User talk:Technil

From Openmoko

Jump to: navigation, search

Hey there. I probably won't have too much to say until I get the phone in ?? late April ?? sometime.. I have interest in working on:

- A cycle computer using GPS. Here is some info about power usage of the GPS:

Excerpted from "GPS time synch" thread on Community Digest

>> Based on ballpark estimates from other similar devices, it's probably >> around 70mW. >> This will really hurt if you keep it on all the time, fortunately, for >> most applications, you probably don't need to. >> If it works at 2s on, 30s off, as seems likely, this alone drains >> 1/30th of the battery per day, which isn't bad. Especially as you can >> probably back off a little if the phone has been stationary for >> several minutes. >> >> Does GPS work well in such a mode? I seem to remember from various >> handheld units that it can take quite a while (minutes) to sync up to >> a given satellite. (For all I know, you *can* operate this way, I'm >> completely clueless on the subject.)

70mW.. Here is the Neo1973 Battery info. For the sampling needed to get accurate speeds distance etc.. I don't think using AGPS and sleeping the GPS intermittently will be feasible.. so we need to know how long we can use the GPS continuously and not cripple the phone with power consumption. A dyanmo or supplemantary power source on the bike is another option but would need a regulator and dock of some sort.

The Battery is a Li-Ion 3.7V at 1200mAh or roughly 4.4 Wh. If we only let GPS use 1/4 of the battery power, that gives us 1.1Wh or 0.3 Ah at 3.7V. At 0.070 W (the "guess" on the power draw for the GPS) the current draw indicates that the GPS should work for a little bit less than 16 Hours.. Plenty even for two days of extended touring. I'm guessing this would involve probably turning off the backlight, powering down BT and cellular radios and the like, otherwise the radios and screen will drain the battery long before we can keep the device on for 16 hours.

- A high quality multi-purpose calculator. maybe Qalculate? it is GTK+ 2.4 needs scrollkeeper, libglade 2, as well as a build of libqalculate. Looks like OE has libglade and scrollkeeper, and Open Moko is GTK. So I guess I should get my OE environment all set up and do a test build. this thread on GPE maybe of importance looks like a problem with libm. This may be of use.. toolchain stuff text input might be slow, but probably no slower than a graphing calculator.

- Messing around with speex on SIP / IAX clients. Lowly GPRS... :P

--xkr47 10:56, 27 March 2007 (CEST) Thx for the gprs class info on Neo1973 Hardware. :) But one more to go.. Do you know the GPRS capability class also? It has been guessed on IRC that it would be GPRS Class B, i.e. no grps traffic while a voice call is active.. If this is true, do you know whether you can still use GPRS when someone is calling you, but before answering the phone? It could be nice to use in countries where there are cheap MSISDN <-> owner mapping services online, it could be used to (automatically or by buttonpress) look up who's calling if the number is not previously known before deciding whether to answer :)

Personal tools