NBV3 Schematic check please

[Count Voodoo]

Hey guys! I am in the process of my first build and I have been reading and reading trying to understand how all this works for when I get one of these boards in my hands. I am planning my build with the Tri-XP-E2 in RB/RB/W Parallel with W being FoC. I made this schematic with the fact in mind that this card has an on-board PEx. Ive read the new manual online a few times, hope I am not missing anything. Just curious if you can take a look at this and let me know if my plans are sound...no pun intended! lol I have never made a schematic so forgive me if its wonky. Your thoughts are welcomed and appreciated!

Voodoo

http://i1124.photobucket.com/albums/l575/jessdog81/Saber%20Schematic.jpg

[Jay-gon Jinn]

That looks correct to me.

[Count Voodoo]

Awesome! Thank you for taking a moment to look it over! I am sure these get put on here over and over and it must get old having to figure out everyones stuff so i appreciate it! I wont touch this build until I understand every aspect so I had to manually make my own schematic to test and grow my understanding. Thanks again!

[Miraluka]

I haven't read the new V3 manual yet so I haven't looked at how the onboard Pex is wired, but the rest looks good.

Nice diagram, too. Easy to read/follow. Good work.

[bunger]

When is the v3 supposed to come out?

[Forgetful Jedi Knight]

It *should* be out by the end of the month or so.

[Count Voodoo]

I haven't read the new V3 manual yet so I haven't looked at how the onboard Pex is wired, but the rest looks good.

Nice diagram, too. Easy to read/follow. Good work.

Thanks Miraluka! I am trying my best to put the work in and not be that noob that just wants everything done for him! Everyone has been great though for the few silly questions I have had! I am actually having so much fun planning this build and learning!

[JWLaRue]

I would appreciate it if someone could check my calculations for the power resistors for a NBv3 and Tri-CREE LED combination! I used the guidance in the NBv3 manual and am assuming the same wiring set-up as Count Voodoo's diagram.

LEDs: two royal blue with a forward voltage of 3.41v @1000mA and one white with a forward voltage of 3.15v @1000mA.
Battery: 18650 (?)

Calculations:
royal blue LED resistor = (3.7 - 3.41) / 1.0A = 0.29 ohms
resistor wattage = (3.7 - 3.41) * 1.0A = 0.29 watts

white LED resistor = (3.7 - 3.15) / 1.0A = 0.549 ohms
resistor wattage = (3.7 - 3.15) * 1.0A = 0.55 watts

-thanks, guys!

Jeff

[Jay-gon Jinn]

I would appreciate it if someone could check my calculations for the power resistors for a NBv3 and Tri-CREE LED combination! I used the guidance in the NBv3 manual and am assuming the same wiring set-up as Count Voodoo's diagram.

LEDs: two royal blue with a forward voltage of 3.41v @1000mA and one white with a forward voltage of 3.15v @1000mA.
Battery: 18650 (?)

Calculations:
royal blue LED resistor = (3.7 - 3.41) / 1.0A = 0.29 ohms
resistor wattage = (3.7 - 3.41) * 1.0A = 0.29 watts

white LED resistor = (3.7 - 3.15) / 1.0A = 0.549 ohms
resistor wattage = (3.7 - 3.15) * 1.0A = 0.55 watts

-thanks, guys!

Jeff
Your calculations for the resistors is right, but your wattage calculation looks wrong to me...the formula is: P <Watts> = R * I^2 Your numbers are: P=0.29*1^2 which equals out to 0.29 watts...you'd need a 1/2 watt resistor for those. The white works out to be a 0.549 watts, so you'd likely need to round up to a 1 watt resistor for that.

[JWLaRue]

Thanks for the review....very much appreciated.

I'll re-check the NBv3 manual for the wattage calculation, sounds like it may be incorrect. :)

-Jeff

[Generic Jedi]

There are three different equations you can use to find the wattage rating for a resiter. If you use the correct values in the correct places, they will all give the same answer.

P = power measured in watts
E = voltage measured in volts
I = current measured in amps
R = resistance measured in ohms

Equation 1: P = R x I^2
You take the resitor value from the resitor equation and multiply it by current squared.

Equation 2: P = E x I
You take the voltage (that's voltage supply minus LED voltage forward, just like in the resistor equation) and multiply it by current.

