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BenPass
11-27-2012, 10:03 PM
Hi there folks, I am new to this forum, and I am lost. Anyway, what I'm trying to find out is if you HAVE to use a 18650 cell with the Biscotte board. I know that's what is recommended, but is it necessary?

I am used to wiring up stunt builds, and tend to use two 14500 cells in my builds. Anyway, what I'm planning for my build is a RGB LED module, BuckPuck (1000mA), switch (the simpler and smaller the better), and possibly the Biscotte board. If I can use the two 14500 cells, wonderful, because I already have a battery pack/speaker combo. If I HAVE to use the 18650 cell, then I do have a battery pack, but I'll need to order a speaker, so somehow salvage the one I have on the other pack. Like I said, I'm totally lost and could really use the help.

Thanks in advance for any help.

Ben

Caine Drathul
11-27-2012, 11:04 PM
As long as it it's 3.7V the board is good to go. It cannot take 7.4V so that is out of the question. Just use a dummy cell and you can use your current setup. It just won't have very long run times compared to an 18650. Although I don't see a point of using a buckpuck. Most of us who use a N.B. wouldn't use one.

Xevious
11-27-2012, 11:58 PM
I assume you're going to use the two 14500 in parallel. Just wire everything up to the NB -- the buckpuck is superfluous.

Silver Serpent
11-28-2012, 05:32 AM
Buckpuck requires over 5v to run. The NB takes 3.4v - 5.5v. There are very few power options that let you run both of those without some fairly complicated wiring schemes.

I'd go with a resistor.

As for the batteries, I agree with Caine. Pop a li-ion and a dummy cell in your battery holder and you'll be good to go. If you're feeling adventurous, you could rewire the battery holder so that the batteries are parallel instead of in series. You could then use two li-ions for double the runtime.

Darth Obi Don
11-28-2012, 09:00 AM
Hi guys ,I' new too.
How do you rewire the battery holder for parallel operation?

Silver Serpent
11-28-2012, 09:13 AM
A normal battery pack is wired in series. The black wire connects to the first battery's negative terminal. The first battery's positive terminal connects to the second battery's negative terminal. The second batteries positive terminal connects to the red wire.


To rewire it as a parallel setup, you will need to modify the pack as follows:

Both batteries' negative terminals connect to each other and also to the black wire. Both batteries' positive terminals connect to each other and also to the red wire.

BenPass
11-28-2012, 09:48 AM
Alright thanks for the help folks! I tend to use the BuckPuck so I can use QDs on my LEDs, but if you say that such a thing isn't necessary, then that's definitely good to know. I wasn't planning to wire the batteries up in parallel, simply because I'm not sure about how to do it. I would gladly use the 18650 cell, but I'm in Canada and the main site says that they don't ship Li-Ions internationally. That, and I'm not sure if my current charger would support the 18650 cell.

bruzer79
02-01-2013, 07:24 PM
Sorry to resurrect this thread - found it via search. I'll be receiving a NB tomorrow and I want to put it in a saber that originally came with 6v (4xAAA) installed. I imagine it'll be easiest to get a 18650, but patience isn't a trait I have in abundance, so I'm trying to make it work with what I have readily available. Here's my plan:

6v (Source) - 5v (running the board at 5v is my goal) / 2A = put a .5 ohm/2watt resistor between the battery pack and the NB. Should work right? I wont fry it like that. Alternatively, I could use a buckpuck, but I dunno if I wanna go that route.

Is that right?

Silver Serpent
02-01-2013, 07:48 PM
Use 4 NiMH batteries for a 4.8v pack, or use 3 alkalines for 4.5v. If you're dead set on using the 6v pack of alkalines, then I'd get a 5v regulator from Radio Shack and wire that in instead of the resistor.

FYI, AAA alkalines don't have a great runtime with a high powered LED. If you're sticking with alkalines, switch to AA if you can.

bruzer79
02-01-2013, 10:34 PM
Honestly, the runtime isnt a huge deal for me. Its temporary until I can order\ receive a few more parts. I'll check into the regulator. Hopefully they (or my local Fry's) has something in stock. For educational purposes, why is a regulator more appropriate to use in this instance?

Edit: Just realized I already have some nimh around the house from an old RC car.. problem solved. Now I wait for the mail to run so I can get my NB. Thanks.

Jay-gon Jinn
02-01-2013, 11:10 PM
Resistors are used for limiting current, not necessarily dropping voltage. A voltage regulator is required for that.

bruzer79
02-03-2013, 02:23 PM
Can I get a match check? Im getting conflicting\confusing results.... 4x ni-mh = 4.8 v - running a blue Seoul P4 - 3.25 ( can run up to 4) foward voltage - 1000ma.

