Wiring LED TO helmet
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Walter Spase
Well-Known Member
tick said:
Lol, I am going to encourage you to take note of the date of the posting for the question that you are answering.
You answered a question from 10 months ago, I hope he figured it out by now.
Thats been addressed....
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Yodajammies
Well-Known Member
Spase, why is your resistor AFTER the LED element?
You're asking for burnt out leds man. You need to drop the voltage before it hits the leds.
You're asking for burnt out leds man. You need to drop the voltage before it hits the leds.
Walter Spase
Well-Known Member
Yodajammies said:
Thanks for the Valid question... but location in this circuit is irrelevant.
The resistor location technically doesn't matter at all in this type of circuit, for the diagram I have drawn. The resistor does not NEED to come before the LED in a circuit path from positive to negative. The current is limited regardless of resistor location. However in this diagram it does come before the LEDs , in the circuit path from positive to negative. Moving the location of the resistor to anywhere in this circuit will result in the same outcome.
Here is another version of the same schematic, showing the battery terminals. (DO NOT SOLDIER DIRECTLY TO THE TERMINALS)
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Yodajammies
Well-Known Member
...
wow, was I drunk when I wrote that? essh.
Yeah, you're right.
wow, was I drunk when I wrote that? essh.
Yeah, you're right.
Twitchfmx8811
Well-Known Member
Ok I have a question. I bought some LEDs, battery holder, LED holders, and a switch. The LEDs are 3.3v and 7000mcd. I am running them off of 4 AAA batterys. My question is do I need a resistor? They guy at radio shack said no and my girlfriends dad said he wouldnt think so. I just need to know before I wire them in.
Ral Partha
Sr Member
LEDs have very small resistance so putting them in a circuit without any resistors will burn them out the instant you flick the switch.
Gokussj5okazu
Well-Known Member
Here ya go, Twitch. This will work for ya.
[attachment=4740:led1.PNG]
[attachment=4740:led1.PNG]
Twitchfmx8811
Well-Known Member
Ok well I was going to wire them in either like Spase's last diagram or like this
Also what Ohm resistor should i get?
Also what Ohm resistor should i get?
Walter Spase
Well-Known Member
@TwitchFMX8811
That circuit diagram you have show should technically not work at all with only 4AA batteries in series (as most battery holders are). You are only supplying 6 Volts. The way you have it wired is (two LEDs wired in series) wired in parallel with (two LEDs wired in series). Therefore at 3.3 volts + 3.3 Volts... you would need 6.6 volts nominally to power the two LEDs in series. You only provide 6 Volts nominally, with 4 AAs in series.
You can either up the Voltage to 9Volts, in which case you'd want one 30 Ohm resistor, or it just wont work (not all 4 LEDs).
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@Gokussj5okazu
How would this circuit work either... if the LEDs are 3.3 Volt, most likely 20mA desired LEDs, then you'd need at least 34+ Ohm resistor to keep the Amperage down to at or below 20 mA. Resistor of a lower value will cause one LED to burn out, which will cause a chain reaction and all of the LEDs will eventually "cook". That is all assuming you have 20mA rated resistors. If you had 45mA rated LED, then what you have there should work.
That circuit diagram you have show should technically not work at all with only 4AA batteries in series (as most battery holders are). You are only supplying 6 Volts. The way you have it wired is (two LEDs wired in series) wired in parallel with (two LEDs wired in series). Therefore at 3.3 volts + 3.3 Volts... you would need 6.6 volts nominally to power the two LEDs in series. You only provide 6 Volts nominally, with 4 AAs in series.
You can either up the Voltage to 9Volts, in which case you'd want one 30 Ohm resistor, or it just wont work (not all 4 LEDs).
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@Gokussj5okazu
How would this circuit work either... if the LEDs are 3.3 Volt, most likely 20mA desired LEDs, then you'd need at least 34+ Ohm resistor to keep the Amperage down to at or below 20 mA. Resistor of a lower value will cause one LED to burn out, which will cause a chain reaction and all of the LEDs will eventually "cook". That is all assuming you have 20mA rated resistors. If you had 45mA rated LED, then what you have there should work.
Twitchfmx8811
Well-Known Member
ok I think I got this figured out. If I use 2 9v batteries and use spases diagram this should work.
2x - 9v batteries
4x - LEDs 3.3v 25mA
1x - 220 ohm resistor
I used this site to calculate this. Correct me if im wrong.
Just one question. Is there a certain way you need to face the resistors? If so which way.
2x - 9v batteries
4x - LEDs 3.3v 25mA
1x - 220 ohm resistor
I used this site to calculate this. Correct me if im wrong.
Just one question. Is there a certain way you need to face the resistors? If so which way.
Walter Spase
Well-Known Member
TwitchFMX8811 said:
Doesn't matter which way, resisters are non directional.
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Macattack64
Well-Known Member
I was looking at that site too... and when I punched yours in there... Theoretically it should work as bright as its supposed to... :\... but it doesn't...
Also is there a way to put in 3 different colors of lights instead of 1 white and have it wired some how to blink to beats of like music...
Also is there a way to put in 3 different colors of lights instead of 1 white and have it wired some how to blink to beats of like music...
HaloZombie
New Member
I know you got help but here's a cheap and easy one. Go buy four little keychain flashlights and bondo them in. Make the buttons on the back stand out so you can turn it on and off.
Macattack64
Well-Known Member
You'll have to make sure they are the same color and are the ones that you can click and will stay on... most you have to hold down urself...
Walter Spase
Well-Known Member
Macattack64 said:
Who are you referring to?...
If you are talking to me.... and have you wired it up? What are your component specs? Most I can think is you have a dead battery, miss matched components, or the wrong Resistor value.
And yes, blinking LEDs to music is possible, but a fair bit more complicated.
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Silverzippo93
Well-Known Member
lolollloolololotick said:
I got it almost a year ago.
That was a good laugh.
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TheSpartanMjolnir
Member
Ronin said:Here is the wiring harness I made for my helmet. All of this can be purchased at Radio Shack. Except the the wire I used. Everything worked good last Saturday at AdventureCon. The battery on the fans did gave out on me after about 4 hours.
.
That's pretty good. my only complaint is that the switch is all the way in the back where your back side of your head is. usaully you see Adam and other turn on the switch by the side
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