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i was wondering: does all white led have the same voltage and mA? because i'm making a backlight mod for a Dreamcast's VMU , i've pulled out from a broken 2" lcd his backlight stuff (leds and plastic sheets wich diffuse led's light homogeneously). i've cutted out all the unnecessary plastic so now it fits perfectly in the back of vmu's lcd. all i need now is to know how to wire these 4 leds. Obviously they're white, but much smaller than common leds, do they work at 3V anyway?
Hey man, I've been on a Dreamcast binge lately, and just last night, while playing EGG I was wondering if it would be possible to add a light for the VMU! although I was thinking of just adding an LED to the controller itself, right above the VMU's view port, but if I understand You, you want to ad one internally, right? That would be pretty slick, but don't You mean 6V since a VMU runs off of two 3-volt button cells?
Either way, it would be pretty cool.
i've already modded a controller placing a led in the middle to light up the vmu years ago. the final result is nice, but a led in front have to be bright enough to reflect it's light on vmu's screen, it's an annoying spotlight from the bottom when you're playing in the dark. Things gets worse if you have a crt, plasma or a lcd with shiny glass on it because you can see that damn spotlight reflected on the screen! :mad:Quote:
Originally Posted by fatboy
http://img297.imageshack.us/img297/2489/joyi.jpg (notice the analog stick mod :p )
a proper backlight would be much better, is less bright and less annoying, it shouldn't reflect on tv anymore too, because the light source would be in a different angle :p
i was asking about leds itself, vmu takes 6volts from batteries, but from the link port it inputs around 3,30V on pin1 and outputs around 3.50V on pin 14Quote:
but don't You mean 6V since a VMU runs off of two 3-volt button cells?
http://www.maushammer.com/vmu2vmu.html
i was wondering if i can wire these backlight white leds straight to pin 1 and ground just like my previous mod without risk or if this would fry them
Ah, I think I see what you're going for: Although the led's will be inside the VMU, You want them to be powered off of the console, right?
I like the led mod on the controller, BTW
exciting news:
the backlight trick worked better than expected, the effect is amazing!!
http://img707.imageshack.us/img707/7...cn0680z.th.jpg
sadly the only way to light 'em up is from the original hardware (the unmounted mp4 on top), can't understand why, i've tried by a multimeter, it says around 3,5V output from the original source, just perfect for a vmu, i could solder them straight to pin 1 and ground, but if i do that, nothing happens :( (i tried to reverse wires, to check if i had reversed polarity, but nothing). i'll test it soon disassembling a controller, plug the vmu in, turn dc on and see if text and pics looks good (sadly his buttons batteries are dead and i don't have others for test right now)
EDIT: i was checking with the multimeter again, it is 3,5V while it's not lighted up, when it is lighed up it says around 40V!?! serously!? 4 white leds in series? o.O
yay! it's perfect! :p
i tought the lcd would appeared grayish and washed out with backlight, but it is a nice solid blue :cool:
http://img413.imageshack.us/img413/8593/sa2o.jpghttp://img444.imageshack.us/img444/7677/sa2snc.jpg
This is AWESOME :D
Thanks! :D
now i've figured it out, somehow, if i check voltage from source without leds, it says an insane rating (40-50V) if i check while it is supplyng leds it says 8,65V between the first led's anode and last one cathode (they're 3 in series), and 2,91V on each led, this make some sense XD
but vmu have only 3,3V on pin1, and 3,5V on pin 14, i should cut original traces and wire leds in parallel. But after that, shoud i add a resistor?
I think with LEDs its always a good idea to add a resistor, but saying that if its not above 3v or so I wouldn't bother.
Very impressive though, very uniform and sexy lookin! makes you wonder why SEGA didn't do it in the first place.
You should use some resistor, to limit current draw and brightness... less brightness- longer battery life. R=U/I, LED is say 20mA, supply is 5V, 5V / 0.02A = 250ohm
thanks! and you're right, why they didn't? it looks great!Quote:
Very impressive though, very uniform and sexy lookin! makes you wonder why SEGA didn't do it in the first place.
thanks for the info, but why 5V? pin 14 is 3,5V, so the resistor should be 175ohm right?Quote:
You should use some resistor, to limit current draw and brightness... less brightness- longer battery life. R=U/I, LED is say 20mA, supply is 5V, 5V / 0.02A = 250ohm
i'm interested on this pin because is an output, not input (i've seen it on this page http://www.maushammer.com/vmu2vmu.html ), it should be to supply power to the other VMU (or MU) when plugged together, this make me think the backlight would show up anyway if the vmu is plugged to the controller or if powered by batteries
I just gave random figures. Also, I do not know how big is the current draw of your backlight setup... typical single briiight white LED is 20mA.
This is so damned cool! I love hardware mod's that actually serve a purpose!
it's finished! :p
http://img146.imageshack.us/img146/1043/leds.th.jpghttp://img687.imageshack.us/img687/1...cn0715s.th.jpghttp://img515.imageshack.us/img515/3459/vmulight.th.jpg
i'm really satisfied of the final result, it gives even a much better feeling with the controller, it looks somewhat more professional, i recommend this mod!
apparently i've burned the led in the middle, it won't light up, but maybe i've not soldered it well. i should open it again to check but is a pain, i had only electric tape to riassemble plastic sheets and leds togheter. make the result something decent needs precision and patience, and it's damn boring. luckily, the dead led is not so noticeable, the screen lights up well anyway :)
looks good, but you can kinda tell its burned out at the bottom.