Picture of USB tester

This simple device allows you to check the correct working of the USB ports of any computer, using a green led and message from your operative system.
It will allow you to test the proper assembly of any port without risking any expensive device.
If you normally work fixing computers this is a must in your tool kit.

Ps: I'm from Argentina so let me know any grammar mistake

Step 1: The circuit

Picture of The circuit

The circuit is very simple using only some discrete components.
The operation is simple, you connect it to the USB port, if it's okay, the green LED is lit in all its intensity and you will have a message from your operative system telling you than a USB device has been detected. If the polarity is reversed the red LED is lit in all its intensity. Any other combination causes lit one of the two LED but very dim.

You will need:
The PCB (see step 2)
The USB connector (see step 3)
Two 22K resistors
One 1k resistor
One 100 ohm resistor
One 1.5 k resistor
One 3v3 zener diode
One 1N4148 diode
Two leds (green and red)

The diagram was extracted from this forum (in Spanish): http://www.ucontrol.com.ar/forosmf/proyectos-en-general/probador-usb/

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Hey Bruno, thanks for sharing, this is exactly what I was looking for. I'm planning to use a bicolor led, the one which turns green or red depending which way the current flows. anyways, I'm from argentina too, and I have a small grammar correction for you, "Try not to overheat the diodes and not allow shorts in the PCB." should say : "Try to not overheat the diodes and don't (or do not) allow any shorts in the PCB" brunoip, you are legendary , here in Argentina. also se dice easy to solder, weld is for big uniones.

Did you design the pcb by yourself?
brunoip (author)  TheGimpAddict5 years ago
Yes, I did.
Using PCB Wizard.
AtLarge brunoip1 month ago

Thank you Brunoip. I made mine on a breadboard. Seems to work work fine although I only had 15k resistors on hand not the 22k you had specified. Need you to design one for testing a USB 3.0 port now. :-)

MildredGreen2 months ago

very good article for IT students like me :) thnx

azimovismayil9 months ago

very good.I could make it at 4th time :D

Can anyone please tell me the working principle of this USB tester
cholerah212 years ago
sir laptop got like this http://www.usbman.com/Guides/Belkin_F3U001.jpg? hhh
m1s73r3 years ago
When does the red LED light up?
Q: "When does the red LED light up?"

A: when USB polarity is reversed. this little mistake can easily be done on auxiliary or remote ports on desktops. those are ones that connect to motherboard through cable, for example:

plugging in camera or phone etc is an expensive way to test for this.
brunoip (author)  panic mode2 years ago
Pánico mode is right, Thanks for answering him.
bobbock4 years ago
What wattage resistors are you using, or does it make a difference?

I'm new to building electronic devices, and thought this would be a good one to try. When I went to get the supplies from my local store the first question they asked was what wattage. I bought 1/4 watt ressistors assuming that the voltage of a usb port is around 3.3 volts.

Thank you for the project and any help you can give.

ionic bobbock3 years ago
I believe they are 1/8W as they are the same size as a 1N4148 diode.
Wattage(sounds like cabbage, haha) doesn't really make a difference. In this case, seeing as you're using an USB port, with 1/8 you're more than fine. BTW USB uses 5 volts DC, usually @ 200-450 mAh.
os_sanches4 years ago
kkkk, muito bom.
jupiter24 years ago
good job!
beaver844 years ago
cool! :D
inhaos4 years ago
your schematic is cool
here is a perfect solution for you

mased0074 years ago
Hello. How to ironing method do? please
MoritzB4 years ago
Does it only check the voltage at the red and black connections, or does it also check the data lines?
dwyatt10454 years ago
I was wondering what the wattage is for the resistor
brunoip (author)  dwyatt10454 years ago
The smallest you can get.
1/4 or 1/8 watts shloud be fine.
There is no problem if you want to use a big one.
Regards, Bruno.
kenobr1004 years ago
how much did this cost to build ?
brunoip (author)  kenobr1004 years ago
I think it would be less than 2 dollars.
xtagz5 years ago
Sir.. Can u send me some other links for the PCB design..?? i cant DL the pdf file because im not a pro members... thanks..
You don't have to be a pro to get that PDF, did you try clicking it?

i need a circuit diagram.

can u help me.....
Taran6064 years ago
i dont have any 3v3 zener diodes any other parts i can use
Taran6065 years ago
Insted of using 5 resistors can't u use one 100 ohm resistor and one 46.5k resistor
brunoip (author)  Taran6065 years ago
Why explain and can u make a smaller compact version plz
Why explain abd can u make a smaller version that's more compact
Taran6065 years ago
In the 5th pic or the last one what are the extra leeds on the side for and are they inportant
brunoip (author)  Taran6065 years ago

Read the text:
"...to keep it firmly attached to the PCB"

regards, Bruno

Can I make a diagram because this one has to many resistors and I want to make it smaller
Leuh4n5 years ago
Fa, que trabajo posta :O
vhhp5 years ago
Brunoip, Good work. Liked your product and also your sensible replies. ..regards..
MASKELF5 years ago
excellent creation Bruno after creating it worked perfectly and as expected, is a great tool because I lost a USB memory port through a poorly connected, thanks! add a photo of mine
ozzymon5 years ago
buenisima la idea, increible tu ingenio!!! segui asi y ojala que tenfçgas suerte con tu usb tester!!
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