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I'm new to the RPi. I'm looking to put a light inside my RPi case for a glow effect. But since I'm not an electronics guy, I have no idea what kind of an LED I can use and where to put it inside the RPi. I believe it would be put somewhere on the GPIO port and since that's a little away from the center, the LED will have to be powerful enough to shine through and light up the whole of the inside. :idea:

Also - I don't want to permanently use up the GPIO port for the in-case lighting. I only need to draw power from it, so I can connect another add-on later on when I want to.

Any recommendations on how I can go about doing this? What kind of LED light I should ask for and where do I fix it?

I looked at the PiGlow. This is interesting, even though it would be a bit of an overkill for whatever use I have in mind. About $15 is a bit much, so I was wondering if there are any single-purpose, lower cost alternatives. I don't even know what to look for.

PiGlow

I also found this starter kit on eBay (http://www.ebay.com/itm/121251111290) which seems to have the LEDs, switches, wires and also a breadboard for some slightly more advanced stuff.

Kit

This is the next step for me, but I just want to start with the basic light only.

There's also another listing for only LEDs (http://www.ebay.com/itm/281231405437) - about 100 of them, but that's not the point - which, they say, can be used with the RPi.

LEDs

If I get a couple of these, will I be able to get them to work directly with the RPi, or will I need to use some breadboard type stuff? Since all I want is an in-case light when the RPi is turned on and no user control or anything, I wonder if I can use it directly.

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In your GPIO connector you have lots of ports to use. You have your GPIO ports that you manager from the PI, and you want to keep for your future projects. But you also have a simple +5V output and a ground (GND). This two little guys have a current going through them all the time the PI is on so, connecting a led here will light it up as long as your pi is running.

To connect a LED you need to add a resistor in series to it. The schema will be as simple as :

+5V----resistor----LED----GND

Please notice that the LEDs have polarity and they will only work when connected in the correct direction (connecting them backwards WONT damage anything so, no worries)

About the resistor:

    A standard red LED usually has a voltage drop of around 1.7v,
    so the value of the resistor can be chosen to pass 20mA at (voltage - 1.7).
    Assuming an input of 5v, this means a resistor that will pass 20mA at 3.3v,
    which (using Ohm's Law) gives us an absolute minimum resistance of 165 ohms.

About the LED themselves.

    You have different LEDs out there, the standard ones will follow what I wrote.
    More powerful LEDs will draw more current, leading to smaller resistors needed.
    3 legged LEDs are more complicated and not good for this starting point.

Here is a tutorial that uses the 3.3V pins instead of the 5V. I chose this one so you can see another example of how the resistance is calculated.

Have fun !

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To get lighting inside your case, you're going to need an LED, a resistor and some wires to connect it together.

Your main restricting factor will be the amount of space left inside the case once you've put the Pi in. Doing any sort of breadboarding is not going to be an option as the board itself takes up a great deal of room - even the smallest size breadboard is going to be too thick, plus the wires will project out of your GPIO pins too high. About the only option you've got for doing it yourself would be to solder wires directly onto the GPIO pins, add an inline resistor and then the LED.

If the PiGlow is too expensive for you, can I recommend the LEDBorg? http://www.piborg.com/ledborg

  • Could you point me to a place that explains this in more detail? I have absolutely no experience with this and I don't even know what to look for. The LEDBorg looks nice - I'll consider it at a later stage! – aalaap Feb 18 '14 at 7:41
  • Take a look at my circuit diagram here: fritzing.org/projects/raspberry-pi-simple-switched-led – recantha Feb 18 '14 at 10:55
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While it's always worthwhile learning to wire things up yourself, it's nice to have an inexpensive packaged product sometimes. You might be interested in the $7 Pimoroni Blinkt from the same company. It provides 7 individually-addressable RGB LEDs.

PiGlow is available for roughly $10.50 now.

  • I know I said that the PiGlow was beyond my budget, but this whole exercise has mainly been about learning and experimenting, so I'd still be interested in doing things myself. Of course, it's been years since I even took that thing back out of the box... – aalaap Jan 19 '18 at 6:42

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