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Sun, 26 Oct 2008

Nokia Internet Tablet battery life

I wonder when Nokia is going to run up against the concept of "applications which are so compelling you want to run them all day long" and "A battery which cannot run all day long, and which cannot be changed out without rebooting"?

A truly useful device will have an external battery sufficient to run most peripherals and the CPU constantly all day long. Power saving is for weenies who aren't actually using the device. It will also have an internal battery sufficient for occasional use as long as you recharge daily, and enough to tide you over while you're switching external batteries.

posted at: 06:48 | path: /770 | permanent link to this entry

Mon, 05 Nov 2007

Free Chordite status

I thought I'd report on the status of my offer of two free keyboards. Curiously, I only received three keyboard requests. I meant to impose a barrier to entry, but maybe not that high a barrier!

I decided not to choose, but instead to make three keyboards. I have ordered and received the electronic parts. I've decided that while I might be able to produce keyboards from the hand photocopies the winners sent in, it's too uncertain a process. Still tinkering with the design, but I think I've settled more on a "kit" for a keyboard.

The trouble with the Chordite is that it really needs to fit your hand. And yet, as a portable device, it needs to be sturdy. Adjustable yet fixed. Malleable yet unchanging. This is not a new problem for people to have faced. Screws, nuts and bolts, glue, clay, plaster, wood, plastic, metal, and rock are all substances which can be changed and yet which are sturdy.

Hands are variable in two ways that matter: in finger length and spacing and in palm width. The chordite needs to be stretchy in both those dimensions, and yet, if you drop it, it shouldn't fall into pieces. It needs to be lightweight so that you can carry it. In order to make all this work, I think that I'll put the switches on little PC boards interconnected with 18 gauge copper wires, covered with a layer of polycapralone. The copper for stiffness, and the polycapralone for sturdiness.

I've done some testing, and an ordinary hair dryer puts out enough heat to soften a fairly thick layer of polycapralone. Once softened, the keys can be moved around, with the copper wire keeping the keys in position while the polycapralone is soft.

Once I've made the PC board with the bluetooth module at the heart of this keyboard, I'll ship these to the lucky winners. We'll see what they have to say. If it's not good, then back to the drawing board.

posted at: 21:34 | path: /770 | permanent link to this entry

Sat, 06 Oct 2007

N800 External Battery

The internal N800 battery is pretty studly, but there are contexts in which I don't want to have to swap out the battery for a spare. Have to reboot the machine to do that and if you're trying to run a program for a long time or continuously, that's not acceptable. Plus you have to notice that the battery has run low and replace it.

So, I have made myself an external battery holder. It's an "External Li-ion Battery Pack". Input is 5V, 500ma. Output is 5V, 6.8Wh. By way of comparison, the internal BP-5L battery is 1.5Wh, so this battery has four times the power. Cost me $26 bucks postpaid from CaBattery. Comes with a power adapter with a standard-size Nokia coax connector, a USB to coax connector (which can also be used to charge the battery from any USB port), and a set of coax to (whatever) adapters including an N-series coax.

I scavenged an old USB cable connector and got an N-series coaxial power adapter from a local electronics store. Cut the plastic off both of them and greatly shortened the cables, being careful to check and double-check the polarity (center positive for the coax). Both cables were marked red (postive) and black (negative) so it was no trouble.

I have a supply of polycaprolactone (capa for short) which I purchased from Shape-Lock also sold as Polymorph or Friendly Plastic. I covered the N800 and external battery with aluminum foil because the capa will stick to plastic. The cable needed to be covered with plastic, so being careful not to short out the cable to the aluminum foil, I opened two holes for either end of the cable and plugged it in.

The capa is soft like modeling clay and hardens like nylon when cool. Thin pieces cool off pretty quickly, so you don't get much work time. I wrapped the capa sheet around the back of the N800, covering the external battery and wrapping around to the front. I purposefully made the right-hand wraps thicker to hold the cable and connectors in place. The left-hand wraps are thinner, so I could bend them to fetch the N800 from its embrace.

As it turns out, I didn't use enough capa, so quickly heated up another batch and made the corner fingers and covered the battery a little better. It will stick to itself if both surfaces are reasonably warm.

I still need to cut some holes for the external battery charger and power monitor. Also need a hole to fetch out the stylus and connect the headset. Capa cuts pretty easily as long as you don't heat it up. It softens then and melts rather than cuts.

I've run it on the battery mostly idling but wifi-connected for nearly two days before the external battery ran out and I noticed the internal battery start to lose its charge. I'm sure I could have gotten a full two days out of it. I expect to get ten hours of solid use out of the combination.

UPDATE 8/20/2008: Note that the N800 and N810's power supply must be within certain limits. See Nokia's charging interface specification.

Hover for a caption or click on the thumbnail for a larger picture:
front view (Thumbnail) top botton view (Thumbnail)
coax power connector lump (Thumbnail) removing the N800 (Thumbnail)
coax power connector (Thumbnail) USB power connector (Thumbnail)
battery coax in and USB out (Thumbnail) cable (Thumbnail)

posted at: 02:14 | path: /770 | permanent link to this entry

Thu, 06 Sep 2007

Why a unibutton?

Why does the N800 have a unibutton and a hidden button on the top? The 770 had three separate buttons on the top. The left button is now in the middle on the N800. The rocker switch (press left, press right) is now split into two buttons, on left and right. The power menu button on the 770 was arguably too easy to press, so I count the hidden button on the N800 an improvement.

But to merge the two buttons into one unibutton which is practically impossible to distinguish?? Why? The only way to distinguish between the buttons is to slide your finger back and forth a few times, trying to feel the subtle slope from the left to the middle and back down on the right. Only then can you take a guess at which button your finger is on.

Going back to the 770's buttons would be an improvement. Let's hope that the N830 (or whatever) makes that change.

posted at: 04:22 | path: /770 | permanent link to this entry

Tue, 04 Sep 2007

Never use a warning

Aza Raskin writes Never Use a Warning, in which I count him as agreeing with my assessment of the Connection Manager's warnings.

posted at: 04:53 | path: /770 | permanent link to this entry

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