looks like he has set the N800 up as host/bridge to transfer the files from the N900. Pretty cool setup might have a go laters.

Although fun, this is not really the solution most are looking for! This is pretty much the same as plugging an N900 and USB flash/hard drive into a PC and dragging files from one drive to another, using the PC as USB host. I think most people here are looking to be able to connect USB devices directly to an N900, carrying a minimum amount of extra equipment.

I still argue that an N8x0 tablet is a minimum of extra equipment. You're just not going to find a PC this small anywhere else.

I'm pretty confident that the hardware limitations of the N900 mean that you're going to need the battery pack, power injection cable and the hub even if you manage to hack the N900 to be a USB host.

The N8x0 tablets are very compact little devices, and are much more capable and easier to hack than anything else proposed so far. The problem is finding one if you don't have one already.

Oh, and if you don't want quite so many cables, you can also push files from the tablet (and the connected USB device) to the N900 via bluetooth or wifi. I saw my N900 show up on the N800's file manager under bluetooth, even before I connected it via USB.

I'd have to add that an externally powered USB hub's with the correct wiring, resistors, etc are quite smaller than an N8xx - I've build several working prototypes in the past for various devices and they can be quite compact, let alone a fraction of the cost of an N8xx.

We may do R&D in getting USB host mode working on the N900; if and when that happens, we may very well decide to produce all in one hubs specifically for the N900 in the ~$20-25 range since we have the resources to produce them.

neopwn:

Oh man I would love one of those USB hubs for my N800, even if you never got a USB hack for the N900 working. Of course, the hack would be vastly superior.

It would be especially cool if the hub and a 4AA battery pack were combined together, making it completely portable, and useful as a charger for the N900 when on the road.

I have doubts the n900 usb is very usable as host. Presumably for their production kernel nokia fixed almost all problems they could find related to peripheral but did not prioritize host. I don't know how many changes there were between 2.6.28 and 2.6.29 for usb, but there are 30 patches for usb against linux-omap-2.6.29 in the openembedded kernel.

For the mean time (and when I get time) I'll do a write up and include schematics for you.. pretty much all of the components are off the shelf to DIY.

Cheers

Neopwn, I have electronics experience and would be very interested in building a proto and helping you test.

I also have a laser cutter and would be willing to build test enclosures for you. I can cut acrylic, plywood, etc. I'm very skilled at programming the laser.

Furthermore, if you get this working, I'll treat each member of your team to a free N900 stand or set of stands from my store -- just as a gift. This is my number one disappointment with the N900, anyone working on this is working to make the N900 what is should have been out of the box, and deserves to be rewarded.

I have used a similar arrangement for transferring photos from Canon A530 to Nokia N800, using Nokia 770 as host and running gphoto2 to transfer the files. (You may remember the abysmal performance of N8x0 in trying to run gphoto2.) For your purpose as well, there would be advantages in using the 770, notably:

1. You can buy non-WSOD Nokia 770 for about $55 (three recent auctions on eBay).
2. 770 does not automount, and it will therefore not attempt to mount devices and partitions that you would prefer it to leave alone. (Undisciplined automounting is one cause of the problems with gphoto2 on N8x0.)
3. Lack of internal power connection to the USB transceiver is actually an advantage if you are going to use power injection in any case. This isolation protects the host from fluctuations in the USB voltage line and ESPECIALLY from static buildup in the "ground" circuits. (Static buildup is possibly the biggest problem for camera connection to N800 host, i.e. not using 770. This varies in importance from one camera to another. With one of my cameras, the N800 is practically useless unless it has a genuine ground connection, whereas the other camera gives less trouble. It may be significant that the more sophisticated camera is the one that needs proper grounding. No doubt other gadgets also vary widely in the extent to which they create static buildup that could affect a USB host.)

The disadvantages of the 770 as host are:

1. The low-speed bus. This should not be a problem unless you want to play video via real-time USB transfer.
2. The need for a USB gender-changer and the poor quality of the few that are available. I have found that most problems with host mode on the 770 can be traced to sloppy receptacles on the gender-changer.

There is a prevalent myth that host mode on the 770 is difficult and mysterious, requiring use of the flasher utility. I hope that an earlier post in this thread has helped to dispel that myth. (Use of a USB keyboard could lead to problems if you activated host mode without the flasher. Those problems are avoidable.)

ADDENDUM 1, Feb 24: I don't want to pretend that grounding the USB cable is a workaround for the bug reported in https://bugs.maemo.org/show_bug.cgi?id=3281 . The ground connection seemed to improve things somewhat for a while, that is all. The unfortunate fact is that you can't rely on N8x0 as a USB host for many devices beyond the basic HID and Mass Storage. Nokia 770 is a better choice.

ADDENDUM 2: Nokia 770 has its own strangeness as host in this setup. After the N800 was plugged in, the 770's dmesg offered all three partitions of the N800's internal card as candidates for mounting (sda1, sda2, and sda3). From past experience with multiple Mass Storage drives plugged into a hub, I expected to see the external card offered as sdb1, but nothing came up.

P.S. 770 will also run the 0xFFFF flasher to update N8x0's rootfs without disturbing a customized initfs.

Hi, I have not read the entire 61 page thread. Is the USB OTG crippled on this device and I have fall back to a n810?

The n810 can use the OTG for a 100/10 RJ45 Ethernet connector and use a USB mouse/kbd, and even better I once found USB to serial port, which I use alot to connect to servers with. Sadly, the n810 lacked the TV-out.