Is it me or is it USB?

Name: Is it me or is it USB?
SKU: 16907
Price: 9.99 USD
Availability: InStock
Rating: 4.71 (36 reviews)

(36 Reviews)

USB cable and human sanity tester

Designed by nerfhammer in United States of America

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USB cable and human sanity tester

More than 500 sold on Tindie! Now available in mini and original USB Smart vs Basic Look around you. How many USB micro cables that came with rechargeable devices can you see? Not all of them are the…

Smart vs Basic

Look around you. How many USB micro cables that came with rechargeable devices can you see?

Not all of them are the same!

Basic USB cables cannot transfer data and charge a device much more slowly. Smart USB cables can potentially charge a device several times faster, and there is no way to tell the two types of cables apart just by looking at them.

Data transfer test

Fictional testimonial

I was a vice president of a medium-sized regional bank, working with my son on a small weather station project powered by a Teensy microcontroller. That was three weeks ago. Now I travel from town to town taking odd jobs and wandering the streets muttering obscenities under my breath to no one in particular, the words "Error: Serial port not found" ringing in my ears. The brisk-stepped respectable member of society I was just a few weeks ago would have avoided the crumpled, shambling semblance of my form from his gaze, with the temporary brush of awareness not of contempt but of disdain and quiet avoidance. Sometimes in moments of clarity I think of my family. I wonder if it was just the USB cable I was using. Could this tragedy have been avoided?

Now there is a way!

If you unwittingly try to use a lower-quality, basic USB cable to program a USB serial device it can be a savagely frustrating experience. Mistaking a basic USB cable for a smart one is (probably) a leading cause of mental health issues for electronics enthusiasts. Lower quality cables generally have no markings indicating this.

The "Is it me or is it just USB" tester shows you which lines have actual continuity in a USB micro cable. Basic cables will only light up the LEDs for the V+ and GND lines, but smart cables will light up all four. I also broke out test pads so you can test resistance or impedance of the a cable with a multimeter should you want to do so for some reason. The tester also has protection diodes to protect against anything unexpected happening should you leave one end of the cable plugged into a USB host port (which is not the intended usage of the tester).

Save your sanity today! Use this tester!

USB fast charging test

What if you don't use USB cables to program serial devices, you just use it to charge your phone or tablet? Surely, you need not have to worry about whether the cable has data lines, right? You can just go on drinking your designer coffee, without having to worry about milliamps and coulombs and so forth?

Wrong.

Fictional testimonial

I am a rescue helicopter pilot working for a wildlife protection agency. Due to the way several government forms were filled out, I have to communicate with the ground rescue team via snapchat on my personal cell phone. I am usually leave my phone to charge for an hour before taking off. One time I lost the cable that came with my charger and had to borrow a USB cable from my buddy Chip's USB powered desk dehumidifier. Though I used the same wall plug, by the time I had to take off, my phone was only charged 35%, which means I would barely have enough charge to use Tinder while in the air. Snapchat's video stories are very demanding on my phone's battery life and I almost ran out before I had to land. That was, as they say, too close. But I don't understand why my phone wasn't able to charge so quickly. What happened?

Smart charging

Basic USB micro cables are made without the D+ and D- lines in order to save a few cents in manufacturing. The justification is probably that most people won't ever try to use them to transfer data. Well, so what? The problem is this cost-saving measure means such cables can't actually charge devices as quickly.

Some smart devices such such as many Android smartphones, will attempt to negotiate with a charger for the amount of current it can accept. The exact details [1][2] of how this works are gory, but it needs the data lines to be able to do this. While the cable that came with your smart device is presumably compatible, a USB cable borrowed from something else or a cheap one you bought off of Amazon may not. If the charge rate isn't negotiated, it will fall back on the USB 2.0 default of 0.5A. But your phone may be able to charge at 1.5A or 2A. This means that using the wrong kind of cable your phone could charge up to 3 or 4 times slower than it would otherwise.

