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Using Arduino with Fiber Optic Light Source
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Please be positive and constructive with your questions and comments.

Using Arduino with Fiber Optic Light Source

by exaltron on Fri Nov 26, 2021 10:33 pm

Hi, I am a relative noob but I've completed a few arduino projects involving through-hole, RGB and neopixel LEDs. I'm having some trouble getting the wiring right for the Fiber Optic Light Source I purchased here. On the product page it's recommended to power the light source with a power adapter so I'm using this one.
The only way I can get the light source LED to light up is to connect the red wire to the Vin and the black wire to the GND. Any other typical LED wiring doesn't work, even with something basic like the Blink code. Attached is a snapshot of my breadboard with the positive connected to pin 13. Do you have any suggestions for wiring diagrams I could reference? I ultimately want to connect five of the light sources to different pins and control them using the maxuino device in Ableton (see attached screenshot). Thanks in advance for any suggestions!

maxuino screenshot.png
maxuino screenshot.png (69.85 KiB) Viewed 419 times


arduino snap.jpg
arduino snap.jpg (899.21 KiB) Viewed 419 times

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Re: Using Arduino with Fiber Optic Light Source

by adafruit_support_bill on Sat Nov 27, 2021 7:09 am

Arduino pins can only provide a few mA of current. That is sufficient to light up a small LEDs. But more powerful LEDs like the fiber optic light source require more current.

If you want to control that current with an Arduino pin, you need to use something like a transistor to switch that current. You can use one of the circuits shown on this page: https://learn.adafruit.com/rgb-led-strips/usage

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Re: Using Arduino with Fiber Optic Light Source

by exaltron on Sat Nov 27, 2021 10:22 pm

OK awesome that makes sense! I will grab some transistors and give that a shot. Thanks for the quick response!

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Re: Using Arduino with Fiber Optic Light Source

by rpiloverbd on Fri Dec 03, 2021 3:52 pm

The product description says this fiber optic source needs 9-12V 100mA. Arduino UNO I/O pins only give 20mA. I think you'd better use an IRF540n MOSFET.

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Re: Using Arduino with Fiber Optic Light Source

by exaltron on Tue Dec 07, 2021 10:34 pm

Ok I read the guide to using transistors but I think I misunderstood. I ordered TO-220 transistors which are P-channel and I can't seem to get them to work in any configuration. Maybe it would make more sense to just get the N-channel transistors recommended on that page? it seems like they could handle the amperage but I don't understand this part:

For basic, low-cost usage we suggest using N-channel MOSFETs such as the IRLB8721 - they are very popular and inexpensive and work with 3.3V or 5V logic. If you can't get those, TIP120 are also good but there is more voltage loss in a transistor than in a MOSFET which is why we suggest those first (less heat loss, more light!)


3.3V or 5V Logic would include using the PWM outputs of the arduino is that correct?

It seems like the simplest way forward would be to pick up the IRLB8721 transistors and wire up as shown in the diagram?

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Re: Using Arduino with Fiber Optic Light Source

by adafruit_support_bill on Wed Dec 08, 2021 7:19 am

The logic levels for the Aruduino UNO are 5v, so it will work well with either the TIP120 or the IRLB8721. The IRLB8721 is a bit of overkill for this application, but they are simple to work with and don't require any additional resistors or other components.

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Please be positive and constructive with your questions and comments.