Strange USB Connector?

erco · 2013-07-28 19:23

I was about to recommend this cute little breadboardable power supply. 5V, 3.3V, USB connection, seems a bargain at $2.39: http://www.ebay.com/itm/Prototype-Shield-Signal-Generator-Network-SD-Card-Module-Breadboard-For-Arduino-/310615193368?pt=LH_DefaultDomain_0&var=&hash=item48521bb718

(several items for sale there, you might have to select the power supply from the pulldown menu)

But the USB connection looks odd to me, being a type A female connector. To power from a standard USB connection would require a cable with a type A male at both ends. Never seen one of those cables. Mightn't that be a dangerous cable to have if you randomly plug 2 USB devices together?

Such a cable does exist: http://www.ebay.com/itm/USB-2-0-Type-A-Male-to-Type-A-Male-Extension-HighSpeed-Cable-15-ft-15-feet-Black-/261223217010?pt=US_Drive_Cables_dapters&hash=item3cd21df772

Is this odd? Maybe that's why the board is such a steal... but still might be good for someone using a wall wart input.

Duane Degn · 2013-07-28 19:41

Don't you think it's intended to supply power to a USB device? Like those wall warts with a type A connector.

You plug your normal wall wart into the board than then you can use your board to power your QuickStart board through its USB connector (with appropriate jumper on QS).

I doubt the USB connection is intended to be used for power in.

Nevermind. I didn't read the description well enough. You're right. Weird. (Not weird that you're right, it's a weird connector to use on the board.)

Sapphire · 2013-07-28 19:55

Just like those Parallax BS2 OEM boards with male DB9 connectors?

erco · 2013-07-28 20:11

Sapphire wrote: »

Just like those Parallax BS2 OEM boards with male DB9 connectors?

We gotta get those kids together!

xanadu · 2013-07-28 20:35

erco wrote: »

We gotta get those kids together!

It's hard to read when you choke on water and it comes out your nose. Thanks!

erco · 2013-07-28 20:50

OK, I'm not crazy. But seriously, couldn't the average person do some damage with a male/male USB cable?

That sounds bad for a variety of reasons.

xanadu · 2013-07-28 21:15

It's possible the description is wrong, if it is correct that is a poor design. I think the barrel jack is the input and the USB port is regulated 5v out like a powered USB hub minus the data pins.

erco · 2013-07-28 21:34

We'll see. I ordered one, for better or worse!

xanadu · 2013-07-28 21:36

Actually I take the poor design comment back. If that had a USB B connector on it, it would be very easy for people to power it from a computer USB port, and possibly overload that USB port (>500ma). USB male A to A patch cables are rare so they probably bank on the fact you would only use one with a special external power source and not a PC.

Possibly...

erco · 2013-07-28 21:46

Helpful review at http://www.petervis.com/Raspberry_PI/Breadboard_Power_Supply/YwRobot_Breadboard_Power_Supply.html but no curiously, no mention of said USB connector. I do like the fact that it is sized perfectly to straddle a 400-hole breadboard.

xanadu · 2013-07-28 21:56

That review says the maximum output is 700ma which is too much for standard USB which is why they use a non-standard connector.

erco · 2013-07-28 22:26

IIRC, USB 1.1 was 500 mA. USB 3.0 is up to 1.5 A. http://en.wikipedia.org/wiki/USB

xanadu · 2013-07-28 22:44

The connector is definitely USB 2.0 which is limited to 500ma maximum.

ajward · 2013-07-29 01:57

I have a USB cable with two male "A" connectors. It came with an external drive enclosure I bought several years ago.

@

RDL2004 · 2013-07-29 03:47

I have several A to A male cables. Granted that A to A is not common, but M to M is pretty much what all USB cables are. Maybe they just got a good deal on a bunch of the larger type A jacks, so used those instead of mini B or whatever.

The 700 mA maximum is probably dependent on how the board is being powered. I do wonder if the USB port is switched out of the circuit if power is coming in from the DC coax jack. If not there is a possibility applying excess voltage (> 5 V) to whatever is attached to the USB jack.

zappman · 2013-07-29 04:11

I also have a couple of "USB male A to male A cables" bought them at a Dollar Store.
I thought I was buying "USB male A to female B cables" like I had done before.
I didn't notice what I really had, until about a week later when I tried to use one of the cables.

mindrobots · 2013-07-29 05:03

I like xanadu's theory in post#9. Makes perfect sense to me (that should set off alarm bells with some of you!)

