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Troubleshooting usb powerbank 3 IR LED setup Answered

I am an amateur with setting up circuits, but I am really interested and understand most electronics, I am just confused with the issue I am having.

I am building a wireless google cardboard so that I can play PC games on my phone through the VR headset rather than crappy app games.
Basically a wireless Oculus Rift, however I know it wont be anywhere near as good it's just a fun project.
I have Infrared LEDs which I will use with freetrack and my modified webcam without IR filter to do my head tracking.

I am trying to power 3x Infrared LEDs from a usb powerpack. Here is the one I am using http://www.ebay.com.au/itm/221468778309?var=520334132263&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

The reason for using this as a power source is I can easily attach it to the headstraps on the google cardboard, it is just about the smallest power setup I can think of (better than using 3x AA batteries), it was cheap, and it outputs 5v which is perfect for powering 3x IR LEDs with a forward voltage of 1.6v and 60mA current.

When I use this powerbank to power a single LED without a resistor and I look at it through my webcam, even with all the lights off and the webcam 5mm away from the LED you can barely see it light up.
I tried the led on another powerbank I have here which is 10,000mAh so it is massive, and it was much brighter on the webcam. I then used my samsung TV remote and pressed a button while aiming at the webcam and it was EXTREMELY bright. Basically I want the LED to be as bright as my remote, or as much as the LED is capable of.

Why would the powerbank show the LED so dull? I have confirmed it is outputting 5v, but when I try test the current with a 'usb charger doctor' between the charger and usb cable, or a multimeter between the wire and the LED it shows zero current.

I should be able to just connect all LED in series with a small resistor and it should just work at full brightness, but the power bank cannot even power a single LED well enough to see properly on the webcam.
It's becoming really frustrating, any idea what's happening? Best solution?


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6 years ago

A single IR LED connected to a 5V source with no current limiting resistor is not showing vary bright cause you burnt it out. Without a resistor the LED will keep pulling current till it blows. Not to mention you where putting 5V into it. On the other had the IR LEDs may not be vary bight to start with or your camera isn't able to pick up that wavelength or IR vary well.

If you want motion or head tracking for a good price your best bet is using a Wii mote as your tracking camera. Look it up. There is software available and the PC can connect to the Wii mote over Bluetooth. Then you should have no problems tracking any IR LEDs you want to use. Besides if you want it small then use coin cell batteries to power the LEDs.


6 years ago

I should also add, this power bank charges my phone at 5v 500mA perfectly.