Re: Jolla Solar Half prototype
 

The value depends on which scale the multimeter is. For example my multimeter has mA and µA and A. There's 1000 mA in one A etc. (see: http://www.adafruit.com/index.php?ma...08wire_LRG.jpg This is very basic stuff :)

Re: Jolla Solar Half prototype
 

Thanks skvark. I found my skytronic multimeter and put a fresh battery in!

Right new figures, which show much more promise! I set the multimeter to 200mA setting and showed the panel the light, the reading shot off the scale, leaving a number 1 on the left side of the meter screen, this represents that it went past the given rate!

https://fbcdn-sphotos-a-a.akamaihd.n...02687288_n.jpg
https://fbcdn-sphotos-g-a.akamaihd.n...50739175_o.jpg

I thought i'd see what voltage the panel is outputting. I read this as 5.7v or perhaps I'm a wally!, am I reading this right?, I believe I am.

So, evidently, my panel is outputting nicely. Based on a figure of 200mA, surely I can assume now, that is is sufficient to charge the phone?, none of this really tallies with the figures CSD Tool is giving! (because of my lack of knowledge I suppose!) :D

By the way, how is your panel connected to your pogo pins?

Re: Jolla Solar Half prototype
 

@Markkyboy, what are you using as a load?

You cannot just put your ammeter across the voltage source and get a meaningful reading, heh :D:D:D

Re: Jolla Solar Half prototype
 

Hi juiceme,
yep, as you have guessed, I don't really know what I'm doing! :D
I'm crap at all this, but keen to learn!
No load on the panel, just a 20 watt halogen lamp at 40mm distance.
I need to get it back on the phone and test again, but as I have clearly displayed, its all a lot of guess work! :)
Feel free to rib me all the way, I gotta learn somehow! ;)

Re: Jolla Solar Half prototype
 

First, read this: http://learn.adafruit.com/multimeters/overview

It's a very nice tutorial covering a lot of stuff how to use a multimeter.

The voltage value seems to be right.

About current sensing.. you have to get the current to flow trough the multimeter. Basically the multimeter has to be connected between the phone and the panel.

I have just two wires soldered/glued to the backside of the panel. They are positioned so that they touch the pogo pins when TOH is in place. I'm going to change the wires to copper tape later because they are too thick and prevent TOH to lock fully from the other side.

Re: Jolla Solar Half prototype
 

http://learn.adafruit.com/multimeters/overview"]http://learn.adafruit.com/multimeters/overview[/URL]

It's a very nice tutorial covering a lot of stuff how to use a multimeter.

Thanks for this, page saved/pdf downloaded. :)

Re: Jolla Solar Half prototype
 

WYSIPS google it.

Re: Jolla Solar Half prototype
 

Yesterday i have assembled my solar other half using those flexible solar panels (link posted earlier in the thread).

All seems to be working except that the phone is not charging :mad:

I think the problem might be that the panels are not delivering enough energy and voltage drops too much so that the phone stops charging from the other half.

I used multimeter and on unattached TOH i can see 6V. But once i attach it drops to 0.6V

I also tried:

# cat /sys/devices/platform/msm_ssbi.0/pm8038-core/pm8xxx-adc/dcin
Result:37554 Raw:24767

Quite unexpectedly the "Result" value raises as in darkness...

Any other ideas what might be wrong?

Re: Jolla Solar Half prototype
 

That 3,75 V is too low. Could you measure current with multimeter? Also double check connections.Those copper stripes seem to be very close to each other.

Re: Jolla Solar Half prototype
 

Hi,
oki, i will try to check current but need to lead the wires out of the case, so it might take a few days until i get to it...

The copper stripes are close, but as far as i could check they seem to be ok. There is 6V on them when measured with multimeter and when i placed a piece of plasticine the pogo pins made two holes on the right places...

Re: Jolla Solar Half prototype
 

You need an energy harvester ic in order to make this work.

Have a look here https://www.youtube.com/watch?v=lrELRVFEx_s

Re: Jolla Solar Half prototype
 

I would personally use LTC3105
http://www.linear.com/product/LTC3105

Re: Jolla Solar Half prototype
 

Hi,
it seems that my first version had swapped + and - although i have checked several times i did it wrong :confused:

Yesterday i redid the whole thing from scratch again. This time i used plasticine for precise copper stripes position and verified with 4.5V battery that charging works - and it worked.

After attaching solar panels it showed no activity under lamp, but later on direct sun the phone vibrated and displayed charging dialog + the white led was shining.

