3 Feb 2007
you read the reviews of the Nokia 770 Internet Tablet, you will find
that some of them
are not too favorable. While the new N800 has gotten somewhat better
reviews than the 770 did, a common criticism is the lack of a keyboard.
The Nokia Tablets do provide handwriting recognition, and not one, but
several on-screen keyboards. These solutions, however range from
nearly unusable. I understand that the Nokia Internet
Tablets are designed to be web surfers and media players, and are not
intended for heavy text entry, but even entering a URL can be
My needs do, however call for some text entry. What
I really want is a highly portable, inexpensive device that can do
everything the Nokia Tablets do,
but also is a laptop replacement. I need access to a UNIX command line
for things like ssh, as well as something I can use to produce the
content for linuxslate.com, like I am doing right now.
that the 770 does provide (unsupported) USB host mode, I figured that
should be some way to add a keyboard. After
reading some info on Internet Tablet Talk (Link
I was able to wire up a fairly simple solution to add a keyboard to my
770. It was a solution, but it was rather awkward, and
impeded the mobility of the 770. There had to be a better
The Nokia 770 does not support USB host mode as shipped by
Please see disclaimer below
and links below
The Nokia 770
does not provide power for peripherals, as USB normally does.
fact, it actually requires an external source of a regulated 5
volts. A simple solution was to literally bolt a small USB
a USB battery pack. The USB battery pack provides a regulated
volts from 4 AA batteries. This was wired into the USB hub,
the hub was modified so that the +5 powered not only the downstream
(Peripheral) connections, but also the upstream port. Lastly,
cable on the upstream port was replaced with one that had a mini-USB
plug that fits
First Solution used a Battery powered hub to allow standard USB
such as a keyboard, to be used with the Nokia 770.
This arrangement did allow USB keyboards to be used with the Nokia 770,
but it required quite a bit of setup each time it was to be
The fact that the USB
connector is on the bottom of the 770 made it difficult to prop up,
even with the "stand" that is included with the 770. It was
rather bulky. The USB hub was mounted on top of the battery
making it rather a large lump in a backpack or carry case.
Making the 770 a
For use with the above, I purchased an even smaller USB
This keyboard is not much larger than the 770 itself. Holding
770 above the little USB keyboard suggested a tiny laptop.
I really make something that turned the 770 into a sub-subnotebook?
To be practical, It had to meet several requirements:
- The keyboard, while small, is wider than the
completed device could be no wider or deeper than the keyboard.
- The completed, folded device should be as close to the
of just the keyboard and the 770 as possible.
770 must not be physically modified in any way, and much
still be quickly usable on it's own.
What I needed to build was basically a dock. It had to hold
770 securely, contain the batteries and USB hub as above, but be be
small enough to satisfy the size requirements mentioned above.
The basic structure is made from marine polymer (Such as that sold
under the tradename StarBoard). It is strong, relatively
and easy to machine. Several features had to be machined into
chassis. Most of it was done using a Dremmel tool with the
Dremmel router attachment. Here is a
list of the main features of the polymer chassis:
- The place for the 770
to slide in - This was the most difficult. I initially routed
an area carefully measured to be smaller than the 770. I then
used a ball shaped grinding bit to make the curved side
The space for the bottom of the 770 and the connector panel was largely
cut by trial and error. I finished off with a file and hand
sanding to get the 770 to fit just right. The marine polymer
almost a slippery feel that makes the 770 slide in very nicely, yet the
770 will not fall out even with a good shake.
speaking, the "wells" for
the batteries, power converter, and the USB hub were much easier to
cut. Another couple of cuts were made in the top to allow a
simple slide switch to be recessed.
approx 1/16 inch is removed over the batteries, power
converter, and hub to allow for a cover.
side holes were cut for the USB connectors on the hub.
- Channels are cut for the power wires and the USB
cable. The latter required a slot that is later filled with
- A slot is cut on the back for the
stand, and few finishing
touches are added such as beveling the edges, and drilling a small hole
front, just under the 770. The hole goes through to the area
under the 770's connector panel. This is to allow sound to
the 770's microphone.
There is a clear cover over the batteries and electronics
that is cut
from the top cover of a CD jewel case. The bottom of the
allow the cable from the keyboard to pass through. Some extra
room must be allowed in both the cover and the cable well so that the
cable is not pinched when the unit is closed.