Using this USB continuity tester you can tell the difference. If all 4 LEDs light up, the cable is a smart one that will be able to support the faster charging protocols if your device supports it. If only 2 light up, it's a basic one that cannot. If you replace such cables with smart ones and if your device and charger support compatible smarter charging protocols, you may be able to charge your phone several times faster.

Usage instructions

Take both ends of the same USB cable under test and plug each corresponding end into the USB type A and micro type B ports. Do not leave the cable connected to another device while it is connected to the tester.

If the data lines work, the included battery will light up the corresponding LEDs in the "smart" section. This means the cable should be able to transfer data and to charge a device with higher power.

You can also tell if the USB cable is defective or worn out internally if one of the "basic" V+ or GND LEDs don't light up or if any of the LEDs flicker or switch erratically when the cable is handled. If this happens the cable under test is probably not suitable for use and should be discarded.

For more advanced users, test pads are exposed so you can easily measure the resistance, inductance or other properties of a USB cable using a multimeter. You'll presumably want to remove the battery from the tester while doing that.

Addenda

For a very nice 3D-printed case design, see this post.

Disclaimers

The protection diodes and the USB spec are designed to prevent anything from happening as a result but both ends of the cable under test should be detached from any computer or charger before being plugged into the tester.

The tester is not conformally coated.

I invented the terms "smart" and "basic" for the purposes of description. What I've called "basic" are sometimes called "charge-only" but as described above they actually are worse at charging, so that term is misleading. It has been argued that these cables are essentially "fake" USB cables since they don't adhere to any USB spec and obviously cannot really bus serial data.

Testimonials and health claims in the product copy are intended as satire and should not be taken seriously.

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Review Breakdown

Average Ratings

Product: (4.92)

Documentation: (4.47)

Shipping: (4.89)

Communication: (4.56)

Rik | March 16, 2023

Great tool

This really takes the guessing out of the appropriate cable to use. Very simple to use and a really robust bit of kit.

Valerie | Feb. 3, 2022

Shipped and Received in Canada in record time

Tested the usb cable i bought this for and apparently its me.. Tester will come in very handy and I really love gadgets

Henry | Nov. 28, 2021

A massively useful tester to have on hand

The tester arrived faster than I expected and works great!
It would have been nice if the included explanatory business card had included info on *exact* meanings of the V+ and GND lights. I ended up needing to do some Googling when I first encountered a cable that only lit V+.
Otherwise, no complaints. Super handy.

Terence | Nov. 4, 2021

Very useful device -no need for documentation

An easy way to separate power from data transfer USB B cables since they never come with markings. Doesn't accomodate USB C cables however but appropriate adapters are available.

Kevin | Sept. 14, 2021

Works Great - Type A Port Tad Fragile

Works great, so happy to have gone through the pile and eliminated all the annoying power only micro USB cables. My only complaint would be the type-a port can be a tad fragile, keep an eye on it with shorter cables that you dont pull on it too much. I shored it up with some hot glue and its all good.

William | April 27, 2021

Excellent product

Great little tool. Service was quick and I've already sorted all my cords. I always use a 'charge only' cord when at a public charging station.

Luis Fernando | April 7, 2021

Useful for test my cables

It works incredibly well, I don't know how this is not on sale everywhere. Very useful to test my USB cables. Maybe we need a USB C version in a future (My gf told me)

Mike | March 4, 2021

Awesome product, does exactly what it's designed to

So easy to use and it works exactly as expected. There are larger products you can buy from China that come with many ports of all types, but those require a power source. With this one, you can do all the testing wherever you have the cables and it works fine with adapters. You'll just need a Micro-USB-M to Mini-USB-F as well as a Micro-USB-M to USB-C-F to cover all of your needs. I am shocked just how many of my cables are "charge only". No wonder I have run into issues a number of times. This device is a must-have.

