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If you want to power from any USB port you come across, the limit is 5V at 500mA.
USB 3 muddies the water a bit with 900mA max.
Then there are ports that can be dedicated charging ports with limits up to 20V and 1500mA or more, but those require negotiation logic on your device end to get the port to deliver it.
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So, is there an option where you just splice the wires together and get power (like with AC), or does it always require negotiation logic?
Truth,
James
modified 12-Feb-21 12:48pm.
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Yes. All USB ports will supply 5V at a max of 500mA (900 for USB 3) without any negotiation.
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Is 5V at 900mA (If we're going to standardize, it might as well be on USB 3) sufficient for a reasonable number of household (non-computer related) tasks?
I'm assuming space heaters are out, but what about small lamps, fans, clocks?
Truth,
James
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Probably. The USB 3.0 spec has been around since about 2008, so motherboards would support for it for at least 10 years now.
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Clocks would be fine, Very small lamps (some LED Only?) and anything bigger than a novelty with a motor or tries to change a temperature will eat more amps than what USB ports deliver or cables are designed to carry.
I encourage you to continue your research though; please review motor home or camper power use - in many cases it's 24V DC and may answer many of your questions for how and what.
Or better yet, invent motors or heating elements that are actually practical and only require < 1 amp and 10V to run- that would make you a fortune!
Cheers, Craig
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You've got 4.5 watts. Check the power requirements for your devices. A 4.5 W fan isn't much of a fan. 4.5 W of LED light is bordering on the usable. A plain clock can easily run on 4.5 W, but if you are thinking of one with light and radio to wake you up to and animated display and so on, maybe it will break the power limit. Usually you can find the power consumption on some label.
And then: What you get without negotiation is five volts. If you want to adapt existing electronics, they may be built for two AA batteries, three volts, or for twelve volts. Some are for nine volts. So you will have to add some voltage regulator. Then you might consider adding a chip for USB power negotiation as well, and you will have the option for both higher voltage and higher effect.
I wouldn't have gone for USB as a low-voltage distribution system, though. Specifically: I am not going for it, I go for 12/24 V. I am in the process of stretching cables from the accumulators of my solar panels to sockets "all over the house". I go for far more robust plugs than USB-C; they will be XLR, probably 3-pin with ground, 12V and 24V. Before I start buying the sockets, I will again consider 5-pin, with a pin for 5V. The 12-to-5V converter will be right behind the socket, no 5V cabling, so maybe I rather put that converter outside the wall. I will put together various cables with XLR plugs for the wall side (usually the angled variant so it won't stick too much out), and various plugs / sockets in the other end: The common 12 VDC adapter plugs, the car cigarette lighter socket type etc. You can find most plug/socket types e.g. on Mouser.
At low voltage - definitely at 5V - the current for a given effect is high. The USB wires are thin. The losses are high. You cannot run long cables. That is why I added 24V alongside with 12V - actually, I've got 24V only from the accumulators to each floor, to a 24-to-12V converter. I am careful to minimize cable lengths: A "spine" along the middle wall through the house, fed from the middle. From the spine run "ribs" to the sockets, mostly on the center wall, or in a right angle out to a ceiling lamp. - Yet, I am using 4 sqmm cable for the spine, 2.5 sqmm for the ribs. I do not know the wire gauge used by USB-C, but it is a tiny fraction of this. For the cables, I might use thinner conductors; that depends on length and expected power consumption. Each rib will be protected by a fuse corresponding to the expected power drawn on that rib.
Note that the Wikipedia: USB-C[^] article states (in the Cables section): Cable length should be ≤2 m for Gen 1 or ≤1 m for Gen 2. This is usually good enough for equipment connected to the PC, but rather limiting if you intend to use it as a general power distribution system.
Bonus question: Why??
A couple reasons. We had a period of maybe 20 years with very few power outages - cables and transformers and whathaveyou up to modern standards. Then they started "optimizing", tuning the distribution for the absolute maximum utilization, and nowadays there are more or less zero safety margins. If an electrician sneezes at one power station, the fallout might ripple from one station to the next for twenty or thirty kilometers, maybe more. So the last few years, we have had a greatly increased number of power fallouts, the real cause far away, but the ripples are seemingly impossible to control. I do not want my house to get dark and communication to stop when this happens.
Second: In this country, you cannot do anything yourself on the 230VAC installation. You have to call an electrician for anything beyond replacing a broken fuse. For a 12VDC setup, you can put up a new lamp, or install a new outlet, yourself when you need it, saving at least a hundred Euro, maybe two hundred Euro.
Third: Adding computer control to a low voltage network can be done far more cheaply and easily, and in a far more compact way, than you can with a 230VAC network. And you can do it yourself.
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Too many small ends for someone to stick into the wrong outlet.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food
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I'm not really sure how to describe this, so bear with me...
I'm having this problem on my development PC.
- HP ENVY Desktop - 795-0030 CTO
- Intel Core i7-9700
- 32GB RAM
- 64 Bit
- Win 10 Pro
My PC is fairly new, probably a year 1/2 old.
Every few minutes I get what I can only describe as a "pause" that lasts for only a second or two. Everything stops - Mouse, Keyboard, music I'm listening to - everything. If I'm in the middle of typing, the key I last hit repeats across the page until the 'outtage' stops.
I have run the HP diagnostic tools on it and with no issues found. I don't see any problems in Hardware & Device manager, and no OS problems either that I can see. It almost seems like a USB problem, but I don't see anyting to confirm that.
So, I'm open to suggestion on this one.