The Nokia 770 Keyboard Dock's main component is a 4 port
travel router. Before it had the misfortune of meeting me, it
looked like this:
I removed the case, the upstream cable, the power jack (not
seen), and the top (right most) USB connector. That first
going to be for the keyboard. By using the top one, the
ports are available for peripherals, and are lower on the side of the
device. This helps to prevent connected cables and devices
tending to pull the unit over, and leaves room for the stand. (See side
As I mentioned the 770 does not supply power to the hub. In
it needs to be powered by the hub. This means 2
I need a source of 5 volts, and 2) I need to modify the hub
to send the power back upstream to the (770) host. The latter
accomplished by finding the
diode, and replacing it with a jumper. What do I mean by the
All of these devices have a diode that allows power to flow from the
host or an external source of power to the peripherals while preventing
flowing upstream to the host. But in our case, we want
to flow upstream. Using a DVM, and a magnifying glass it is
to find the
is circled in the
OK. Fine. The hub will now power the
plugged into the other 3 USB connectors, and the 770 -- but where does
the power come from? Well, we could use 4 batteries, and
it down to 5 volts, but given the size requirements previously
mentioned, there simply is not room for even "AAA" batteries - at least
not without some weird arrangement. There's plenty
of room for 2 "AA" batteries, though, and fortunately there are lots
of things that will efficiently step the 3 volts from 2 "AA" cells up
to a regulated 5 volts. At first, I tried the circuit board
of an iPod Shuffle (original) battery extender. This device
designed to run the iPod Shuffle from 2 "AAA" batteries:
Either it did not survive
or it will not work without talking to the iPod. I gave up
tried something else:
This device is intended to
USB cellphones from 2 "AA" batteries. If it is for phones
charge via USB, it must put out 5 volts right? Well sort
of. Since it is intended as a battery charger, it attempts to
some sort of current detection. This causes some problems,
(See the Usability and Issues section.) The circuit board is
and can be seen just under the
batteries in the pictures of the completed device. 2 wires carry the 5
volts to the USB hub.
Note of Trivia: guess what the USB hub does with the 5 volts we send
it? It regulates it down to 3.3 volts! Don't worry, our effort was not
in vien. We need the 5 volts for the 770 and for our USB peripherals.
With the hub powered, all we need to do is wire it to the
Totally by accident, it was my original Nokia USB cable that gave its
for this part of the
project, as did a Belkin car charger for Nokia N series
Most of the molding is carefully cut away from the plugs, and the
remaining cable is cut to length. The
connectors are glued into the bottom of the dock, using the 770
itself to get them positioned just right. The 770 was
with some waxpaper. I just used hot glue, but I would really
The power connector is simply wired to the left size were I put a
standard coaxial power jack (not shown here). The power jack
the one removed
from the USB hub circuit board. It seemed almost exactly the same size
as the larger, older Nokia charger jacks. Standard Nokia
fit fine, until I tried a 3rd party Nokia charger. It seems
have broken the connector, so I will replace it the next time I find a
dead Nokia cellphone. I wanted the older, larger Nokia
since I have lots of those chargers laying about. Another
cool idea would be to use the insides of a Nokia compatible USB charger
cable. That, wired to the power connector, and a female mini
connector on the side, would make your 770 chargable from
Readily available chargers for Motorola cellphones (Such as RAZR and
MING series), as well as BlackBerry would work too.
Nokia phones seem to complain if a power connector is
then no power is applied. The 770 seems not to.
I did not include an audio connector at this time. The 770
detects an audio cable being connected and changes certain audio
settings. This could
certainally be overridden in software, but Nokia is still not
particulary forthcomming about the innards of
thier low-level audio drivers. Certainally the info is out
but I opted to just skip audio for now. Headsets or
cannot be used when the 770 is in this dock.
Lastly, the keyboard is dissasembled, and the wire is made to exit from
the top as seen at the right side of the above picture. It
cut short, and hard wired into port 1 of the USB hub. Note
the cable exits parrallel to the hinge line. This allows the
cable to twist, rather than bend, as the unit is opened and
closed. It also prevents the stress on the cable from being
concentrated in any one small spot. The cable actually pushes
bit toward the hub when the unit is closed.
few things are added for finishing touches. The
following photo shows the hinges. A little glue adds strength,
especially on the keyboard side. Also shown is the stand, and
magnet near the center to keep it closed. Yes, the stand
made from a coat hanger.
Another magnet, and a screw
inserted into the keyboard is used to keep
the whole thing latched closed.
A cover for the batteries and the electronics is cut from the cover of
a CD jewel case. (hard to see since it is clear).
Here's a side view showing the stand, and the USB connectors.
I was going to paint the device black. It would look a lot
professional. I have not done this yet for 2
1) I would have to take the whole thing apart again, and 2)
paints will not stick to StarBoard. It is a little like
USB Host mode
To make anything like this work, the 770 has to be put into USB host
mode. This can be done using the flasher program.
on Internet Tablet Talk. Once in host mode,
can be put back into peripheral mode temporarily with a command issued
as root. It can then be removed from the Keyboard Dock and
as a card reader just like it worked originally. A small
can be written to make this easier.