Cameron | Feb. 23, 2021

Super Useful Tool

It's ridiculous that cheap micro USB cables will often leave out the data wires to save a fraction of a cent. This little tool quickly identifies the offending cables, and has definitely saved me frustration.

Andrew | Feb. 9, 2021

USB Cable Judgement Day!!

If you've got enough USB cables around that there's no point in having the 'dumb' ones around...this baby will be the judge, jury, and you're the executioner. I went through all of mine and did just that. Now I know that if I grab a cable and hook it to a microcontroller or something, I won't be pulling my hair out wondering what the hells going on. Love it. Worth every penny. Shipped fast too.

Question though, with an adapter, will this work with non micro-USB cables or USB-C cables?

Response from nerfhammer | Feb. 9, 2021

I would expect that it would work for Type A and USB mini via adapter.

It may work partially for USB-C but not accounting for the redundant pins USB-C has (multiple pins connected to the same line; in theory only a subset of the pins for a given line could be broken) or the 6 additional data lines added in USB-C.

A. | Jan. 26, 2021

Works like a charm!

Ordered on the 20th, shipped the next day, arrived in Yurp on the 26th. Excellent service!

The device is simpel enough in operation: all lights, power + data; two lights (the right ones, natch), just power. Any other number and combination of lights, throw the cable out! Great!

Andrew | Jan. 12, 2021

Definitely a Must-Have Device

Great little circuit. I had been frustrated transferring files from my Win 7 box to my Kindle and it was all because I had the wrong type of cable, i.e., a charging only cable vs a data and charge cable. I bought two of these so I could give one away to a friend. A video is available for this device.

Scotty | Jan. 9, 2021

Awesome little tool!

This is really great for quickly taking the guesswork out of programming devices with potentially dodgy micro USB cables. Can't wait for a USB-C version!

Michael | Jan. 6, 2021

Nice, one trick pony that did not empty out my bank account.

I have some cables that are questionable. This helped me out nicely. I was able to get rid of some dead/broken cables.

Micah | Jan. 4, 2021

Fantastic product -- Every USB cable I own has been checked

There's a glut of shoddy USB cables on the market. Almost every device these days includes one in the package. This is the perfect tool to check (and as often necessary, apply the mark of shame) for cables that don't meet the spec.

Stephen | Jan. 2, 2021

Great gift for techy friends

I bought 4 of these for Christmas gifts. They were a real hit. I had two recipients tell me they were used the day after Christmas to test their cables. I know one of them was placed into a "Go bag" to be ready for use anytime. Regardless of price one of the best received gifts I've given in years. The device can find cables that are defective and determine if a cable is power and data on just a power charging cable.

Günther | Dec. 25, 2020

Great Product.

Thanks. Finally I had a chance to remove all my old cables that are only good for low power charging. Quick delivery to Europe.

Klaus | Dec. 25, 2020

Great Product

Great Product for checking Cable and find some that will good work with Garmin Edge Cycle Computer. Delivery to Germany was also good and quick.

Tom | Nov. 2, 2020

Excellent. Exactly what I wanted.

It does one great thing. Weeding out impostor USB cables. Shipping, documentation (not necessary) and communication (why?) were beside the point. Would definitely buy again.

Alexander | Oct. 8, 2020

It should have been made a long time ago.

I have a bunch of USB cables from trade shows and determining which ones can be used for transfers is extremely useful. This came complete with a battery so I was able to use it right out of the box, er envelope and its very easy to see which cables are good.
Too bad we're moving to USB3 cables now, but as long as I have raspberry pis and similar devices (which should be a long time) I will get lots of use out of this doohickey!

Andrew | Sept. 14, 2020

Handy bit of kit.

Does exactly what it says on the tin. It would be great to have something this simple but capable of testing usb to type b, c, micro usb etc all in one package.

Chris | Sept. 7, 2020

I knew it was USB.

