breakout board 5v supply question and picture

**stan kern** · 02-09-2011, 9:35 AM

can anyone suggest where the usb cable gets its 5v supply with a cable like the one supplied,the male usb goes in the board but where does the other end match up to before i have to do some mods(cutting)

**Rob Wright** · 02-09-2011, 9:43 AM

What BOB is that? I can't say that I have seen it that way before with a Male USB and a Male Jack with the USB being on the board - but some BOB's use a USB from the PC to power the BOB. You couldn't use that cable - but that's what I have seen in the past. One supplier gives you the option of USB to power the board, screw terminals from a power supply, or a female "jack" on the board to accept a plug similar to what you have there.....

**Dan Hintz** · 02-09-2011, 9:44 AM

I'm not sure I understand the question... it appears the USB jack supplies 5V to the barrel jack, which is used to power something else.

**stan kern** · 02-09-2011, 10:45 AM

yes its a strange cable ,does look like the BOB supplies 5v but its is a 5volt input ,diagram just shows the usb being the 5 volts in,no terminals
I may just use a 2 male ended usb cable for the pc to the BOB,as i don't want to mess with polarity issues
thanks for the answers

**Dan Hintz** · 02-09-2011, 11:41 AM

If the barrel connector is an input, the only thing I can think of is it was designed to be used with swappable power supply wall warts (I have one from Radio Shack... it came with multiple barrel connector sizes, you just swap it out. I have also seen a (relatively) few wall warts that have an embedded male barrel connector, similar to what you would find on the back of a cordless drill... that plug would be what those PSs use.

**Michael Simpson Virgina** · 02-09-2011, 4:01 PM

If its an input then make sure you purchase a regulated 5v. Something is definitaly missing from this picture. look around on the BOB for a small hole that the barrel end of the cable plugs into. That makes more sence to me.

**Gerry Grzadzinski** · 02-09-2011, 5:25 PM

Looks like the wrong cable to me.

**Gene Crain** · 02-09-2011, 7:15 PM

http://stores.ebay.com/HUBBARD-CNC-INC

this guy can help you, send him email...

**Mike Heidrick** · 02-09-2011, 8:28 PM

The cables barrel plug should be marked with a diagram that lookx something like -C+ or otherwise showing you which part of the barrel plug is DC positive. Then use a volt meter's continuity feature and find which USB pin corresponds to that part of the barrel connector. Don't have a volt meter? - make a simple circuit with a battery and a flashlight bulb and use the process of elimination until you light up the bulb. Or just go buy a meter LOL.

**Mike Heidrick** · 02-09-2011, 8:30 PM

http://www.accesscomms.com.au/reference/usb.htm

pin outs and pin function listed there - scroll down

**Dan Hintz** · 02-09-2011, 9:02 PM

Mike,

I don't think it's an issue about determining what positive/negative... the issue is more why that odd cable (and connector combo) is being used to power the board

**Mick A Martin** · 02-09-2011, 10:53 PM

Hi Rob,

Are there any connections on the back of the breakout board? name or part number ....... anything

Mick

**james mcgrew** · 02-10-2011, 7:48 AM

not sure i understand but isn't there a 5v suppy from the computer in the 25pin cable

**Rob Wright** · 02-10-2011, 8:50 AM

Originally Posted by james mcgrew

not sure i understand but isn't there a 5v suppy from the computer in the 25pin cable

some BOB's use their own supply to fully opto-isolate the computer supply from the controller side of the supply. Others let you use your own 5v supply and are considered "buffered" BOB's because some Pport 's only put out 3.3v and cannot operate the logic on the board.

**james mcgrew** · 02-10-2011, 9:34 AM

thanks i had an older cnc a few years ago and the 5v was pulled from the port

thanks

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