For the LED; the resistor finder on the main page says I need 1.5 ohm 5 watt resistor, while http://led.linear1.org/1led.wiz says 1.8 ohm, 1.8 amp...

I also dont understand how the difference between a 2amp power source and a 1amp LED effects the equation.

Forgetful Jedi Knight
02-03-2013, 02:48 PM
Can I get a match check? Im getting conflicting\confusing results.... 4x ni-mh = 4.8 v - running a blue Seoul P4 - 3.25 ( can run up to 4) foward voltage - 1000ma.

For the LED; the resistor finder on the main page says I need 1.5 ohm 5 watt resistor, while http://led.linear1.org/1led.wiz says 1.8 ohm, 1.8 amp...

I also dont understand how the difference between a 2amp power source and a 1amp LED effects the equation.

Ideally for what you have, you would need a 1.5 Ohm, 2W resistor.

The current (amperage) affects the second parts of the Ohm's law calculation that determines which wattage the resistor needs to be. ;)
The calculator said you needed 1.8 Ohm, 1.8 W but since 1.8W resistors are not commonly made (or available) you would round up tot he next size (2W).

In my calculation, since I do the math and don't rely on a resistor calculator) I used the Vf value of 3.3V for a blue LED, and then your battery 4.8V and 1000 mAh (or 1A) for the current). The calculation formulas are in the NB manual. ;)

spits79
02-22-2013, 06:38 PM
Hello,

I'm completely new to this and have no idea about electronics, I noticed in the bruzer post he said he has a Blue Seoul P4 which he's running at 3.25v however the shop site list this led as max 4.0v. I don't understand how you can set a LED to run at a specific lower voltage and what would be the downside with doing that?

I ask as I was thinking of getting the NB to run a Green Seoul P4 (one of the led+headsink modules) but I was thinking of putting in a single single Li-Ion 18650 however if the calculations in the manual are correct obviously this wouldn't work since the led is 4.1v (max) and the cell is 3.7v.

Btw I was so green at this I had no idea where bruzer79 had pulled the 4.8v figure from since the store doesn't list the voltage of the ni-mh batteries. It wasn't until I was looking series and parallel wiring, quick lookup of AA batteries on wiki and it suddenly triggered :)

Forgetful Jedi Knight
02-22-2013, 07:30 PM
Hello,

I'm completely new to this and have no idea about electronics, I noticed in the bruzer post he said he has a Blue Seoul P4 which he's running at 3.25v however the shop site list this led as max 4.0v. I don't understand how you can set a LED to run at a specific lower voltage and what would be the downside with doing that?

I ask as I was thinking of getting the NB to run a Green Seoul P4 (one of the led+headsink modules) but I was thinking of putting in a single single Li-Ion 18650 however if the calculations in the manual are correct obviously this wouldn't work since the led is 4.1v (max) and the cell is 3.7v.



All LED's have voltages that run within a certain RANGE. We use the average value of a specific LED color as a basis, since it will still work (maybe not at peak performance, but it will still work). In your case, a green P4 average would be around 3.4 Vf which would be UNDER the 3.7 battery voltage. If you use a 1 ohm, 1 watt resistor, your green P4 should work just fine. ;)

spits79
02-22-2013, 08:07 PM
Cool that's good to know but just for my interest is there like a rule of thumb here for calculation like this. For example following on the same idea if I wanted say an illuminated switch, the NB can give out 3.3v which is the max for the switches (3.3v 20mA) which again according to the calc in the documentation is (3.3-3.3)/0.02 technically is 0. Now I assume the same sort of situation applies where the average draw would be lower than the max but I don't know what this is.

Forgetful Jedi Knight
02-22-2013, 08:47 PM
Cool that's good to know but just for my interest is there like a rule of thumb here for calculation like this. For example following on the same idea if I wanted say an illuminated switch, the NB can give out 3.3v which is the max for the switches (3.3v 20mA) which again according to the calc in the documentation is (3.3-3.3)/0.02 technically is 0. Now I assume the same sort of situation applies where the average draw would be lower than the max but I don't know what this is.

Simply put... it depends. It depends on the color of the illuminated switch. If it's blue or green, then you're basically safe, though a tiny resistor (1 ohm 1/4 W) is generally recommended for a a switch like that. If it's red or yellow, then you'll need a "bigger" resistor.

