Help wiring up 940nm IR leds

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xSP
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Help wiring up 940nm IR leds

Post by xSP » Thu Feb 14, 2019 8:29 pm

So I am using 940nm leds(IR204-A to be specific) to make a custom Wii sensor bar. I am having troubles wiring them up and am hoping I can get some assistance.
So I know that I need a resistor with the led so that it doesn't burn out. I went here https://www.digikey.ca/en/resources/con ... s-resistor entered in my values and it told me that I need a 1ohm resistor. So I bought these https://www.arrow.com/en/products/cf14j ... lectronics to use with it. Im using a 5v 2a power supply as my power source.
This is a bad paint drawing of my wiring.
led schematic.png
led schematic.png (12.14 KiB) Viewed 4227 times
I think that my resistor is the issue, and that too much current is being put into the led killing it.
Any help is appreciated.

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tinkerBOY
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Re: Help wiring up 940nm IR leds

Post by tinkerBOY » Sat Feb 16, 2019 3:01 am

Try 1k-10k ohm resistor.
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xSP
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Re: Help wiring up 940nm IR leds

Post by xSP » Sat Feb 16, 2019 5:34 pm

tinkerBOY wrote:
Sat Feb 16, 2019 3:01 am
Try 1k-10k ohm resistor.
I tried a 14k resistor which brought the voltage down to 1v but still nothing. Can I use my phone's camera to check to see if the led is on? And is there a certain voltage that I should give the led?

McGyver
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Re: Help wiring up 940nm IR leds

Post by McGyver » Sat Feb 16, 2019 9:43 pm

According to diode IR204-A data sheet typical current should be 20mA at 1.2 Volt forward voltage. Meaning your resistor should drop the remaining 3.8 Volts from the 5 Volt power source. 3.8V at 0.02A resulting a resistor value of 190 Ohm. Or something available close to this value.
IMG_20190217_124442__01.jpg
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xSP
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Re: Help wiring up 940nm IR leds

Post by xSP » Sun Feb 17, 2019 1:28 pm

McGyver wrote:
Sat Feb 16, 2019 9:43 pm
According to diode IR204-A data sheet typical current should be 20mA at 1.2 Volt forward voltage. Meaning your resistor should drop the remaining 3.8 Volts from the 5 Volt power source. 3.8V at 0.02A resulting a resistor value of 190 Ohm. Or something available close to this value.
I tried a 170ohm resistor and it brought the voltage down the about 1.1v, but the led still didn't light up when I looked at it with my phone's camera. Is there anything else I can try?

Edit:
I just tried turning off the lights and my phone picked up the leds and a Wiimote worked with them. Thanks for the help!

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