This is an idea for my Firestarter project. (See signature) I'll have 5 LEDs at the front and a switch. The LED on the right won't be included in this circuit/idea. What I want to do is to enable or disable the 4 LEDs on the left side with the switch that's on the right side. For that I got a 4066 which I want to enable/disable those 4 LEDs at the same time just using that switch. I'll wire the switch to the control pins and then each NIC and HDD signal to the input and output. Do I need to use any resistor or can I wire everything directly? Will I need a pull down resistor after the switch? Is 47K ok? Can I use just a 47K for all the control pins or do I have to use a higher value like 100K? Here's a schematic.
dont quote me on this but the chip says it can work upto 18v so i doubt you need a pulldown resistor on the control lines, and since the inputs are comming from a place where a LED was sopposed to be placed anyway, a doubt you need any resistors there. Just get experimenting, start with 100k on the leds and controls and work down till it all works!
The pulldown resistor after the switch would be use to give a reference voltage to the IC when the circuit is opened, that reference would be GND. I think that without that reference the IC wouldn't know what to do. But I'm still asking because I've never worked with this IC before. About the IC's voltage and resistors, my questuion is that if the incoming voltage is the same as the outgoing voltage or if the IC supplies 12V at the output.
Forget about the pull down resistor, I just found a DPDT switch, so I'm going to use 12V and ground. I want to use a 4066 because I already have one. This is what I want to do. Is this ok?
Not really. With the HDD activity header, one pin is usually connected to +5V through an LED resistor, other pin to collector of an NPN transistor switched on by drive activity. You could use a bank of PNP switch transistors, with a common 5V supply controlled by the master switch. I don't know how NIC LED headers work, but optoisolators would cover all bases. A maybe minor problem with the 4066 is the highish 'on' resistance, will dim the LED slightly.
About the dim LEDs, well, I'm not going to use ultra bright LEDs, just the normal ones, so I don't think that's going to be a problem. Right now all I want to know is if that last schematic is ok or if I'm missing something.
I'd add a resistor between the switch and the control pins (using 4) so it limits current to the control pins. Check the datasheet for the drive current needed.
I see... Having read the project page, maybe you can do without all the crap that I added... Just make sure that you don't need a resistor for the LED, and you could get away with this instead: (Yes, this is our original circuit, with the correct symbol) Sorry for all the confusion LA Greg
You still need a pulldown resistor on the control pin Lardarse. 47k should do fine - just don't let it float
