T-800 Skull

ya that would be cool , i have not made a tut before i can post it on my site. i am pretty busy in school right now. All my lights were back at home but i can do one with some pretty basic lights.

That is is 2nd fav part of model building the photographing of them giving that final presentation 1st i painting and weathering.

no problem!

but hey, once you have the pics, you wouldn't mind sharing them eh? please do!

good luck with it! let me know if you have any problems..

oh and btw: since you are in film school, cant you make a quick tut. about taking decent pics from our models? just my thanks!

Thanks for the posts its helping me learn more about electronics. I am in film school and i like to photograrph models and make them look as if they were from the movies but alot of mine needed some lights in the models for the illusion to work.

no prob. last note though: if you were to attach a resistor, the leds would be permanent :)

Hope you or maybe some1 else who wants to light up their models but dont have any electricity experience (like me..) found the post usefull..

Most of the time I dont use LEDs.  And if I do, they are pre-wired in a circuit. I just quickly threw in a couple on this one for fun.  They arent intended for prolonged use.  Usually just a minute or two.  But if they ever fail, they can easily be swithed out for something more permanent. 

And thanks for the google tip.  I may need that in the future.

viper_mp wrote:

Sometimes thats all you need to do.  It really depends on if you are running it for long or short time periods.  I set up mine for short, so its just two 12v LEDS hooked to a single 9v. Gives it a little more run time.

im afraid i dont agree.. the problem is not the voltage, but the Amps.

a normal led on full intensity pulls something like 20 Amperes, so 2 leds: 40 Amps. now check your battery to see howmuch amps its delivering (depends on battery) obviously, it will give more than 40 amps, the voltage is not that important. You need to take away the rest of the amps so the leds will only get 20 amp, otherwise they will burn out way too soon... (the wattage will be too high in leds..)

you can compare it with a river:

the width of the river: VOLTAGE (U)

the quantity of water streaming through the river: AMPERE (I)

controlling the quantity of water (like a dam): RESISTANCE (R)

energy consumed by components: WATTS.

With a lot of water in a small river, the water will stream fast and hard (low voltage lots of amps, meaning preasure, stuff gets really hot..)

With a very wide river, but only a glass of water, no preasure at all.

What you want to do, is create a river wide enough to let enough water through to power your components, and than create a dam, so you control how much water is entering. Obviously the width of the river controls the amount of water that CAN be put through, so the resistance depends on this.The minimum width of your river depends on the led, normally they require 2-3 Volts.

 

how? again: U=IxR

it will give you 100.000 hours of life for a led if you screw down the amps, and since resistors dont cost anything really, imho its really worth wile protecting the leds.

so in your case you have 2 leds:

2x2Volts = 4 volts (so a 5 volt battery will do) 5 volt - 4 volts = 1 volt too many..

so u=ixr => 1=20xR ==> R=1/20 ==> 50 Ohm. (next high value in E12 series will do nicely)

in your case you have 9 volts:

2 leds = 4 volts ==> 9 volt - 4 volts = 5 volts too many:

u=ixr ==> 5=20xR ==> R = 5/20 = 250 Ohm

next resistor from E12 series in your case: 270 Ohms.

Hope its a bit more clear now, and you see why you really DO need to hook up resistors to a led, nomatter the voltage.

 

ps: if you dont trust my or your own calculations, or if you are just too lazy for it, google for: resistor calculator, lots of them! just give the power supply, nr of leds et voila, you have your resistor... :)

gr. S.

Sometimes thats all you need to do.  It really depends on if you are running it for long or short time periods.  I set up mine for short, so its just two 12v LEDS hooked to a single 9v. Gives it a little more run time. 

The Mage wrote:

So if i wanted to put leds in my model all i need is to hook it up to a battery?

nope, you gotta hook up some resistors as well, otherwise your leds would have a short life indeed..

losta electronics tuts, but it comes down to: U=IxR...

Cool i like it when people add simple modifications to make something cool .

So if i wanted to put leds in my model all i need is to hook it up to a battery? I want to put some lights in some of my models but i always heard its hard to do it.

Any other shots of it , in better lights ?

Thanks for the comments guys.  

The eyes do not fade.  They are real simple, two red LEDs wired to a 9v battery.  No circuits at all.  The eyes themselves are clear plastic cut from a blister package.  the backside as sanded in a circular pattern, which acts as the diffuser.  I glued square pieces on balsa wood behind the eyes, with holes drilled for the LEDs.  The inside of the eye and the wood were painted in flat black, and the eyes were painted with tamiya clear red mixed 5-1 with clear smoke.  The red LED is centered in the eye, so the black around it works with the diffuser to give the overall eye a red to black fade.  and when the eyes are off, they are solid dark red/black.

What did you use for the difusers?

That looks great, I had the all vynil verson of this. I got pissed at it, threw it on the floor, after picking it up I havent touched it since.

i really like the eyes, do they fade in/out?

that looks great  good job on the shading

 

 

 

k