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whitmers
10-17-2012, 06:13 PM
Man, this board is so much smaller than I expected. It's pretty awesome.

In this experiment of mine, I see that it asks for 1 cell lion, if I get a two cell holder and use a dummy cell, will that get me the same result effectively?

Also, would using a BuckPuck 1000mA, be better than using a resistor?

FenderBender
10-17-2012, 06:20 PM
What LED are you using?

Most pucks don't work with less than 5V

whitmers
10-20-2012, 06:01 PM
Not sure, I think its 5w, I'll find out when i get inside.

Since this board is esd (I'm still new to it), are people using an anti-static wrist strap or anti static mats? Does it matter?

Forgetful Jedi Knight
10-20-2012, 06:46 PM
In my opinion, using a buckpuck would NOT be better in this case. Also depending on which color LED you have the resistor you need could be minimal, as the blues, greens, whites are close to the voltage of a single cell battery (3.7V)

Also if you search around for an 18650 single cell holder, you can use that with your NB depending on your saber design. ;)

whitmers
10-21-2012, 02:34 PM
could using a dual holder/ speaker combo with a dummy cell work? I was initially planning on using a dual lion 14500, then upon closer inspection thought that using a single 14500 + dummy cell would work.

Forgetful Jedi Knight
10-21-2012, 02:37 PM
could using a dual holder/ speaker combo with a dummy cell work?

Yes. But again, your run time will be less with 14500's vs. an 18650.

Machinimax
10-21-2012, 05:08 PM
In my opinion, using a buckpuck would NOT be better in this case. Also depending on which color LED you have the resistor you need could be minimal, as the blues, greens, whites are close to the voltage of a single cell battery (3.7V)

And if that resistor value is small enough (less than 0.5 Ohms), then you can you can use the Drive feature on the board and not need the resistor at all. But like FJK said it will depend on how much voltage your led will need. See pg. 17 of the Nano manual for more details.

whitmers
10-21-2012, 08:21 PM
its purple so red and blue I guess, and the LED is from an older ultra saber

Caine Drathul
10-22-2012, 02:22 AM
its purple so red and blue I guess, and the LED is from an older ultra saber

With that particular LED and the hilt it was pulled from, I am guessing it was originally powered by 6V. So in that case, because the NB is only meant to take a 3.7V battery, you are not going to get the same purple that you did when it was powered by 6V. You are going to have to experiment to get it to the color that you want.

whitmers
10-29-2012, 06:56 PM
I learned one powerful lesson so far... that the quality of the soldering iron can make a big difference. I hope I haven't irrevocably gummed up my board with solder since it dribbled in the wrong spots. bleah.

Darth Odious
10-31-2012, 05:54 AM
Is a resistor even necessary if you're straight up using only drive parameters?

Xevious
10-31-2012, 06:45 AM
You use one or the other.

The "drive" parameter tweaks the voltage to the led, so you'll generally use that when the forward voltage of the LED is close to the battery voltage.

If your calculated resistor value is less than 0.5 ohms, then adjust the drive level with the formula "drive = 1023 * (Vled / Vcell)" and omit the resistor. If the forward voltage of the LED is much smaller than the battery voltage, then use a physical resistor using the formula “Resistor = (Vcell – Vled) / LedCurrent”.

So, if I’m using a 3.7V battery powering a LED with a Vforward of 2.3V and forward current of 0.7amps, my required resistor is 2 ohms. I leave “drive” at 1023 and install the resistor. If instead I want to use a LED with a Vforward of 3.4V, I forgo the resistor and set "drive" to 940.

Darth Odious
10-31-2012, 02:47 PM
You use one or the other.

So, if I’m using a 3.7V battery powering a LED with a Vforward of 2.3V and forward current of 0.7amps, my required resistor is 2 ohms. I leave “drive” at 1023 and install the resistor. If instead I want to use a LED with a Vforward of 3.4V, I forgo the resistor and set "drive" to 940.

I get that, In your example it looks like you're using a Rebel Red (3.7-2.3) / 0.7 = 2ohm (Resistor For Rebel Red @ 700mA)

I was wondering if it were possible to forgo the 2 ohm resistor completely and just set the Drive Parameter to 636. (1023 * (2.3/3.7) = 636) Using the same Rebel Red as an example.)

Xevious
10-31-2012, 03:27 PM
I was wondering if it were possible to forgo the 2 ohm resistor completely and just set the Drive Parameter to 636. (1023 * (2.3/3.7) = 636) Using the same Rebel Red as an example.)

