USB tester

Thread Starter

Wendy

Joined Mar 24, 2008
23,415
As near as I can figure USB outputs have following specs for power. I am not interested in data rates.
USB 2.0, 0.5A Voltage 5.0V+.25V -0.6 10Ω 2.5W
USB 3.0, 3.0A Voltage 5.0V+.25V -0.6 1.67Ω 15W

Over the years I have had several outputs that I questioned whether they were good or not in terms of voltage output. I'm thinking about building a tester based around the above specs. The resistors I show are to draw the maximum rated output for that port. I will be using this meter to give me a readout. I could not find any current specs for USB 1.0
 
Last edited:

Delta Prime

Joined Nov 15, 2019
1,311
Hello there.Birthday girl!:)
I could not find any current specs for USB 1.0
Battery charging was not an original feature of USB. There was no official provision before BC1.2 for charging the battery of a device that is powered off. By establishing a clear method of communicating the power capabilities of a USB port, many of these issues are remedied with BC1.2.
The USB 1.0 specification has been active since its release in November 1995. (The blind leading the blind) Products that were delivered to the 1.0 specification had no official logo associated with them. Many times the products did not fully meet the current-limit requirements, which usually was not a problem with the product connected to a PC. But, problems did arise when there were multiple products connected in a hub arrangement. With the release of the 2.0 specification, certified products will be marked with a logo. The certification promises to be more rigorous, and designers should expect to meet the requirements of the new specification.
 

Thread Starter

Wendy

Joined Mar 24, 2008
23,415
Money is scarce. There is also a certain pride that comes from doing things for yourself.
 

ErnieM

Joined Apr 24, 2011
8,377
How do you plan to account for the unknown but guaranteed to be variable current drawn by your uncalibrated meter of unspecified accuracy to... oh, I forgot what the intent is with all these unknowns.
 

SamR

Joined Mar 19, 2019
5,031
I have a couple of similar inline units. However, there is still a question about capacity and quality. It will tell you what's being used but not what is available current wise. Recently built an alarm clock w/ mp3 player and SD card instead of a buzzer. Has a Real time clock module and based on a Nano Arduino controller. It's powered from a USB port. Got it finished and plugged it in and the clock LED time display was doing something really odd. Kept flashing between the time and 66:65? Checked a few things and couldn't find a problem so shrugged my shoulders and left it plugged in. After a few weeks I had to move it and plugged it into a different USB source. Problem Solved! Apparently it was skating on the edge power wise causing momentary interruptions. Power not low enough to not work at all but enough to cause signal interruptions in its processing the display. This is just one instance of several USB problems. Computers with both USB 2 & 3 ports are not marked as to which is which and too lazy to search for my PDF manual every time I plug something in.
 

Teljkon

Joined Jan 24, 2019
267
Computers with both USB 2 & 3 ports are not marked as to which is which and too lazy to search for my PDF manual every time I plug something in.

you don't happen to be color blind do you. because the go to standard is to mark them blue red and gray 3, 2, 1.
 

SamR

Joined Mar 19, 2019
5,031
Not only colorblind but cataracts almost to the point of needing surgery... That may be so on the back of the computer chassis but not in other places such as my monitor, faceplate of computer, LED lamp base, or my switched USB breakout strip. Actually the USB ports on the back of my Alien tower are not color marked either. Most are USB 3 on the Alien but there are also some 2's.
 

DickCappels

Joined Aug 21, 2008
10,152
Or if you have an Apple CPU the USB ports are often in the back, thus hard to identify by color.

@SamR I think those of us who were blind with cataracts for a while and had our lenses replaced would urge you to have the surgery sooner than later. Being encumbered with "low vision" is a pain and having sharp stereoscopic vision wonderful if you were without it for a while. I don't think there is anything to be gained by delaying unless finances figure into it.
 

Teljkon

Joined Jan 24, 2019
267
Not only colorblind but cataracts almost to the point of needing surgery... That may be so on the back of the computer chassis but not in other places such as my monitor, faceplate of computer, LED lamp base, or my switched USB breakout strip. Actually the USB ports on the back of my Alien tower are not color marked either. Most are USB 3 on the Alien but there are also some 2's.
True not trying to be contradictory I personally haven't run into it enough that It would be an issue to me; but for 3 dollars! I am also truly a hobbiest and projects can sit for weeks if need be so. I wish you the best with your surgery. If I was a rich man I would offer you free help with the surgery for some mentoring in my journey, because I know how life changing it is. I had lasiks years ago and not having to fool with glasses is totally worth it at any level. Vision problems are no Bueno.
 

SamR

Joined Mar 19, 2019
5,031
FWIW After being told by my local optometrist he could do nothing for me until I had cataract surgery, I contacted the Mayo Clinic where I am already a patient. Mayo did a very thorough and much more intensive eye exam and their ophthalmologist said yes, I do have cataracts but not yet to the point of needing surgery and gave me a prescription for new glasses. That was over 2 years ago and see them yearly now for my eye exams instead of the local guy. Wife has already had both eyes done and when Mayo tells me it's time so will I.
 

Delta Prime

Joined Nov 15, 2019
1,311
Or if you have an Apple CPU the USB ports are often in the back, thus hard to identify by color.

@SamR I think those of us who were blind with cataracts for a while and had our lenses replaced would urge you to have the surgery sooner than later. Being encumbered with "low vision" is a pain and having sharp stereoscopic vision wonderful if you were without it for a while. I don't think there is anything to be gained by delaying unless finances figure into it.
@SamR I just recently went through all this with my father. It did not turn
out very well.
When a visual field test detects impaired vision, that’s already too late! You want to catch any signs of glaucoma much earlier than that.
I only say this because I went through it with my father and my father suffered optic nerve damage cuz the ophthalmologist was dragging his feet only treating his eye pressure! For five freaking years. I had to be his advocate in dealing with the insurance company and the physicians themselves.They have to go beyond eye pressure & directly target the retina and optic nerve.
If the ganglion cells and their axon fibers carrying visual information to the brain wither and die. There's nothing you can do about it but if they are damaged they can be repaired!
I had to insist my father get the proper
Treetment and testing be done . So talk to your doctor about two types of diagnostic tests they can give you one is.Adaptive Optics Scanning Laserophthalmoscopy
(AOSLO) specifically developed to provide extremely high-resolution images of the retina. And the second test leverages an optical coherence tomography (OCT) ophthalmoscope that uses visible light to image precise layers in the retina with unprecedented depth resolution and contrast. Because if your doctor is just concentrating on lowering intraocular pressure (IOP). Tell him you're going to start smoking marijuana inside the Mayo clinic!
 

Thread Starter

Wendy

Joined Mar 24, 2008
23,415
Ahem, I may indeed buy one of those other testers. But at this exact moment I am running into financial issues. Spectrum pulled money they should not have done. So I cancelled my debit card and am waiting for the new one to arrive. I'm not buying anything until I get a new debit card. Just the way life is sometimes.
 

SamR

Joined Mar 19, 2019
5,031
I don't have any problems with glaucoma. Just both myopia and presbyopia along with astigmatism and early-stage cataracts that the Mayo ophthalmologist deem to not quite need repair yet. I'm sure I could find a local ophthalmologist more than willing to take my money to do a lens transplant. Which is why I tend to put more trust in the staff at Mayo than locally. For those that don't know about the Mayo clinics you should look them up. I'm just lucky enough to be about 2 hours away from one that treats people from all the world. Every time I go there it's like a huge retiree gathering and you see folks who are in much worse shape than you are and give thanks that it's not you.
 
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