This is ok, but i havent seen that battery charge raised. In idle my jolla normally eats ~7mA, the panels should deliver 25mA so the charging current should be ~18mA. But i wonder if the phone is really idle while charging. And i wonder how to measure it...

Thanks for the link - interesting, but i wonder if it will fit somewhere under the cover...

Re: Jolla Solar Half prototype
 

To get 1% more charge (21 mAh), you have to keep the panels in direct sunlight for over an hour.
18 mA is very very slow charging rate.

Re: Jolla Solar Half prototype
 

Did you mean 21 mAh :)?

Indeed. Assuming 6V (being generous here, the real voltage must be much lower), it means only 150 mW (6V x 25 mA). That's about an order of magnitude less than what I would expect. Either the light level was very low or the panels are too small (covering less than 10% of the back space), particularly poor quality or damaged by the previous experiment with reversed polarity.

Re: Jolla Solar Half prototype
 

Yeah :)

@psonek, could you look what the phone says about the voltage now that the polarity is right (cat /sys/devices/platform/msm_ssbi.0/pm8038-core/pm8xxx-adc/dcin)?

Re: Jolla Solar Half prototype
 

I'm a bit afraid the whole thing will become hot. When I put my WakaWaka in the sun, it will be hot in an hour. Make the solar panel or the OH detachable so the phone can get some shade? :cool:

Re: Jolla Solar Half prototype
 

ehhh

http://www.quickmeme.com/img/e5/e564...df619d4b84.jpg

isn't this the case for every solar oh??

either
-accept it (join the sunny side)
or
-make a detachable third-half with solar panel and battery

Re: Jolla Solar Half prototype
 

[root@jolla nemo]# cat /sys/devices/platform/msm_ssbi.0/pm8038-core/pm8xxx-adc/dcin
Result:4314054 Raw:32057
[root@jolla nemo]# cat /sys/devices/platform/msm_ssbi.0/pm8038-core/pm8xxx-adc/dcin
Result:4514790 Raw:32399

Mostly the values seem to be between 4.3V and 4.5V

Re: Jolla Solar Half prototype
 

Hi,
after a few days i still have not seen the battery being really charged with my solar toh.

I wonder where is problem. Battery status is "Charging", but current_now is never negative. Even more interestingly while charging it seems to consume more power.

In dark on wifi ssh i get values like this:

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
2595

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
8415

Under lamp while solar charging:

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
10618

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
11876

Maybe while charging the phone wont enter deep sleep?

Re: Jolla Solar Half prototype
 

Yep, it stays active when charging.

Re: Jolla Solar Half prototype
 

You need better solar panel(s). For example my panel gives out 4x more juice per hour.

Re: Jolla Solar Half prototype
 

It seems that my theory is right verified by simple test. First stop upowerd so that it does not blink with leds, vibra and undims screen:

killall -s STOP upowerd

Then i have simple script that blinks with red led:

[root@jolla nemo]# cat ./blink.sh
#!/bin/bash
while true
do
sleep 1
echo 0 > "/sys/class/leds/led:rgb_red/brightness"
sleep 1
echo 50 > "/sys/class/leds/led:rgb_red/brightness"
done

Run this script and put the phone in standby.

Normaly the led stops blinking soon because CPU enters idle state. While powered by solar TOH it keeps blinking which indicates that CPU is not idle.

Does this make sense? I wonder what to do so that the processor goes idle. Otherwise solar charges will be quite ineffective because ~30mA is wasted on CPU.

Re: Jolla Solar Half prototype
 

Oki, some more debugging:

cat /proc/wakelocks | sort > w1.txt ; sleep 5; cat /proc/wakelocks | sort > w2.txt ; diff -u w1.txt w2.txt | grep '+\|-'

After this command if i move jolla under lamp, the CPU wakes up and shows this interesting lines:

-"power-supply" 2097 0 11 0 1156191680 1098783785 17446964 2266241071209
-"power-supply" 218 0 0 0 187567735 165166352 9797039 2266240949161
-"power-supply" 239 0 0 0 1541130070 1139839364 44895468 2266244946246
+"power-supply" 2106 0 11 0 1169010084 1111602189 17446964 2326885012348
+"power-supply" 222 0 0 0 194434802 172033419 9797039 2326884890266
+"power-supply" 243 0 0 0 1578425861 1177104634 44895468 2326898532864

If i understad it well then CPU wont go idle because of "power-supply" wakelock. This wakelock is defined in linux kernel in power_supply_core.c The question is now how to suppress it.

