The NEW Build Your Own Arcade Controls

Main => Everything Else => Topic started by: markronz on April 02, 2015, 01:15:29 pm

Title: Changing battery power to be USB power on small LED device
Post by: markronz on April 02, 2015, 01:15:29 pm
Hey everyone.  Just hoping someone might be able to lend me a little electrical knowledge.  I have this small device.  All it is, is when a switch is pushed it turns on a small LED light on the top.  Currently, it's battery powered by 3 AAA batteries.   I'd like to make it so that this thing is attached to USB to be powered instead.

Here are some pictures of the device.  Top View:
(http://www.markronsman.com/1.jpg)

Switch:
(http://www.markronsman.com/2.jpg)

Lit Up:
(http://www.markronsman.com/3.jpg)

Bottom Batteries:
(http://www.markronsman.com/4.jpg)

My real question is, is it as simple as chopping those two wires going to the battery bank and splice those over to a USB cable instead?  Anything I am missing?   I need to figure out what wires to use inside a USB too...

Thanks for any help!
Title: Re: Changing battery power to be USB power on small LED device
Post by: markronz on April 02, 2015, 02:04:13 pm
Someone directed me to this url. Should be very helpful!
http://www.instructables.com/id/How-to-power-nearly-anything-off-a-USB-port/#step3 (http://www.instructables.com/id/How-to-power-nearly-anything-off-a-USB-port/#step3)

I think I'm just going to try it out.   Worst case scenario, I just have to replace the LED!

Title: Re: Changing battery power to be USB power on small LED device
Post by: RamjetR on April 02, 2015, 08:25:56 pm
The quick answer is just chop the USB lead and connect the 5V and GND to the + and - of the battery contacts. The reason is simply that 3x1.5V is 4.5V and the additional half a volt will make at most 3-5mA difference to the LED. You won't even see a difference to the brightness. You'll be fine.
Title: Re: Changing battery power to be USB power on small LED device
Post by: danny_galaga on April 03, 2015, 04:28:12 am
Quote from: RamjetR on April 02, 2015, 08:25:56 pm
The quick answer is just chop the USB lead and connect the 5V and GND to the + and - of the battery contacts. The reason is simply that 3x1.5V is 4.5V and the additional half a volt will make at most 3-5mA difference to the LED. You won't even see a difference to the brightness. You'll be fine.

 :stupid