Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

also a single layer of cover(transparent Poly-pack or lamination) and the device is splash-resistant & still 100% usable.. :)


good point :)
but i guess it they are mostly located on main body..

plus metal should increase there efficiency instead of decreasing it..

i guess- if it does interfere that section could be left plastic.. or the reception antennas could be shifted(soldered + extended) to camera hole(larger backcover) since its useless till now and not visible directly, and its material could be changed to whatever increase th reception..
also whatever design we are gonna get a big metal kickstand it could also do the purpose :)

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

Thanks a lot for Your kind words and feedback! BTW, for everyone who likes to support this project, please consider pre-ordering. Of course, I can't guarantee when exactly it will be available, but as a thank-You for monetary supporting this (which already gave a nice boost on project's speed, as two nice guys pre ordered full body replacement, and another nice Maemo user ordered backcover), You'll be able to provide custom logo/extengraved on backcover +, of course, being sure to be amongst first few that receive final body/backcover :)

Probably won't happen, as it would require complicated tricks or making device wider/longer. Aim of this project isn't to transform N900 into tablet-sized thing with 3.5'' screen - for most people, additional thickness is less of a problem, than a longer/wider device. Also, there is always a possibility to order flat backcover.

Of course, as I've answered to Huz, if someone prepare designs (applicable to linuxcnc) and cover costs, I'll gladly make them on my CNC for those willing to get such different kind of things.

Full sized SD card are much less expensive - especially, at earlier stage - comes first when new capacity is introduced, offer better speeds, live through more cycles, etc... Dual card setup is not possible, it doesn't work that way. You would need 2nd SD interface on N900 itself.

Flat cells that *really* offer advertised capacity are quite hard to get and much more expensive. We're talking about real capacity, not what is put on label. See battery thread for more details.

Converted to 5V is a no-go - losses in efficiency + why the hell would we want that? + if someone really need it for any reason, custom converted can be plugged to batteries itself, even before protecting PCB (again see battery thread and dr_frost_dk mods to add plug connected directly to cells)

Even putting aside fact that it would be completely incompatible with N900's battery interface/charging chip/ etc (= not possible/feasible), it's also not true. You need 3 NiMH to get average voltage of single LiIon, so 3 2500 mAh NimH's would give You *only* 2500 mAh @ 3.6V. Of course I'm putting aside "plentora" of other problems. +, NiMH's are hurt by not going through full charging cycle, ages much quicker, etc, etc... LiIon's in mobile world is actually very reasonable.

Not going to happen - results would be poor without properly considering optic's characteristic on given distance from lens, and I'm no optic's engineer.

It was asked before - of course, it would block (shield from) all signals (including gsm), if done wrong way. Fortunately, we will manage to do it proper way, without loss of signal quality or even boosting it ;)

...and would heat like hell, due to insulating, air-tight layer ;) I would be afraid to use it with anything more than 500 mhz, if encapsulated like that.

/Estel

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

Hello

The 18650 is a great idea. Could the layer currently holding the battery and adding several mm be removed to help the 18650 fit? Then, while redesigning the backcover, 2 or 3 of them should fit without adding thickness to the mugen style cover.

IIRC, the idea is to make the N900 "long term" ie robust and less dependant on stuff than can only be purchased for a month on aliexpress like scuds, or openpandora batteries.

18650 wide availability is also a great plus -I remember "repairing" vaio batteries with a stack of 18650 purchased from ebay in 2004 or 2005.

IMHO there might be n900 parts long after openpandora becomes a rarity - if only because much more n900 where sold worldwide. And 18650 will certainly be available after other n900 parts start to fail (flash?) :-)

So going with the standard 18650 seems the way to go - but only if it doesn't cause Estel too much trouble or delays in the backcover redesign.

Any news about the barrel connector??

Considering the issues with the 5v/GND pins also lacking protective circuitry, this leaves only 3 options :
- adding a minimalistic protection, like a fuse, and hooking into them (someone in EE could help!) - the easiest solution
- using the battery pads with an external charging circuit like the one selling for $4, which will confuse the charging chip
- 4 wires lead, that one has to solder into the miniusb port, with something like the optocoupler hack. This might be complicated, but is
the safest route.

BTW charging only occurs when D+/D- are shorted. Could shorting them *while* using the external circuit help the charging circuit? (I don't know about it, but it won't help if it measures charging current during charge) Could it the charging circuit be forcefed information in the software space, when triggers such as D+/D- short are detected??

Guylhem

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

That's what I have been waiting for ... amazing ... maybe You could try kickstarter to raise the funds for the prototypes ... and let the community know ... I definitely believe You should make a standard back cover as well as one that would accomodate 2 batteries. the mounts and etc should be an extra option.

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

+1 on the standard backcover using standard batteries. I won't use it, but it could be usefull for some people.

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

How about the N810 (E52) battery in conjuction with the original one? It's bigger and it seems to fit nicely in the bigger cover.

The default one is 1500mAh just like the SCUD, but the SCUD BP-4L claims 1750mAh (don't know if that is true but assuming previous experience it just may)

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

That's exactly what I though about :) It's also primary reason why it's going to be available only for body replacement, and not for "backcover only" - I would love to provide it for back's too, but it seems, that without changes in body itself, it's just not feasible.