I would not do that because in that example the resistor is dissipating 1 Watt. Power dissipated = Voltage drop x Led Current. So instead of dissipating that Watt across a resistor, you'd be asking the precious NB to do it instead. (In fact, I'd derate that resistor by 50%: use a 2 Watt resistor and never, ever have to worry about it.)

The "drive" setting trick works because the voltage drop is small. To return to the above example of a 3.4V LED, it would probably be on the blue side, so let's say it burns 1A. That's only 0.3 Watts, which appears to be in the neighborhood of whatever Erv has designed it for. The NB manual says to use the "drive" setting if you're using 0.5 ohms or less -- assuming a 1A led current, that means he'd rated the thing at 0.5 Watts max.

whitmers
11-01-2012, 06:38 PM
I've got it together and it works! I went with the resistor. Learned a lot here about sabers from you guys and I learned a whole lot about soldering and wiring. Thanks a bunch! As it is right now, I am using with a dual battery holder using a one 14500 Lion cell and one dummy cell. I looked that the NB installation and it asked for one cell, so...since I have a dual cell holder, will it be more than the board can handle if I fill it with two 14500 Lion cells?

DarthAlice
11-02-2012, 03:54 PM
I've got it together and it works! I went with the resistor. Learned a lot here about sabers from you guys and I learned a whole lot about soldering and wiring. Thanks a bunch! As it is right now, I am using with a dual battery holder using a one 14500 Lion cell and one dummy cell. I looked that the NB installation and it asked for one cell, so...since I have a dual cell holder, will it be more than the board can handle if I fill it with two 14500 Lion cells? Too high a forward voltage youll make it crispy! Why not wire the 2 batteries in parallel to keep the 3.7 volts and double your run time? it's not to hard to do with a double battery holder ( I have an NB as well and a good soldering station (makes a ton difference) and am currently planning on installing it in a katana build with 2 14500 in parallel

whitmers
11-03-2012, 07:28 AM
I think that is what I initially wanted thought would happen, then the NB asked for one. What you mention is exactly what I want to do. What should I do to make this dream reality?

DarthAlice
11-05-2012, 03:18 AM
Too high a forward voltage youll make it crispy! Why not wire the 2 batteries in parallel to keep the 3.7 volts and double your run time? it's not to hard to do with a double battery holder ( I have an NB as well and a good soldering station (makes a ton difference) and am currently planning on installing it in a katana build with 2 14500 in parallel I know people say not to dothis with a battery holder( I normally just make up a 2 cell pack by soldering a lead to the 2 hot poles, and a lead to the 2 ground poles, from there you have 1 lead soldered to each end giving you 3.7 volts with lotsa runtime some 1" heatshrink and voila! a pack(I put 4 18650's in parallel in my protosaber, with math that adds up to 4x 2400MA - 9600 ma which as mentioned before is just your runtime, think of a car battery they come in many diiferent CCA or cold cranking amp ratings....same idea) for a 2 place battery holder it takes a bit of cutting and modding,that last one I reworked, I just very carefully removed the spring from the top, soldered a black lead wire to it, and cut off the black lead from the holder, and then a small rivet and washer to secure it to the existing hole/lead on the bottom of the holder, now the batteries can only be installed with the + up, now that both springs are on the bottom, this now makes it a parallel battery holder in that the 2 grounds are now connected as well as the 2 positives with a dedicated wire for each.(hope that made sense)

whitmers
11-05-2012, 07:47 AM
That looks and sounds pretty neat. I might give that a try. I'll try it on the next beast I attempt to make, probably for my son's seventh birthday.Thanks!

jedimastergarcia87
11-15-2012, 10:06 AM
I'm also wondering because I will be using a P4 green and a single 18650 or 14500 whichever is better...

Silver Serpent
11-15-2012, 10:52 AM
If you have room for it, the 18650 will give you longer runtimes. Both will give you the same brightness.

psab keel
12-22-2012, 12:30 AM
Does the Drive parameter yield a consistent current like a typical driver would, or will it fluctuate? In other words, if the LED is set to 1000 mA with the drive parameter, then the current can never exceed feeding 1000 mA to the LED? I guess my questions relate more to how efficient this setting is, vs having a resistor or even a micro puck driver in the design in terms of regulating the LED current.