Once in host mode, the arrangement described here works, but not very
well. The 770 is designed as a tablet, and most keyboard
support has been removed from the OS. Problems include
and keyboard working in some apps, and not others.
Bluetooth keyboards can be
installed, and this fixes nearly all the problems of keyboard
support. Get the package here.
big thanks to the folks that worked on this at
made my project work.
This is very definitely a prototype, and as such it has some
issues. The bottom line is that it is actually very usable,
in my opinion makes the 770 a much more compelling device.
issues below are listed in order of significance:
- The Power converter made from the Energizer phone
charger is just
that, a charger, not a power supply. It seems to be
sense current, and sometimes does not work right when first turned
on. The solution would be to use
something better suited to this purpose for the power
One such example is the Minty Boost.
I plan to order the kit, and replace the Energizer charger
There should be no problem fitting the Minty Boost in the same space.
- There is no automount function in Maemo. Volumes on
have mount points manually created for them, and be manually mounted
and unmounted. Softlinks can be used to make the volumes
in the Filemanager. Devices with multiple volumes (such as the
memory, and the card on my phone, or a multicard reader) take even more
effort to mount.
- I did not make a hole/slot for
the 770's stylus. If you
forget to remove the stylus, you have to remove the 770 to get
it. If you have volumes on USB devices mounted, you have to
unmount them first, or bad things can happen. My temporary
workaround is to have a stylus pen handy.
- I am
not sure if this one is a feature or a bug. The
Energizer phone charger has 2 bright blue LEDs that
flash when operating. A little "bling" is OK, and what
product these days does not contain excess blue LEDs? It
cool, but they are rather bright, and somewhat annoying when you are
trying to look at the screen. Wire cutters would take care of
LEDs very quickly. Using a semi-opaque cover for the
would fix this too.
- The Keyboard Dock with the
770 installed is a bit heavy.
Using lithium batteries
helps, and I do not think this would be a problem if it was made out of
something lighter than the marine polymer.
- Text entry on the Nokia 770 is no longer a
little keyboard is small, but considering that, it is very nice to type
on. Some of this article was typed/edited using the Keyboard Dock.
- Navigating is also facilitated by the Keyboard
usual Cut, Copy and Paste keys work, and the F4 key opens an app's
Hildon menu. The menus can be navigated with the arrow
keys. This works in the Browser/Bookmarks short cut icon too,
the PG UP and PG DOWN keys let you get a round the list faster than you
ever could before. F6 is equivalent to the full screen key on
top of the 770, and F7 and F8 zoom in some apps.
closed device, with the 770 in it, is a very nice size to
carry. It even still fits in larger (OK, really large)
pockets. It is still
much more portable than most UMPC's.
Given that the keyboard is larger than the 770, we have room for more
electronics next to the 770. Even with my limited
resources, I could have fit more in that space. Here's some
the ideas I had:
- An SD card reader. Preferably
SDHC. I have seen nice
small ones included with 4G SDHC cards. I wish I had included this in
the original design. I would happily sacrifice another USB port to
connect it too.
- I already mentioned
USB charging. How about if we extend
that to the power for the USB hub as well. USB or not,
one power connection should charge both the 770 and the Keyboard
- We could get even wilder -- How
about a mobile phone? The
phone's battery could power the hub, and we would always have our
GPRS/EDGE/Whatever connection ready to go. And with a
headset, you could even take a call.
bling is always an option too: Keyboard light?
I may pursue some or all of the possible following options
- I am going to see what it would cost
to have a small quantity of
the chassis made (molded) out of a more conventional
small production run is not beyond the realm of possibility.
- If you really, really have more money than you know what to
with, talk to me about having a pair of custom titanium ones made for
both of us.
- I may purchase a N800,
and see if/how I could do the same for the
N800. This would be made even more likely with some
"encouragement" from Nokia.
- I could also sell off
the idea. A note to any company that
sees this and plans on putting something like it into
I built it and showed the world first. Do the right
Talk to me. Send gadgets, Money, Discount Codes, etc., and
send you a letter granting
you all rights.
- Alternatively, you could simply
If I can do this in my
garage and laundry room (really), imagine what I could do with the
resources of your company!
I'll finish off with a couple more shots. I really
to include a screen shot of a 300G or so partition showing in the 770's
Filemanager. I have a USB Harddrive case, but at the moment
drive to put in it.
Thanks for your interest. Please discuss this article on the Linuxslate.com Forums
side, showing |
the charger connection.
My Motorola A780 |
Mobile Phone. The phone's filesystem
is displayed in the 770's Filemanager, and the Keyboard
Dock is actually charging the phone.
THIS DOCUMENT IS
PROVIDED BY THE AUTHOR "AS IS". IN
SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
ARISING IN ANY WAY OUT OF THE USE
OF THIS DOCUMENT, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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