Equation 3: It uses the values for E and R to find P, but I don't remember the equation. I'll have to look it up when I get home.

[Generic Jedi]

Say you wanted to find a resistor for an accent LED that has a forward voltage of 3 volts to run at 20 mA. You use a 3.3 volt pad to power it.

For the resistor: R = (supply voltage - forward voltage) / current
That gives you: R = ( 3.3 - 3 ) / 0.02 = 15 Ohms

To find the wattage
Equation 1: P = R x I^2
Or : P = 15 x 0.02^2 = 0.006 watts

Equation 2: P = E x I
Or: P = ( 3.3 - 3 ) x 0.02 = 0.006 watts

You would still have to round the watt value up to a resistor you could actually find...

[Generic Jedi]

The third equation is: P = E^2 / R
E is voltage supply minus forward voltage: P = (Vsupply -Vforward)^2 / R

That gives us: P = ( 3.3 - 3 )^2 / 15 = 0.006 watts

[Count Voodoo]

The question I have now is silly, but its another tiny detail I am having trouble finding. If you look at the junction from the Momentary switch black wire to the Negative line going from the Recharge port to the Board Negative pad, do I just solder that at the negative post on the recharge port or straight to the board negative pad with the negative wire from the recharge Port? That would seem to be the same anyways, but I want to do it correctly when I do finally get the board. Thanks!

[Silver Serpent]

Whichever is easier for you. I find it's more difficult soldering a bunch of wires to the pad on the board, so I opt for the other method.

[Count Voodoo]

Ok great , thanks for the input SS! I figured it was most likely the same, but youre right, the more space I can free up on the pads the better!

[erlomd]

great wiring diagram!

but, I was told that resistors for each LED are not needed when connecting to the NBv3?

[FenixFire]

http://http://www.plecterlabs.com/Media/Doc/Nano%20Biscotte%20v3-GB.pdf

Check page 9.

[erlomd]

http://http://www.plecterlabs.com/Media/Doc/Nano%20Biscotte%20v3-GB.pdf

Check page 9.

I did...but on page 21 of the NBv3 manual it says & I quote:

"On the one hand, such a small resistor is unpractical to source and tolerance will not
lead to an accurate current limitation. On the other hand, not using a resistor will
overdrive the LED which might fry. The board driver can act as a linear, configurable
resistor, using the drive parameter. When getting such a small resistor value (below
0.5 ohm, AND Vled < Vcell), the drive can be calculated as follows:
drive = 1023 * (Vled / Vcell)
in our case, drive = 1023 * (3.45 / 3.7) = 954
The drive parameters can be also fine tuned using an amp-meter in the high-power
LED circuit: adjust the drive until you reach the exact average current required for
your LED. Never set the drive under 80% of the maximum value."

[Forgetful Jedi Knight]

Always use a resistor!!!

[erlomd]

ok ok...jeez dont pull a kylo ren on me here...lol

[Greenie]

Resistor = 50cents. Tri-Cree = $20.

[Silver Serpent]

Yep. And when you don't use a resistor on the NB, you come back here asking why the sound board is giving you constant swing/clash sounds.

The drive parameter is "OK" for fine tuning a SINGLE die (I'd still use a resistor). When you're running two dice on a Tri-LED, you're just going to run into trouble without resistors.

[erlomd]

Got it...resistors are cheap and effective...so
for my 2 blue tri cree: 1.8ohms, 1/2w (each)
for the single white tri cree: 1ohms, 2w (single)

[CET]

Blue LEDs usually have similar power requirements as white ones, so you can usually just put them all on the same resistor. I use 2w/1ohm resistors for them, and I keep a bunch of them in my stash.

[oldgamefreak]

So CET you just use 1 single resister for all 3 dies, correct? I'm starting to amass the parts to do the same and was looking at the same colors.

[emperor Vader]

do the resistors go on the positive or the negative? or does it not matter? I've scene a video tutorial where they put it on the negative but then I've seen a wiring diagram where they put it on the positive.

[Greenie]

Pos or neg. it doesn't matter :)

[Silver Serpent]

That's correct, they can go on either side. My advice: pick one, and be consistent.

One exception: the DynaOhm resistors MUST go on the positive side.