LED device Help please !

[Andreas-T1]

Hello i require some advice/help please.
I'm making a cosplay item that requires 7 LED's to run of a 9v battery but the enclosure will be permanently closed so i was going to use a 9v rechargeable battery with a charging port.
Now my problem is when it comes to wiring it i have a 9v battery going to a regulator and charge port then before the array of LED's i have a on/off locking switch and 33Ohm resistor but I'm just wondering what would be the best way to wire this up?
Any help would be really appreciated.

I'm pretty poo with electronics but i usually find a guide and do it but this time I'm having a very hard time finding any info on how to do this one lol.

Thank you kindly.

 

[Martaine2005]

Hi Andreas,
What leds are they?
330Ω would be reasonable for a single led from 9 volt.
The best way is probably series strings of 3 and 4 leds.
But the leds specifications would confirm the best resistors.

Martin

 

[Andreas-T1]

Thank you for the reply.
They are these ones from Ebay

http://www.ebay.co.uk/itm/291543146611?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

and one single
RED
Vf = 2.0v
If=20mA
Casing = Diffused

 

[Martaine2005]

Hi Andreas,
wiring in the 3 and 4 series configuration would appear to be most efficient. About 40ma.
But using 8 leds would mean the same resistors and still about 40ma. You could just leave the 8th led connected inside the box and not visible.
The calculator says 56Ω, but below 100Ω is not a good idea really.
Try several sizes between 100Ω and 220Ω 1/4W resisitors to see the brightness you prefer.

Martin

 

[Andreas-T1]

Thank you.
Ill go for 150Ohm then as i don't want them super insane bright !
I need all 8 showing 7 for Dragonballs and the red single one is in the centre of the display.
With wiring the resistors do i put one before every Led then or just use the one after the switch ? also any ideas maybe a quick diagram on how to wire it all together please ?

Your a star and thanks again bud !

 

[Martaine2005]

You'll only need one resistor per string. The switch would normally go after the battery to turn the whole circuit off.

Martin

 

[Andreas-T1]

Absolutely awesome man ! your a saint amoungst men !
So the regulator and charge port would be ok before the switch unit so it can be charged when its switched of then ?

 

[Martaine2005]

Yes, keeping the charging circuit separate.

Glad you only needed 7 leds but 8 works better!!

Martin

 

[Andreas-T1]

Haha then that's brilliant as its all equal !
I'm now wrecking my head trying to work out how to wire in the regulator, charge port and switch circuit now lol !

3 prongs on the regulator ones positive in/ negative/ positive out
Battery positive goes to the 'in prong'.
Then the negative goes to the battery negative and the charge port negative.
Positive out prong goes to switch and charge port.
Does that sound right or have i got it wrong ?

Thanks again man, your brill !

 

[Martaine2005]

Battery positive goes to the 'in prong'.

Erm, can you give the FULL details of the regulator, battery and charger?
And a drawing of how you intend to connect it all?
Normally one would buy a charger for the required battery.
Making one can get very complicated and if not done correctly, potentially very dangerous too!.

Martin

 

[Andreas-T1]

You do know im British like you don't you, were a very dangerous kind of people !
its an L78M05CV - Ic V Reg +5.0V

Got the idea from here http://www.instructables.com/id/Simple-9v-usb-charger-in-an-Altoids-tin/
Its going to be a sealed unit hence the charge port for the 9V rechargeable battery inside it.
Charger is a simple USB to 5v DC barrel jack.
Barrel jack surface mounted charging port.
As i described would be what i thought was correct wiring wise, dont know how to do a drawing of one it tbh :s

 

[Martaine2005]

Lol yeah, that's why I need to double check everything you say.!!!!

Now that instructable is using 9v battery to charge another device @ 5v.
So that is not what you need at all.
Buy the 9v battery with the proper charger, then you can wire it all up without issues.

Martin

 

[Andreas-T1]

Ah poo ! so use a battery pack then ?
Ive got like really limited room in this device so thought a 9v would be perfect and give me enoguh room for the wires and regulator tbh.

 

[Martaine2005]

Something simple like this where the battery can stay inside the box.

 

[Andreas-T1]

Wait you mean just buy a power supply to directly recharge it through the socket on the device with the rechargeable inside ?

 

[Andreas-T1]

ok i see but i dont really know what im looking for with those kinds of batteries.

 

[Martaine2005]

The original battery you was talking about is a PP3 battery.
To charge that, you need a charger! Any charger that has a PP3 connector will do. But you'll have to add wiring and a barrel plug.
The charger I showed was just an example of a remote charger.
Now having read and understand your requirements more, an RC transmitter battery and charger would be much better. Not only last 100 times longer but remote charging too.

Martin

 

[Andreas-T1]

OH haha ! ok then man that's in a language even i can understand !
I dont mind it not lasting for hours an hours, its simply to power a prop that's not meant for long stints of being on tbh just quick lights on 'look' woo some people then lights off until someone wants to see it again lol !
you haver been a huge help and i dont know why i had to try and make it so complicated for myself...typical Brit ey...
Thanks again, ill upload some pics when its all done and you can make sure its all gravy
thanks again dude you are a good person

 

[Martaine2005]

From a fellow Brit,
You're very welcome. And I look forward to seeing the pictures.
Good luck

Martin

 

[Andreas-T1]

I cant wait to have it built if i'm honest with you lol
Thank you very much.