Re: Jolla Solar Half prototype
 

Sure, i even ordered stronger panel, but it's also thicker and wont be as nice as these thin stripes.

I'd still consider this as bug unless there is good explanation why the CPU does not enter idle state (my previous phones didnt have problem with this). The charging rate will slow down because of this very much.

As far as i can see the only workaround could be done by recompiling kernel, but i am afraid that this is quite dangerous becase we dont have kernel sources, flasher etc..

Re: Jolla Solar Half prototype
 

Now this is guesswork, as I do not know the HW internals of the Jolla device so well, but if it follows the design of N9 at all, then the device has to be alive to monitor the battery charging process.

Some devices implement the charging all in the HW, for example the older symbian devices. On some devices the algorithms are run by SW in the main CPU.

Re: Jolla Solar Half prototype
 

When details on Jolla's TOH interface were announced, and it was speculated it could be used for solar charging and such, I always assumed one would have to implement it as solar panel + battery, with the panel slowly charging up its own battery, and then dumping that battery quickly to jolla, in order to minimize extra energy use for phone.

Re: Jolla Solar Half prototype
 

hmm... could a thin supercap utilised here? to allow fast discarge/charging cycles.
Annoying thing here will be the constant notifications charging/not charging, unless some tricks could be made. maybe need to do some lab-supply-experiments, iirc if voltage is lowered to certain level, it will say it is charging, but draws minimal current.
I imagine this is place for small micro to take care of the charge cycling, monitoring charge level of supercap and discharge to the phone.

first google result: http://www.cap-xx.com/

Re: Jolla Solar Half prototype
 

Yup, we'll have to figure out how it's done in Jolla. If it's done in SW it could be maybe improved by rtc wakeups?

Re: Jolla Solar Half prototype
 

The trick is quite simple:

killall -s STOP upowerd

it's more hack then trick, but it works :) Maybe the charging could be controlled by simple circuit on i2c pins - you could disable the charging notification before you start charging from the supercap.

Re: Jolla Solar Half prototype
 

Hi,
yesterday i hacked jolla's kernel so that CPU goes to deep sleep even while charging and got first success. I can see the phone being charged with current ~3mA (see attached screenshot). I have no idea if that will be useful for anything though :D

Now i am waiting for sunny day and more powerful solar panel...

Re: Jolla Solar Half prototype
 

Anything new?? =) This would be awesome, I need this for my looong trips haha

Re: Jolla Solar Half prototype
 

I need this for my bike trip too, but the bigger solar panel havent arrived after month of waiting :(

For now i am experimenting with crank charger from evolveo, but IMO there is same problem as with solar charger - the CPU does not go in standby while USB is plugged so the charging current is rather low and i was unable to charge single % of battery until now...

We should either somehow fix Jolla or it would be needed to charge some external battery/capacitor first and use it to provide high current.

Re: Jolla Solar Half prototype
 

How many hours can take to charge the battery of the Jolla using our first proto of the solar charger?
And maybe could be possible some hack to make the CPU stand by and charge faster...

Re: Jolla Solar Half prototype
 

With my proto it would take propably ~15 hours in the best-case scenario but in reality it will never happen.

Re: Jolla Solar Half prototype
 

You, my friend, have invented phone with infinite standby time :)

BTW, would you happen to have that kernel hack in a git tree somewhere?

Re: Jolla Solar Half prototype
 

I have it on my computer at home. I can dig it up and put online in the evening. But even with this hack it's not usable, see:

https://together.jolla.com/question/...-toh-charging/

Re: Jolla Solar Half prototype
 

bump

had some interesting results with a panel, but still a lot of room for improvement in standby current and deep sleep while charging.

i would love to experiment with that deep sleep kernel hack, please dig that up!

Re: Jolla Solar Half prototype
 

Ok, here it is:

http://activationrecord.net/radekp/p...akelocks.patch

How to build? I have dumped jolla's boot partition, unpacked it, assembled with my custom kernel and flashed to recovery partition. It can be then booted using POWER+VOLUME buttons. Maybe i could rebuild and upload the partition img for latest jolla release.

How to test? Make simple script which blinks with led. When CPU is alive it blinks, when CPU goes to suspend it stops blinking.

On jolla stock kernel:

- blinks during charging -> CPU awake
- stops blinking when not charging -> CPU suspended

On patched kernel:

- always stops blinking always -> CPU suspended

Re: Jolla Solar Half prototype
 

Are you planning to release flashable image for the latest update ? :)