This seemingly "obvious" device is going to save way more man hours than the price of admission! This particular device will never leave my desk or desk drawer, because I'm reaching for it at the first sign of oddities from now on.

Aaron | Sept. 4, 2020

Exactly what I wanted.

Everything I wanted and nothing I didn't. Already used it to go through my stash of cables and found several that were either making intermittent contact, or were completely shot.

The only critique I have is that the pictures show a USB-A port that has through-hole soldered supports, and the unit I received has surface mount soldered supports. I'm concerned this might not be as sturdy as the through-hole model. If the pictures were updated to reflect that change I would've had no reason to be concerned, and would've been 100% satisfied instead of just 98% satisfied.

Great product. Would buy again.

Gordon | Aug. 23, 2020

Very Handy Little Tester

Nicely executed. I've used it several times to find a proper cable for various applications. Now need a similar one for USB-C.

Lawrence | July 25, 2020

I am so glad I bought this!

30% of my micro usb charging cables were “slow charging.” I got rid of them and am now assured that when I need a charge that it’s at the fastest rate possible because my time is valuable

Alan | March 18, 2020

Great product

Simple, easy to use, works as described.
A real pleasure to put aside cables that will not transfer data or fast charge.
This little board does it really nicely.
Would love to have usb c version.
Thanks

Marc | Jan. 7, 2020

Good product. Would recommend.

Works great. I would like to put it inside of some kind of shell or case while being used. I'm afraid that I'm going to break it when plugging and unplugging cords.

Katherine | Dec. 26, 2019

Sanity-preserver!

This is great for those times when you really cannot see why a microprocessor can’t be flashed - and it turns out to be the cable. Much easier than tagging every usb cable. Those “no data” cables are good when you want to be sure nothing is downloading data from your device while charging. This device is a useful piece of kit. Bought one for me and one for my son.

Alexander | Dec. 26, 2019

Handy device

When I saw his device it was an instant buy. I have accumulated so many cables and run different hardware workshops where this is incredibly handy. Works great and everybody that has seen it loves it.

Carlos | Dec. 9, 2019

So useful ...

It's a perfect little gizmo for what it does. Gonna use it to cull some cables from the herd.

OMG, it could be a necklace or hat brim thing too! Just gotta protect the battery side from human contact.

David | Dec. 5, 2019

Perfect little device

Plugged in a few cables and discovered one was intermittent and another had a line or two open. So much better than producing wear on an expensive phone port and waiting for it to say slowly, rapidly, and wondering what's going on.

James | Nov. 27, 2019

Simply, awesome.

This product is one of those projects I wanted to build for the longest time. But, for $12, why not just get a pre-built module. Maybe you are like me and have a box of USB micro cables that came with various gadgets. A few minutes with this tester will let you know which ones to keep and which to strip for their wires. Any time I have issues with a USB device, I double-check the cable to make sure data and power are connected.

No joke, I liked this board so much, I bought a second. One stays in my box of USB Micro cables and the other on my bench. If you've made it down to the reviews section, you're thinking, "do I really need or want this?" The answer to both is yes. Click 'Add to cart' right now. :)

Keith | Nov. 13, 2019

The right tester at the RIGHT time!

I have drawers full of old USB cables and was having a terrible time figuring out which ones were good. Stumbling into this tester saved the day. It does EXACTLY what it says it will. Thanks for the great product and known "GOOD" cables!!!

George | Oct. 4, 2019

Great tool

This is a very useful device! It clearly shows connectivity on each of the four wires in a USB cable. I'm not very concerned about fast charging, but I do hate debugging missing data connections on power only cables when uploading to micro controllers. I was able to quickly weed out the power only ones in my jumble of misc cables. I was also able to identify a flaky cable by noting the LED's flickering when I moved it.

Jude | June 19, 2019

Great USB breakout board

This unit was perfect in my quest to diagnose USB issues that were going on with a smart charger. This unit is well built and a great diagnostic tool.

David | June 12, 2019