Thanks
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
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If the pause doesn't happen during diagnostics (looping continuously), then it may be a driver or problem in Windows, or some other hardware problem. Windows can pause if the kernel is busy doing or waiting for something, completely unable to service any other interrupts until the current interrupt/operation is complete.
An I/O problem with a USB device may also be gumming things up.
Make sure all drivers are updated and see what happens. If the problem still persists, start unplugging things, one at a time, until the problem goes away.
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Thanks Dave
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
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Be sure you're not running multiple anti-malware programs at once.
The difficult we do right away...
...the impossible takes slightly longer.
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Yes, anything is possible. But you would be better contacting the manufacturer's support team for help. It is quite possible they can help with some remote diagnosis.
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Did you take all the "anti-static" precautions?
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food
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I am trying to access the GPIO of an embedded computer. The device was installed with Windows 10 Pro 20H2 x64 (not my decision). I installed the vendor specific drivers, and the GPIO device is shown with "Intel(R) Serial IO GPIO Host Controller - INT34BB" in the device manager.
I searched the internet and could find a “GpioTestTool” (https://github.com/ms-iot/samples/tree/develop/GpioTestTool) which I could compile on my development machine. After installing “Microsoft Visual C++ Redistributable for Visual Studio 2015, 2017 and 2019” (“VC_redist.x64.exe”) on the embedded machine, I could start the program.
It shows following error message:
“Error: GPIO is not available on this system”
This error message is also shown when I start the program as an administrator.
That is, the program fails to detect the GPIO.
Can you suggest any tools for trouble shooting?
Oh sanctissimi Wilhelmus, Theodorus, et Fredericus!
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My GLINK USB 2.0 extension cable isn't detecting External Hard Drive, though Pen drive is being detected. Plugging the EHD directly to the USB port of the CPU works fine. Only the extension cable isn't detecting it. How do I make the EHD work with the extension cable now? Or shall I try something else altogether? I'm running on Windows-7 32 bit. May I get some help, please?
Regards,
Priyam
modified 6-Jan-21 12:51pm.
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Hi all,
I am thinking of FPGA for an algorithm of mine, but lack of any experience with FPGAs.
The activity is number crunching, no fancy IO or A/D conversion.
I send a very large number, it crunch, and I get answer as a single number. One can think of it as integer factorization.
Crunching is made of large additions, subtractions, shift operations (*2 and /2), increments/decrements and logical operation and bits testing.
May be an embedded ARM processor to handle communication and data conversion.
Algorithm can be adapted for treading.
It is for hobby, so no real budget.
What hardware/software would you recommend ?
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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Hi,
Im currently making an app on windows forms trying to program a micro over UART. I can achieve it, although it is taking a long time to carry out the program. I have used stopwatches to determine it is my read function taking up the majority of the time. When i try to read the micros response from each command I have to wait for all of it, which is why im using a while loop in the code below, if the returned message size is not what i expect. What im wondering is, if there is any way to speed up this process. The response from the micro should be pretty fast, its running at a baudrate of 115200, meaning the whole 512 kb file should in theory take just over 30 seconds to complete, at the moment it is more than double that, at 80 seconds.
private string CheckResponse(int mSize)
{
string response;
int intBuffer;
intBuffer = ComPort.BytesToRead;
byte[] byteBuffer = new byte[intBuffer];
ComPort.Read(byteBuffer, 0, intBuffer);
response = Encoding.ASCII.GetString(byteBuffer);
while(response.Length != mSize)
{
intBuffer = ComPort.BytesToRead;
byteBuffer = new byte[intBuffer];
ComPort.Read(byteBuffer, 0, intBuffer);
response += Encoding.ASCII.GetString(byteBuffer);
}
return response;
}
Any help greatly appreciated.
Blair
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Member 14809996 wrote: The response from the micro should be pretty fast, its running at a baudrate of 115200, meaning the whole 512 kb file should in theory take just over 30 seconds to complete, at the moment it is more than double that, at 80 seconds.
You missed a couple things:
- In serial communications, every byte is preceded by at least a start bit and a stop bit, other settings like parity can add other delay. This make at least 10 bits for a byte transmitted, this make sending 512kB just under 45 secondes at 100% efficient.
- Any operation like reading the 512kB from storage will add delay.
- Any one serious with serial communication, for such a file, will encapsulate the data within a communication protocol to ensure data is not corrupted on the other side. This imply mode data to transmit and some time to ensure data integrity.
So 80 secondes is not that bad.
Patrice
“Everything should be made as simple as possible, but no simpler.” Albert Einstein
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One of my monitors is connected through a Display Port to HDMI adapter. Meaning that the graphics card outputs Display Port and the monitor takes HDMI.
I notice that the quality of the display is rather poor, and there is what looks like ghosting as you would find on an old analog television.
My question is, are there some display port to HDMI adapters that are better than others? Is this why some of them cost three times what others cost?
Or might there be something else wrong?
The difficult we do right away...
...the impossible takes slightly longer.
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Best way is to begin by test with another cable / then test with another screen or tv. You will have more information to search wich part has a problem.
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I have an OV2710 based USB camera (a low-light, as it should go inside a closed box). It is a UVC camera so no need for driver...
Connected the camera to a Win10 laptop - disturbing green shaded image (not fatal but all white/light colors are get greenish)
Connected to a Fedore 31 desktop - same...
Connected to a RPi 2/3/4 using a touchscreen - got a green-only shaded image... The image is clear and fast but green-only...
Anyone has experience with these kind of cameras? I just want to know if there is a way to fix that or should start to search for other camera (any suggestion to that direction is also welcome)..
"The only place where Success comes before Work is in the dictionary." Vidal Sassoon, 1928 - 2012
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