OCPN for Android Proof of Concept and Teaser....

[seandepagnier]

Originally Posted by RhythmDoctor

As pointed out elsewhere, ad hoc WiFi networks hosted on your PC are problematic, especially with Android devices. Many WiFi routers use A LOT of energy (big power bricks), but on a sailboat you don't need huge transmission power. Since you don't need huge transmission power, there are lower-power routers available. This is the one I've purchased - it runs off of USB power, which by definition is <500 mA @ 5v:

What is the problem with making either the PC or android device act as an access point? This is normally what I do so all my computers can connect using dhcp and get internet through the one that is online.

You can set the transmission power and many parameters in hostapd.conf

Why would you have a separate router? extra cost and power use?

Originally Posted by barnakiel

Are we talking a mobile device?

Plain wifi uses WAY more than BT.

This is true.

What I'm getting at is the wifi devices I have use a few hundred milli watts. This is a small fraction of the total power use of any device I have seen which is powerful enough to run opencpn. Maybe on a smartphone this is too much for the small battery in it?

PS Try any device with wifi togged on/off then watch how long the battery lasts. You WILL see what I am talking about.

b.

What device? I think this applies mostly to very small devices, but it's a valid point.

[RhythmDoctor]

Originally Posted by barnakiel

...So to say, if one wants to share NMEA via the laptop (and the laptop runs an AP capable version of Windows (7, 8, etc., I think) this may be arranged. And a small netbook can be the cheapest multiplexer / router too; still, not most power efficient...

Five years ago a netbook would have been cheapest and most power efficient, and I ran one on the boat during that time.

But now, Windows8 tablets are more power efficient and can be gotten for around $200. However, you will have to check and see if the version of Win8 that they're shipping will create an ad hoc network. (You'd have to check this for a netbook also.)

As a general rule, anything that gets its power through a USB cable is going to be pretty energy efficient, since USB power specs are so thrifty. I would expect the combination of a Win8 tablet and WiFi router would be more efficient than the 19w power brick on my old netbook. And if you can run and ad hoc network off the tablet for non-Android devices (or rooted Android devices), then you're getting a lot of bang for very little energy.

When I get some spare time I'll get out my wattmeter and try to do some comparative testing on the power draw from my netbook, Win8 tablet, and ZyXel router. Then we can have real data to compare.

[RhythmDoctor]

Originally Posted by CarCode

When you will have a look at the Bluetooth 4 specs it will even use less power. But of course both sides needs a BT4 device. An example of low power BT consumption is the new SailTimer Wind Instrumentâ„¢

Gerhard

By the way, that wind instrument just launched for pre-orders this morning. I place my order. My Win8 tablet does support BT4, so I'm looking forward to displaying its output using the dashboard plugin.

[seandepagnier]

Originally Posted by RhythmDoctor

When I get some spare time I'll get out my wattmeter and try to do some comparative testing on the power draw from my netbook, Win8 tablet, and ZyXel router. Then we can have real data to compare.

Yes, and do tell us power statistics with wifi off, on with no data, and on while transferring files at max speed (and what this speed is)

[barnakiel]

Originally Posted by boat_alexandra

What is the problem with making either the PC or android device act as an access point? This is normally what I do so all my computers can connect using dhcp and get internet through the one that is online.

A PC connected to an Android device AP is what I call reverse tether. Almost all Android software I tried out was unwilling to suck in NMEA data via wifi connection set up this way. When the AP was set up on the laptop side then everything went way smoother.

And the opposite way (AP on Windows, Android connects to it) requires minimum Windows 7, preferably 8, on the PC end. Ad hoc network is not enough as Android devices (many not all) are not readily connecting to Windows ad-hoc networks.

BTW not all Android versions create AP either.

Last but not least, one still has to feed nmea into that PC up first. This can be extra trouble and cost (e.g. serial to USB cables, etc.)

As long as the App has a wifi socket for NMEA data, we are fine. And ability to use the device's built-in GPS a top priority above everything else. Why get data from elsewhere when it is already available on the Android device.

b.

[barnakiel]

Originally Posted by RhythmDoctor

Five years ago a netbook would have been cheapest and most power efficient, and I ran one on the boat during that time.

But now, Windows8 tablets are more power efficient and can be gotten for around $200. However, you will have to check and see if the version of Win8 that they're shipping will create an ad hoc network. (You'd have to check this for a netbook also.)

(...)

AP, NOT ad-hoc!

Ad-hoc is a dead alley with Android devices.

Here (EU) there is only one Windows tablet in this price range - the earliest and most ancient Acer 8 incher. This one has issues (e.g. not using its in-built GPS for OpenCPN gps source.