Considering the issues with the 5v/GND pins also lacking protective circuitry, this leaves only 3 options :
- adding a minimalistic protection, like a fuse, and hooking into them (someone in EE could help!) - the easiest solution
- using the battery pads with an external charging circuit like the one selling for $4, which will confuse the charging chip
- 4 wires lead, that one has to solder into the miniusb port, with something like the optocoupler hack. This might be complicated, but is
the safest route.[/quote]

4th option is to re-create lacking protective elements *before* pins, which, via initial consultations with specialists (joerg_rw) seems possible/feasible. Still can't promise anything, but will try.

Also would like to know, if it's possible to software'ishly "cheat" device, that wall charger is connected, without shorting pins. I would be useful for various purposes.

Even if not, and *if* (still not sure) it turns out to be feasible to use testpads, I would probably just add 2nd USB port - of course, it wouldn't allow to use 2 usb peripherals at the same time (via hostmode), but would allow to charge N900 with any charger/usb cable, and would also take care of pins shorting (wall chargers have this shorted internally or inside plug).

As for barrel connector, it's probably going to make it into final design - 90%, I would say. Even if testpads solution would fail, I can just leave it ready to be modded as per dr_frost_dk's instruction. Of course, it would be included *only* in "bigger" backcover, so people waiting for lite, flat one without much addons, don't need to worry.

No way, paralleling 2 batteries with different capacity won't bring any benefits (runtime = runtime provided by lower capacity one), and would definitely bring problems. Paralleled batteries absolutely *must* be of same type, chemistry, capacity etc = in practice it means same manufacturer and similar/same age.

I think that fund-rising via pre-orders is better solution - after all, it's niche project aimed @ our Community, and Community know about it already via this thread, IRC, etc. + kickstarter "steals" too much, 5x as much as "goddamn paypal" ;) Everyone willing to support is really encouraged to do pre-order. BTW, thanks for kind words.

/Estel

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

Thanks for reply. A couple responses:

1) OK, I understand about not being able to have dual slots, oh well. Right now full sized SDXC is not that much cheaper than micro, at 64gb ($75 for micro, $55 for full size, at adorama.com). 32gb micro is just $20-25 at newegg.com. 128gb micro won't exist for a while, 128gb full size about $155 (adorama.com), I have to expect 256gb full size will come pretty soon. So full size is preferable but micro is definitely acceptable in my opinion.

2) Re flat batteries, the idea is to use decent ones intended as components ( http://www.sparkfun.com/products/8483 , http://powerstream.com/li-pol.htm ), not some mislabelled phone battery. They are standard sizes and shouldn't become unavailable. I don't mean use a custom pack from some consumer device. For putting two in the same plane, just pick sizes that fit the case, they don't have to be BL-4J's. I've always heard lithiums in parallel work very well, for both usage and charging, even if capacity is unequal. For example, the Cowon X5L audio player uses two lipo cells of different sizes.

3) Lipo seems to be safer than li ion (scary 18650 explosion pics: http://www.candlepowerforums.com/vb/...ead.php?262234 ). Ouch. And I think supplies of batteries for currently popular phones or digicams aren't likely to dry up.

4) Lens mounting thing: just a threaded hole in front of the camera is fine. Exact distance from lens isn't critical, as the camera's focusing mechanism does the right thing. People do this all the time with digicam to binocular adapters and so forth. I haven't done it with a phone but have done it with digicams. There are all kinds of iphone lens accessories at dealextreme, this is the same idea.

5) NiMH works great, those problems aren't nearly as bad as you describe, and it's easy to replace them if they go bad. Plus in a pinch you can use regular AA alkalines, very useful. So I still would really like an option like this, at least as an add-on. (It would be enough to just have some tapped mounting holes in the case, to attach a battery pack or other accessory to).

6) If you really do use 18650's then I guess you could fit 2 or 3 of them, very high capacity. Maybe the best approach is just have a single battery, thin case, with mounting holes for an add-on pack. The add-on pack would be pretty simple so there could be several sizes (2x18650, 2x BL-4J stacked, 3x AAA, etc) or fancier versions could have their own charge circuits (5V input). The packs could probably be 3D printed plastic.

Note that the voltage of the Nokia 2mm charger is somewhat higher than 5V, as you're probably aware.

One other idea: a powered USB host port and microhub (using existing USB2go) would really be awesome, if feasible. Then maybe there could be an internal space for a second microsdhc card on one of those tiny flat USB adapters.

PS, yes I can send $50 for pre-order of back cover, let's see how that goes before doing whole case.

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

I am going to make a 2x 3000mAh battery just for the fun of it and to see runtime with such a setup, this will be with 2x 18650 Ultrafire 3000mAh and as i can see from tests they come in at 2800mAh+ so that's ok, and the price... from ebay 2x costs 7 Pounds shipped

http://www.ebay.co.uk/itm/2510527421...ht_1432wt_1202

Re: [Pre-Pre-Pre Announce]Black Aluminium replacement body & backcover for N900
 

Thanks, but this sounds more like announcement for battery thread. i know I started it there, but, can we move to appropriate place with further battery-talking?

/Estel