Printable View
Hello, I'm a first time builder and had a quick question regarding an illuminated AV switch and the NB v4. I want to have the switch led come on when I remove the kill plug from the recharge port, so after some research I came up with this for the wiring:
Switch Led+ goes to the NB 3.3v pad
Switch Led- goes to the battery-
Is this correct for what I want to accomplish, or would something else have to be done. Any help or pointers are very much appreciated.
This is correct.
You will probably need to put a resistor in that circuit, as most switch LED's forward voltage is less than 3.3v.
Even if the vf of the LED is close to 3.3v, a small ohm resistor is still recommended, as it is cheaper to wire in a <$1 resistor, than have to replace a $8 switch and deal with the disassembly are re-wiring if it burns out.
The "Power Indicator Resistor" section on page 14 of the NB 4 manual covers the resistor calculation.
You can also harvest Positive from the DS pad on NBIV, but that pad is very tiny, and near the MCU...so any mistakes there could kill your board. Grabbing from the 3.3 pad is the easiest way. Your plan is valid though.
Tom
Thank you for the help. Would the 20mA DynaOhm resistor do the job for the switch Led?
It should, you can go directly to NEG on the NB, no need to go "all the way to the battery" with the it.I may have just misunderstood you. Another option, is to wire it off your main LED and itll mimic the blade with the pulses, or, wire it off the DS pad like mentioned and youll know when deep sleep happens.Quote:
Originally Posted by Darth_Kal
Yes, though a resistor is a bit smaller.Quote:
Originally Posted by Darth_Kal