NDSi LED Moding Questions

Discussion in 'NDS - Flashcarts and Accessories' started by Dead End, Apr 11, 2010.

Apr 11, 2010

NDSi LED Moding Questions by Dead End at 11:41 PM (810 Views / 0 Likes) 3 replies

  1. Dead End
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    Member Dead End GBAtemp Fan

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    1. Are Installing Led's in a DSi the same as the DS Lite?
    2. Would i need Resistors?

    Not Relating to a DSi
    Would i need a Resistor in a Wiimote?

    Plz Answer soon
     
  2. FAST6191

    Reporter FAST6191 Techromancer

    pip
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    I do not know the specific resistances of the DSi (or DS lite for that matter) but it would largely depend on the LEDs you are using as replacements;
    resistors can serve many uses but when it comes to LEDs and simple things like this they are usually there to step down the voltage and/or limit the current flowing through that given loop and in the case of replacement with different components they are there so as to mimic the resistance of the device you are taking out.

    To this end get your multimeter out and stick it in resistance mode and then measure the DSi LED
    If polarity is not obvious use the voltmeter setting and figure that out from a powered DSi as well, most LEDs operate at similar voltages order of magnitude wise but some of the more exotic materials (colours) do change this (raising it up and above that of your bog standard LED) so make sure it is suitable.

    Also consider that many things have a safe operating range so you need not mimic the exact conditions.
     
  3. Dead End
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    Member Dead End GBAtemp Fan

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    Wow... ill be sure book mark this to for when the LED's Arive

    Ok so I would Need Resistors..

    This is the Details Straight from the Site
     
  4. FAST6191

    Reporter FAST6191 Techromancer

    pip
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    I have no DSi to pull apart so I am unable to call it but that does help a bit

    Forward Voltage (V) : 3.2 ~ 3.8 (quick aside- that is a rather low maximum voltage but a decent operating voltage and your quote does not have another value for maximum so until I know otherwise I am going to assume 3.8 is the maximum)
    This means it should glow green at around 3.2 V- possibly a bit higher than the DSi LEDs you are replacing but 3.3V is a common voltage to work at inside circuits.

    Re resistors: yes you will need for "raw" batteries/power sources but the designers of the DSi also know this so there is likely a resistor already in the circuit. You may however find this pre existing resistor to be wrong for your needs so you may have to remove or "bypass" (with surface mount tech this usually means solder over it/bridge it) it.
    As it pertains to your LEDs there are three main things you want to know (in addition to the operating voltage above)
    Max Power Dissipation : 80mw
    Max Continuous Forward Current : 30mA
    Max Peak Forward Current : 75mA
    Everything else is useful for the would be electronics engineer but for your purposes can be ignored.


    75mA is the absolute maximum- any more and it will probably burn out. You need not concern yourself with the really involved stuff like capacitor discharge pushing over that limit (what that rating is most likely to be used in) as you can assume the DSi designers took care of that.
    30mA is the maximum for the "ideal" current. Assume it is running continuously (power, charging, wifi and the like) so do not be tempted to "break" the spec.

    Power Dissipation you can ignore for the most part unless it turns out you are running at a slightly higher voltage at or around the Max Continuous Forward Current- 80mW is just below it so just make sure it is not free floating in air or it will overheat and destroy itself sooner rather than later (or just stick a resistor in there). A quick aside is that those seem to be your standard bulb LEDs while the DSi would most likely use a surface mount one, while it will not trouble the electronics side of things so much it might not look all that brilliant.
    http://www.ledshoppe.com/Photo/Product%20photo/PICT0155.JPG is what appears to be coming in your chosen LEDs while the DSi ones will look something like http://media.digikey.com/photos/Lite%20On%...TST-C150YKT.jpg

    I dare say you also want to read something like http://www.kpsec.freeuk.com/components/led.htm as it covers the general theory behind LEDs and how they play in circuits.

    You replace the LEDs where you found them unless where you found them does not meet the requirements (when replacing fans with higher end ones I will often draw from a point that is at a higher voltage or a point able to dish out higher current- it is part of the reason I mentioned that it might be higher). Naturally for something like this if you have to source power from another point then you will need to stick a transistor in there to get it to switch on and off as necessary.

    Re: Wii-motes the logic/practices used here follow for all electronics.

    I know I have just thrown lots of electronics at you but for the most part this sort of thing is as brutally simple as you probably thought it would be as you set out to do it- you locate the LED, you check to find the polarity (LEDs have a positive and a negative side remember) and you swap them over observing said polarity. The extras I mentioned are still important and should not be skipped over but take it a step at a time and you will get it done.
     

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