The 3.3V pad was designed with illuminated switches in mind, the switch LED's take 20 mAh, and the pad dishes out 20 mAh. ;)

mistersamsa
02-22-2013, 09:23 PM
Howdy all... way new to this. Running my Nano to the LED using a 1000ma buck puck. As soon as i plug in the batteries (running the 4 X AAA w/ the built in speaker) the LED comes on (solid, without the flicker). Once I hit the button (momentary) the sound and flicker comes on... what am I doing wrong?

So confused :(

spits79
02-23-2013, 01:38 AM
Actually this brings up another point do you actually need a buckpuck with the NB, I've read some posts they say yes and other that say no. I would have thought you would, since I don't think there is no current regulation withe the NB? But I digress, following on with my questions around resistance calculations...

So with say with a green led switch the output of the NB is exactly the max of the switch diode so what is the purpose of the tiny resistance in this case?

With say a red led switch if you, wanted it as bright as possible, then the maths say it would require a resister greater than 80ohm 0.035W. So a quick look on the store shows a 82ohm 1/4W resister which would fit the bill (Is the important thing to get the amp down, but the wattage just needs to be close, is that right?)

Forgetful Jedi Knight
02-23-2013, 05:49 AM
Actually this brings up another point do you actually need a buckpuck with the NB, I've read some posts they say yes and other that say no. I would have thought you would, since I don't think there is no current regulation withe the NB? But I digress, following on with my questions around resistance calculations...

So with say with a green led switch the output of the NB is exactly the max of the switch diode so what is the purpose of the tiny resistance in this case?

With say a red led switch if you, wanted it as bright as possible, then the maths say it would require a resister greater than 80ohm 0.035W. So a quick look on the store shows a 82ohm 1/4W resister which would fit the bill (Is the important thing to get the amp down, but the wattage just needs to be close, is that right?)

To answer your questions:

1. No a buck puck is NOT necessary.

2. Think of it as a tiny surge protector. It may come as a surprise to you, but newbies do have a tendency to make a mistake here and there and either fry or blow something up. I'm just trying to give your wallet a fair chance, since this is an expensive hobby. :D

3. Yes. Resistors only come in certain sizes, so you will likely have to round up (or down) to get the value closest to your calculations. ;)

Forgetful Jedi Knight
02-23-2013, 05:52 AM
Howdy all... way new to this. Running my Nano to the LED using a 1000ma buck puck. As soon as i plug in the batteries (running the 4 X AAA w/ the built in speaker) the LED comes on (solid, without the flicker). Once I hit the button (momentary) the sound and flicker comes on... what am I doing wrong?

So confused :(

It sounds like you have a bridge somewhere, either at the solder pads, or on the LED itself. Make sure you don't have any solder touching two pads simultaneously.

mistersamsa
02-24-2013, 12:26 AM
It sounds like you have a bridge somewhere, either at the solder pads, or on the LED itself. Make sure you don't have any solder touching two pads simultaneously.

Dang... I haven't started soldering yet, and I bought all my internals pre-wired. Also, just went over all my connections and they look solid. Can't think of where I could have crossed a wire somewhere.

This sucks :( my saber is soooooo almost done.

Forgetful Jedi Knight
02-24-2013, 10:52 AM
Dang... I haven't started soldering yet, and I bought all my internals pre-wired. Also, just went over all my connections and they look solid. Can't think of where I could have crossed a wire somewhere.

This sucks :( my saber is soooooo almost done.

Relax. Shoot Tim a PM, he should be back later this week IIRC, tell him your issue, and I'm sure he'll help you get it resolved.

spits79
02-25-2013, 01:16 PM
To answer your questions:

1. No a buck puck is NOT necessary.

2. Think of it as a tiny surge protector. It may come as a surprise to you, but newbies do have a tendency to make a mistake here and there and either fry or blow something up. I'm just trying to give your wallet a fair chance, since this is an expensive hobby. :D

3. Yes. Resistors only come in certain sizes, so you will likely have to round up (or down) to get the value closest to your calculations. ;)

How far can you round before you start getting into problems.... or is this like one of those "How long is a piece of string" questions.
I ask as I am having a hard time locating small resistors (like a 1Ohm 1W) and I know this site sell 1Ohm 2W resistors... if I understand the principals of electronics (and I probably don't) a higher Watt resistor is just a greater drain on the batteries, is that right?

Silver Serpent
02-25-2013, 02:10 PM
Higher wattage resistors can handle more power flowing through them before they go "pop". Wattage doesn't affect battery drain, brightness, current, or any other electrical factor. You can use any wattage resistor you like, so long as it meets the minimum required for your application.

Don't go overboard and use a 10w resistor where a 2w will work. Larger wattage resistors are physically larger, and will take up a ton more room in your hilt. The saber will work the same way in either case, but space gets tight very quickly inside your saber.