USB Chainsaw

[Spehro Pefhany]

On Thu, 09 Jul 2009 10:07:35 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

Grant Edwards wrote:

On 2009-07-09, Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote:

Wow, 8lbs, 10" bar, but no mention of motor power, or how much current it
draws from the USB port

Say a 1/2HP motor should be okay from a USB part, given a
suitably low duty cycle (maybe 10 minutes of blood-spattering
mayhem per day).

Huh? A USB port that meets spec can provide 0.5A at 5V (2.5W).

$ units
2411 units, 71 prefixes, 33 nonlinear units

You have: 2.5 watts
You want: hp
* 0.0033525552
/ 298.27995

A USB port cat provide 0.0034 HP

1/2HP is 373W. At 5V, that's almost 75A. Short duty cycle
indeed.


Charge for months, and use for minutes!

It's not quite that bad.

0.0034/0.5 = 0.0068

0.0068 * 24 * 60 = 9.79 minutes per day (at full HP!).

One of the 36V nanophosphate packs (A123 cells) should do it.

 

[Jeßus]

In article <7bkdrkF23feepU1@mid.individual.net>, 5V@2.5A said...

Now here is a handy little tool for the handyman's tool box:
http://www.usbchainsaw.com/index.php

What's dangerous and swings from trees?

http://www.youtube.com/watch?v=8-bYnsLvHaU

 

On Jul 9, 3:11 pm, Don McKenzie <5...@2.5A> wrote:

   I see them in stores.  They are sold to transfer data between PCs.

I sell them also:http://www.dontronics-shop.com/usb-a-male-to-a-male-cable.html
these are straight through, whereas the transfer cable swaps rx and tx.

No it doesn't. There's only one twisted pair in a USB cable, and
reversing it's polarity won't do much good. You are probably
thinking of UTP ethernet cables from the days before autoswitching.

The data transfer rigs have a double-ended USB device in between, so
both computers can be the host.

In the age of USB-OTG interfaces some previously illegitimate cables
have become legitimate, but there it's the interface doing the
switching between host and device mode, not the cable swapping pairs.

 

[geoff]

cs_posting@hotmail.com wrote:

On Jul 9, 10:34 am, AZ Nomad <aznoma...@PremoveOBthisOX.COM> wrote:

You don't have one of those 75A usb ports?
No. They catch fire way too often. I upgraded to the 1000A version,
but the cables are still on backorder.

It's real hard soldering the 000 wire into those little connectors.
When I use my computer's front panel ports, the computer keeps
tipping over.

Get a clue! Instead of using a bigger cable to carry more electrons
at a time, you should try overclocking your motherboard so that you
can push them _faster_

Rare-earth crystals supporting your cable will make it conduct better.
Works for hi-fi...


geoff

 

[AZ Nomad]

On Fri, 10 Jul 2009 10:10:57 +1200, geoff <geoff@nospam-paf.co.nz> wrote:

cs_posting@hotmail.com wrote:
On Jul 9, 10:34 am, AZ Nomad <aznoma...@PremoveOBthisOX.COM> wrote:

You don't have one of those 75A usb ports?
No. They catch fire way too often. I upgraded to the 1000A version,
but the cables are still on backorder.

It's real hard soldering the 000 wire into those little connectors.
When I use my computer's front panel ports, the computer keeps
tipping over.

Get a clue! Instead of using a bigger cable to carry more electrons
at a time, you should try overclocking your motherboard so that you
can push them _faster_

Rare-earth crystals supporting your cable will make it conduct better.
Works for hi-fi...

maybe I can find one of them thar turbocharged cables

 

[Andy Peters]

On Jul 9, 6:47 am, Grant Edwards <invalid@invalid> wrote:

On 2009-07-09, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat> wrote:

Wow, 8lbs, 10" bar, but no mention of motor power, or how much current it
draws from the USB port

Say a 1/2HP motor should be okay from a USB part, given a
suitably low duty cycle (maybe 10 minutes of blood-spattering
mayhem per day).

Huh?  A USB port that meets spec can provide 0.5A at 5V (2.5W).

Only if it enumerates as a high-power device.

-a

 

[Mr.T]

"Robert Roland" <fake@ddress.no> wrote in message
news:70jc55l5903hp2r010q82m9ohlg3r4abum@4ax.com...

I have seent it once, on a hard disk enclosure for a 2.5" drive. The
cable even had three connectors, so you could leech power from an
additional USB port if the drive drew too much power for one port.

Fairly common for 2.5" external drives IME. The start up current often
exceeds 500mA.

MrT.

 

[Jasen Betts]

On 2009-07-09, Don McKenzie <5V@2.5A> wrote:

cs_posting@hotmail.com wrote:
On Jul 9, 3:11 pm, Don McKenzie <5...@2.5A> wrote:

I see them in stores. They are sold to transfer data between PCs.
I sell them also:http://www.dontronics-shop.com/usb-a-male-to-a-male-cable.html
these are straight through, whereas the transfer cable swaps rx and tx.

No it doesn't. There's only one twisted pair in a USB cable, and
reversing it's polarity won't do much good. You are probably
thinking of UTP ethernet cables from the days before autoswitching.

The data transfer rigs have a double-ended USB device in between, so
both computers can be the host.

In the age of USB-OTG interfaces some previously illegitimate cables
have become legitimate, but there it's the interface doing the
switching between host and device mode, not the cable swapping pairs.