And, once one invests into a Win 8 (non-RT !!!) tablet, then the whole discussion expires as we can then run Win version of OpenCPN on the tablet.

BUT Win 8+ tablets ARE still expensive here - easily 3 to 4 times the cost of an Android tablet.

b.

[barnakiel]

Sample consumption:

netbook, 10 inch, wifi on: 1A (full brightness),
tablet, 7 ich, wifi on: 0.5A (as above),
wifi router run as AP: 0.5A,
wifi NMEA multiplexex/router: 0.1A, (sic!!!)

b.

[bcn]

Originally Posted by barnakiel

And, once one invests into a Win 8 (non-RT !!!) tablet, then the whole discussion expires as we can then run Win version of OpenCPN on the tablet.

BUT Win 8+ tablets ARE still expensive here - easily 3 to 4 times the cost of an Android tablet.

b.

looks like this is changing:
----------------------------------------------------
HP Stream 7 5700ng Tablet N 129€ (Tax incl.)
Windows 8.1 mit Bing 32
Intel® Atom® Z3735G
17,8 cm (7")
1 GB DDR3L SDRAM
32 GB eMMC, 1 TB OneDrive (1 Jahr kostenlos)
1 J. eingeschränkte HW-Garantie
------------------------------------------------------
HP Stream 8 5900ng Tablet 209€ (tax incl.)
Windows 8.1 mit Bing 32
Intel® Atom® Z3735G mit Intel HD-Grafikkarte (1,8 GHz, 2 MB Cache, 4 Kerne)
20,3 cm (8")
1 GB LPDDR2 SDRAM
32 GB eMMC
------------------------------------------------------

More coming....

[GrowleyMonster]

Originally Posted by barnakiel

AP, NOT ad-hoc!

Ad-hoc is a dead alley with Android devices.

Here (EU) there is only one Windows tablet in this price range - the earliest and most ancient Acer 8 incher. This one has issues (e.g. not using its in-built GPS for OpenCPN gps source.

And, once one invests into a Win 8 (non-RT !!!) tablet, then the whole discussion expires as we can then run Win version of OpenCPN on the tablet.

BUT Win 8+ tablets ARE still expensive here - easily 3 to 4 times the cost of an Android tablet.

b.

Not to mention some of us simply refuse to run Windows on principle. It really has become a horrible os.

[barnakiel]

Originally Posted by bcn

looks like this is changing:
----------------------------------------------------
HP Stream 7

(...)

A GPS-less device for navigation?

WHY?

And I hope they mean 8 where they say 8 because last time they sold RT while telling people 8.

Mobile is to use it ex wires. GPS must be on the device.

If we want wires, we can stick with a laptop. Huh?

b.

[barnakiel]

Originally Posted by GrowleyMonster

Not to mention some of us simply refuse to run Windows on principle. It really has become a horrible os.

Yes.

And not all of us can afford a Mac to use for one purpose only.

So, in my limited world, it is an Android mobile device and a Windows netbook. Inexpensive combo that does 99% of all my needs.

But I am not excluding a Win 8 tablet in the future, just the ones laying about are too darn expensive - on par with Mac things and often beyond. And when they are not, they deliver less productivity than comparable Android tablets, for more money. Zero reasons to buy.

b.

[GrowleyMonster]

Originally Posted by barnakiel

Yes.

And not all of us can afford a Mac to use for one purpose only.

So, in my limited world, it is an Android mobile device and a Windows netbook. Inexpensive combo that does 99% of all my needs.

But I am not excluding a Win 8 tablet in the future, just the ones laying about are too darn expensive - on par with Mac things and often beyond. And when they are not, they deliver less productivity than comparable Android tablets, for more money. Zero reasons to buy.

b.

Don't like Mac either. I am running Ubuntu and loving it. But my android devices have taken over most of my computing needs. Typing on a Note3 right now.

[RhythmDoctor]

Originally Posted by barnakiel

Sample consumption:

netbook, 10 inch, wifi on: 1A (full brightness),
tablet, 7 ich, wifi on: 0.5A (as above),
wifi router run as AP: 0.5A,
wifi NMEA multiplexex/router: 0.1A, (sic!!!)

b.

Amps is practically meaningless without voltage. My netbook draws about 1A also (at peak), but it's at 19v. Different brands of netbook run at 12v, 18v, and 19v. Some WiFi routers also need higher voltage.

My ZyXel and tablet run off USB power at 5v. So at a given current, it's about 1/4 the power draw of my netbook.

All that is why a Watt meter is really the way to measure these things.

Originally Posted by barnakiel

...And I hope they mean 8 where they say 8 because last time they sold RT while telling people 8...

I think you're sounding a little biased here. There's virtually nothing for sale out there that runs RT anymore. So your statement is sort of irrelevant.

