see. It makes sense. 
Using an three pin connector for that seems a little drastic.
You could negate the problems with regulation by placing the current shunt on the input side of each buck converter.
That still has the problem of detecting a large range currents - the current draw can easily be as little as a few mA or as much as 1-2A in case you add motors (current as on the output, proportionally lower on the input).
Bjerknez:
I see. It makes sense.
Using an three pin connector for that seems a little drastic.
There are connectors that open/close a switch as you plug it in, such as those found in many female 5.5mm jack connectors. That doesn't tell you something is connected and drawing power, just that something is plugged in.
Hi,
Can I, as previously suggested, put LED indicators on the INPUT and EACH of the OUTPUTS to provide a quick visual indication of your PCB performance.
You need to know if it is turned On or not when you got to connect your projects or change a component.
Never do circuit mods with power connected. (Murphy lurks everywhere)
Also you need a fuse on the power input side of your PCB.
If you are using a laptop powersupply and only powering circuits that each max out at 2 to 3 Amps, if you have a short on your PCB the power supply will put many amps into the short.
One of the possible outcomes will be your project you are powering will also be destroyed.
Tom...
Thanks for good advice Tom
I thinking to but some SMD fuses from AliExpress. But when i search the words "SMD fuse" i get theese results:
https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20210207054210&SearchText=smd+fuse
What should i choose?
resettable fuses, termal fuses?
I do not want fuse that are smaller than a 1206. It can without problem be a little bigger too.
I want to buy som good "allround" fuse values for PCB work that do not take up a lot of space. But what type of fuse is recomended?
Through hole, Surface mount etc.?
Hi,
Is there a reason you are worried about space?
Use M205 fuses and PCB fuse holder clips.
Or resettables, but make sure they work for your voltage.
Tom...
Thanks.
No other reasons that i just want it to not take much space.
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