Fair nuff!

Obviously I wasn't familiar enough with the transfer cable, however the
AM to AM that is used with the USBchainsaw is considered a special cable

The only reason I have ended up stocking them is because of designer faults.

some devices (eg PCs running linux) can (optionally) behave like usb devices
or like hosts and to connect them (as a device) to another host you'd need
an AM-AM cable,

I've never tried it, just seen the option "usb widget support" in ther kernel

 

[Peter Dickerson]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message
news:h373q8$ik1$2@reversiblemaps.ath.cx...

On 2009-07-09, Don McKenzie <5V@2.5A> wrote:
cs_posting@hotmail.com wrote:
On Jul 9, 3:11 pm, Don McKenzie <5...@2.5A> wrote:

I see them in stores. They are sold to transfer data between PCs.
I sell them
also:http://www.dontronics-shop.com/usb-a-male-to-a-male-cable.html
these are straight through, whereas the transfer cable swaps rx and tx.

No it doesn't. There's only one twisted pair in a USB cable, and
reversing it's polarity won't do much good. You are probably
thinking of UTP ethernet cables from the days before autoswitching.

The data transfer rigs have a double-ended USB device in between, so
both computers can be the host.

In the age of USB-OTG interfaces some previously illegitimate cables
have become legitimate, but there it's the interface doing the
switching between host and device mode, not the cable swapping pairs.

Fair nuff!

Obviously I wasn't familiar enough with the transfer cable, however the
AM to AM that is used with the USBchainsaw is considered a special cable

The only reason I have ended up stocking them is because of designer
faults.

some devices (eg PCs running linux) can (optionally) behave like usb
devices
or like hosts and to connect them (as a device) to another host you'd need
an AM-AM cable,

I've never tried it, just seen the option "usb widget support" in ther
kernel

There is no mechanism for transfering data directly between USB host
controllers. You can't connect one PC USB host port to a second PC and do
anything useful. Some controllers (not PC ones) ate OTG controllers which
means they can switch role from host to device but the OTG spec has its own
set of connectors and cables (there is an extra signal IIRC that designates
which end is the default host). An 'A' to 'A' cable would require a device
in the middle that appears as such to each of the hosts and defines some
means to pass data across.

I'm guessing that "usb widget support" for Linux means that the Linux system
has a USB device port and that a PC, or whatever, USB host can control it. A
photoframe might be an example of that.

Peter

 

On Jul 10, 7:50 am, "Peter Dickerson" <first.l...@REMOVEtiscali.co.uk>
wrote:

some devices (eg PCs running linux) can (optionally) behave like usb
devices
or like hosts and to connect them (as a device) to another host you'd need
an AM-AM cable,

I've never tried it, just seen the option "usb widget support" in ther
kernel

There is no mechanism for transfering data directly between USB host
controllers. You can't connect one PC USB host port to a second PC and do
anything useful. Some controllers (not PC ones) ate OTG controllers which
means they can switch role from host to device but the OTG spec has its own
set of connectors and cables (there is an extra signal IIRC that designates
which end is the default host). An 'A' to 'A' cable would require a device
in the middle that appears as such to each of the hosts and defines some
means to pass data across.

Yes, the ability to switch roles (OTG or otherwise) is first a
hardware capability, which then needs to be supported in the operating
system's USB implementation. The palm pre for example is believed to
have hardware which could be OTG capable (unless precluded by some
detail of PCB layout or PHY hookup) but the current software operates
only in device mode.

USB "gadget" is a linux device-side interface system often used in
embedded linux systems to emulate a USB mass storage device (point it
at a local partition or image file), provide a network interface over
USB, etc or I believe in the latest version potentially a
combination.

I haven't looked into it, but I think that in an OTG device "gadget"
would only handle the device mode - you'd switch it it host mode at a
lower driver level and it would presumably then behave like the linux
USB host implementation.

 

[Brendan Gillatt]

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Don McKenzie wrote:

Gilles Kohl wrote:

Hmm, isn't that device-side USB port the wrong type? Unless what is
illustrated in the photo is the downstream socket that can be used to
cascade several devices - hey, you could create a chain-saw-chain!

Very unusual, an AM to AM cable.
Only time I have used these, was when the designer did it wrong.

Don...

My knockoff chinese copy of the microchip ICD2 has one of those. I never
understood why.

- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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[Don McKenzie]

Brendan Gillatt wrote:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Don McKenzie wrote:
Gilles Kohl wrote:

Hmm, isn't that device-side USB port the wrong type? Unless what is
illustrated in the photo is the downstream socket that can be used to
cascade several devices - hey, you could create a chain-saw-chain!
Very unusual, an AM to AM cable.
Only time I have used these, was when the designer did it wrong.

Don...

My knockoff chinese copy of the microchip ICD2 has one of those. I never
understood why.

I'll bet it is an Olimex.

The reason it was done, was because he couldn't get a suitable housing
big enough to match the standard BM connector, so he used an AM
connector. Big mistake.

Now, he has the correct box, to match the correct connector. This was
done with, I think it was 3 products. All now corrected.

That was the design flaw that lead me to believe that the USB chainsaw
was a spoof.

Read further down for the "The chainsaw spoof!! Reaction?" thread.

Cheers Don...



--
Don McKenzie

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