Originally Posted by barnakiel

Here (EU) there is only one Windows tablet in this price range - the earliest and most ancient Acer 8 incher. This one has issues (e.g. not using its in-built GPS for OpenCPN gps source.

And, once one invests into a Win 8 (non-RT !!!) tablet, then the whole discussion expires as we can then run Win version of OpenCPN on the tablet.

BUT Win 8+ tablets ARE still expensive here - easily 3 to 4 times the cost of an Android tablet...

Have you tried GeolocationTCP software? I don't know about the Acer specifically, but all Win8 tablets have a problem with internal GPS, and GeolocationTCP fixes it for me.

And I'm sorry, I had forgotten that the topic of this thread was Android devices, so ad hoc network is not so good. That makes a low-power WiFi all the more beneficial. The one I linked can be found for $15. What kind of price did you get on your wifi NMEA multiplexex/router? The cheapest one that I could find cost 2-3 times what my Win8 tablet costs.

[seandepagnier]

I recommend running linux and using hostapd to make an access point.

[RhythmDoctor]

Originally Posted by RhythmDoctor

...When I get some spare time I'll get out my wattmeter and try to do some comparative testing on the power draw from my netbook, Win8 tablet, and ZyXel router. Then we can have real data to compare.

OK, I got the Kill-a-watt meter (Model P3) off the boat this morning and did some testing at home. All tests were done on 120v power. For devices that run off of USB power, I used an Apple 10w Power Adapter that came with an iPad. I chose this because it is very common, and generally known to be high quality. For the netbook test, I used the manufacturer-supplied power brick, which supplies up to 2A at 20v. The rectification and step-down circuitry needed to go from 120vAC to 5 or 20vDC always has some inherent inefficiency, so the power readings below may reflect higher values than if the devices were connected to a 12vDC battery system, where rectification is not needed (but step-up or step-down transformer is still needed).

Here are some readings, in the order that I did them:

  Device                                          Watts
  
  Apple 10w white cube adapter, nothing attached  0.0
  
  Miix2, off, fully charged                       0.3
  Miix2 while booting                             3.0
  Miix2 booted, full brightness                   3.0
  Miix2 booted, min. brightness                   3.0
  Miix2, sleep                                    1.2-1.4
  Miix2, airplane mode                            2.6
  Miix2, wifi off                                 2.5-2.6
  Miix2, wifi on, downloading updates             3.0
  
  ZyXEL Travel Router 100% RF power               1.3-1.5
  ZyXEL Travel Router 35% RF power                1.3-1.5
  
  MSI Wind netbook:
  
  Charger only                                    0.0-0.3
  
  With partially charged battery inserted:
  Netbook charging while off                      3.0
  Resuming from hibernation                       20.0
  Running after resume                            15.6-16.4
  
  With battery removed:
  Running - no battery                            13.1-13.7
  Running - no battery, turbo mode                13.5-13.8
  Running + BT                                    16.9-17.6
  Running + WiFi                                  18.3-18.0
  Running + BT + WiFi                             20-22

  With partically charged battery re-inserted:
  Doing Windows Update w/battery                  up to 33
  Standby w/battery charging                      30.8, decreasing w/ time to 0.3
  Running - fully charged battery                 13.1-13.7
  Updating AVG                                    16.2-16.6
  After AVG update complete                       11.7-12.1

Comments: With its complete lack of mechanical components (no fan, no hard drive), the Miix2's power draw was very stable and predictable. It was basically 3 watts. This was the same no matter what the screen brightness was set at - somewhat surprising, since the screen is SO bright. Actively downloading and installing updates did not affect this either. Some small reduction to 2.5-2.6 watts was seen with WiFi off and in airplane mode. On the boat I generally keep WiFi off.

The ZyXEL travel router sips only 1.3-1.5 watts of power. This is much less than the 7-15 watts that I've seen for household routers that run off of 120v. The ZyXEL offers the ability to turn back the RF power if its WiFi transmission. Since sailboats are small, this may be a good idea to minimize that chance of others poaching your signal, but it had no effect on power draw.

My MSI Wind netbook is showing its age. The battery is going bad, and was partially discharged when I started the test, so I removed the battery initially to eliminate that variable. Power draw fluctuated a lot, largely because the internal fan and hard drive would come on and off periodically, especially when data was being transferred. With battery charging, it would draw up to 33 watts. With battery fully charged or removed, power consumption was typically 12-20 watts, 4-7x the consumption of the tablet.

It's clear that a tablet and/or travel router would provide far better energy efficiency than the netbook running as an access point. Last summer I pretty much ditched my netbook and used the tablet with keyboard/mouse when I had to do "computer stuff" while running off of 12v. Based on power consumption, I think I'll continue this next season.