Darth Scorn
12-22-2012, 08:09 PM
I know a p4 red can be ran at 3v max it says in the shop, but would I be asking to much to not have to put in a resistor and run it on the 3.7v?

Forgetful Jedi Knight
12-22-2012, 08:25 PM
I know a p4 red can be ran at 3v max it says in the shop, but would I be asking to much to not have to put in a resistor and run it on the 3.7v?

Yes, you would be asking too much... WAY too much. Put a resistor on it, just to be safe. The specs as I remember them had the lower end of the Vf at around 3.1 - 3.2.

Darth Scorn
12-22-2012, 11:51 PM
cool thanks better be safe than have a fried led

whitmers
01-06-2013, 10:28 AM
my next plan is to rewire the speaker holder to run two 14,500s in parallel so that I can consistently use the same type of power cells as my other sabers. While I am going inside the saber again, has anyone use the nano biscotte's led slot for illuminating a crystal chamber yet?

jedimastergarcia87
01-10-2013, 01:18 AM
I'm wondering if a resistor is needed if you do a P4 green and a single 18650. I saw the new pre-wired Nano Biscotte so I may give it a whirl.

Silver Serpent
01-10-2013, 06:04 AM
You can get by without a resistor with that setup JMG.

Captain
01-10-2013, 05:47 PM
Could I do without a resistor with a white rebel star LED? And if I do not use a resistor will I have to change the Drive parameters?

Silver Serpent
01-10-2013, 06:22 PM
If the voltage of your battery pack is equal to, or slightly less than, the forward voltage of your LED, then you will not need a resistor.

With a single li-ion, your battery voltage is 3.7 (up to 4.2 when fully charged). White Rebel has a Vf of 3.1v, so you'll need a resistor. The Seoul P4 green has a Vf of 4.1v, so a resistor is not necessary.

Changing the drive parameter is good for fine tuning, but a resistor is the better way to adjust if you have a significant difference in power between your LED and battery pack.

Captain
01-10-2013, 06:48 PM
So with the 18650 and the White Rebel star I figured I need a 1ohm 4 W resistor so I figure a 1ohm 5W resistor should Do am I right?

Forgetful Jedi Knight
01-10-2013, 07:03 PM
So with the 18650 and the White Rebel star I figured I need a 1ohm 4 W resistor so I figure a 1ohm 5W resistor should Do am I right?

Right now, I am going to say no, that doesn't sound right. What values are you using for your calculations?

Captain
01-10-2013, 07:09 PM
Umm I followed the formula in the users manual for the Nano Biscotte. (3.7v - 3.1v) / 1A then for Watts well 3.7v x 1a. Thats what I guessed.

Forgetful Jedi Knight
01-10-2013, 07:17 PM
Umm I followed the formula in the users manual for the Nano Biscotte. (3.7v - 3.1v) / 1A then for Watts well 3.7v x 1a. Thats what I guessed.

Ummm - computer says... Nah. :confused: It's more like 1 Ohm, 1 Watt resistor. Your calculation for the wattage was WAY off. ;)

Captain
01-10-2013, 07:19 PM
Can you show me how you figured it out so I can see what i did wrong in my calculations?

Captain
01-10-2013, 07:27 PM
Also i don't see any 1ohm 1w resistors on the store site. Would a 2w suffice?

Forgetful Jedi Knight
01-10-2013, 07:27 PM
Can you show me how you figured it out so I can see what i did wrong in my calculations?

From the top...

R = (3.7 - 3.1) / 1 = .6 ohm rounds up to -> 1 Ohm

P = R * I^2 = .6 * 1^2 = .6 Watt rounds up to -> 1 Watt

Even if you substituted the 1 ohm for .6 ohm in the second calculation, you would still get to 1 Watt ;)

Got it now?

Captain
01-10-2013, 07:31 PM
So I was right about it and my father not so right. I hope radio shack sells 1o 1w resistors.

Forgetful Jedi Knight
01-10-2013, 07:32 PM
Also i don't see any 1ohm 1w resistors on the store site. Would a 2w suffice?

You could try Radio Shack if there is one nearby you. Otherwise a 1 Ohm 2 Watt would work if you couldn't get the other one.

Captain
01-10-2013, 07:33 PM
Thank you for all your help. Now I can complete my order finally.:)

Forgetful Jedi Knight
01-10-2013, 07:58 PM
Thank you for all your help. Now I can complete my order finally.:)

Depending on how good your Radio Shack is, they should. Good luck with your build.