RDL2004 · 2013-07-29 06:14

3. Input voltage: 6.5-12 V (DC) or USB power supply

I'm pretty sure this means it could be powered from a computer's USB port if that's what you want to do. By powering it from a PC you may not be able to draw over 500 mA (but don't bet on it, the 500 mA "standard" is not all that standard). I think the 700 mA maximum they refer to is what the circuitry on this board is capable of. That's why I hope the USB jack is disconnected if using the DC input jack, otherwise potentially those 6.5-12 volts could be fed into the PC or other USB power supply if both are hooked up at the same time.

erco · 2013-07-29 06:55

With all this chatter, surely I'm not the only sucker who ordered one. So fess up, Shirley! And share your findings. The world waits.

DaveJenson · 2013-07-29 08:31

I bought a couple of these. I assumed the USB port was to output power to USB powered devices...
When I get home from work, I will take a closer look at them.

erco · 2013-07-29 08:52

XLNT. You're a good man, DaveJenson!

tonyp12 · 2013-07-29 09:14

It's 5V regulated out, you could power your Quickstart if you put a 0-200ohm resistor between
/USB_PWR_EN (6th pin from the right side, upper row) and Ground(1st pin from the right side, lower row)

Or use FTDI FT_Prog Utility to change cbus3 to always low by setting it to: BitBang RDn
At the same time also change Max Bus Power to 500mAmps (as mine had a 90mA setting)

http://www.ftdichip.com/Support/Utilities/FT_Prog_v2.8.2.0.zip

I also tested that you can power the board through usb too ,if you have proper usb cable/y-splitter you get 5v (eg Vin) and 3.3v out
But some usb hosts will not release over 100mA without enumeration.

CuriousOne · 2013-07-29 14:18

I'm VERY SCEPTICAL when things come to buying something power-producing on ebay. All my past experience never had any reliable/positive results.

Step up/step downs quit working, sometimes with full input voltage applied to output. Once, even step up went crazy and delivered 9 volts instead of 5.
AC adapters explode, batteries won't recharge, buzzers wont buzz and so on.

So for active electronics components from ebay, I only buy from u.s. suppliers and only if they sell some NoS or other remnants made by know brands.

erco · 2013-07-29 15:08

Not sure if I mentioned my USB story from last year. There was a brief burning smell shortly after turning on my computer, couldn't track it down for a while. But later I noticed that the front multimedia card slot (USB, SD, xD, etc) stopped working. One of the twins found that they could shove a dime into the SD "coin slot", which shorted out and burned the trace off the PCB when I turned it on. I soldered on a thin piece of enameled wire (a virtual fuse, like the PCB trace) and all worked again.

Kids do the darndest things!

Card slot was one of these (and all the damage was contained inside): http://www.ebay.com/itm/8-in-1-Multi-Card-Reader-USB-SD-XD-USED-but-Works-FROM-a-Compaq-HP-computer-/161074837677?pt=US_Memory_Card_Readers_Adapters&hash=item2580cef8ad#ht_26wt_917

blittled · 2013-07-29 19:09

erco, I have one of those bread board power supplies and it works well but I haven't tried the USB connector because I don't have a A to A USB cable

DaveJenson · 2013-07-30 08:34

I checked mine when I got home. That USB port offers power for (for instance) the QuickStart board. So it seems to be a power output port.

erco · 2013-07-30 20:17

Thanks for all the help, folks!

Same item for less, just $1.38: http://www.ebay.com/itm/MB102-Breadboard-Power-Supply-Module-3-3V-5V-For-Solderless-Bread-Board-HS-/221250141932?pt=LH_DefaultDomain_0&hash=item3383893eec

xanadu · 2013-07-31 20:47

DaveJenson wrote: »

I checked mine when I got home. That USB port offers power for (for instance) the QuickStart board. So it seems to be a power output port.

So it is a typo... go figure. That was my first guess, do I win anything?

erco · 2013-08-18 20:23

I got two of these. Not exactly what I expected, but still useful, especially at the bargain price of $1.38. In summary:

Two voltage regulators on a board sized to fit into standard breadboards with two power rails on each side. 5.0V supplied to female USB connector. Jumpers allow independent selection of 5.0V or 3.3V to each rail. Master on/off toggle switch cuts power to everything. Power connection is a standard coaxial jack, center-positive. Single green LED power on indicator.

NOT LDO regulators. Keep the voltage input above 7V. I used 7.5V.

My quickie tests show that 6.0V input yields about 4.5V output, not 5.0V.

4.5V input would not quite keep the 3.3V regulator happy, it gave under 3V output.

Edit: There are at least two different boards, minor differences between them. My tests were on the $1.38 board in post #37, which has a slightly different shape and layout than the purely rectangular one in post #1.

Strange USB Connector?

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