[Commotion-dev] Android stick-PCs as a potential Commotion/FreedomBox/OpenWRT platform?

Wed Apr 24 22:15:30 UTC 2013

They're available for about US$40-70 on amazon:
http://www.amazon.com/MK808-Android-Rockchip-RK3066-Cortex-A9/dp/B009OX22B4
http://www.amazon.com/Android-Smart-internet-adaptor-dongle/dp/B009F8HS4E/ref=sr_1_4?s=electronics&ie=UTF8&qid=1366841516&sr=1-4&keywords=ug802

The have much faster CPUs that are also dual core.  They include 4GB storage and have a micro-sd slot and USB.  They are also ready to go with Android and the Play Store installed.  I think they are probably a better deal than the RPi for working with wifi.  Attach an external USB wifi, and you have a two radio device.

But this is all contingent on having decent adhoc support in the radio, of course.

.hc

On Apr 24, 2013, at 6:07 PM, Dan Staples wrote:

> The Android sticks certainly do make a tempting platform for some experimentation. I wonder, however, how they compare in capability-versus-price with the Raspberry Pi. An RPi by itself costs US$35, and has ethernet, 2 usb, 512MB RAM, 700 MHz single core processor, and draws b/w 500-1000 mA @ 5 V (= 2.5-5 W if my physics degree serves me well ;) ). Attach to that a dual-antenna Atheros-based USB wifi adapter (e.g. http://www.tp-link.com/en/products/details/?model=TL-WN822N), which can potentially do multiple virtual interfaces, one in ad-hoc and the other in AP mode, and you got yourself a pretty capable gadget.
> 
> And at a recent conference, I powered some wifi-enabled, meshing RPis with simple battery packs. I've even powered them from 2 D cells with a proper voltage converter, which could potentially power a device for more than a day.
> 
> Just another idea to throw into the mix...  I think experimenting with the android sticks is a great idea.
> 
> cheers,
> Dan
> 
> 
> On 04/24/2013 05:28 PM, Paul Gardner-Stephen wrote:
>> Hi all,
>> 
>> Sorry if you have already thought about and discussed these devices, but they strike me as potentially very interesting for both communities, in addition to our own interest in them for the Serval Project.
>> 
>> We have been looking at some of the cheap Android-based stick PCs as a possible platform for Serval Mesh Extenders, such as the MK802ii and more recent MK808B.  For more about the Mesh Extenders and their long-range UHF packet radios, refer to:
>> 
>> http://developer.servalproject.org/dokuwiki/doku.php?id=content:meshhelper:main_page&#prototyping 
>> 
>> or:
>> 
>> http://servalpaul.blogspot.com/2013/02/building-serval-mesh-helper-device.html
>> 
>> and subsequent posts to that blog.
>> 
>> The newer generations of the Android stick-PCs have dual-core 1.5GHz ARM processors, 1GB of RAM and 16GB of flash, dual-antenna 802.11n Wi-Fi (although the firmware is not ideal, more on that later), USB host port, microSD slot, and HDMI out, all in a tiny thing about 80mm x 35mm x 15mm depending on the particular variant you get.  You get all that for under US$50, e.g., from geekbuying.com.
>> 
>> These typically come with a root-enabled ROM, and are very easy to flash with a complete new operating system.
>> 
>> Thus compared with many wireless routers they have much greater CPU and memory resources, and similar or lower cost.
>> 
>> What I wanted to discover what their power consumption was, because I want to run them off battery for really resilient deployments.  
>> 
>> While I was initially concerned about the power consumption, I discovered that the later generation models can perform useful services, including running Wi-Fi for about 1W:
>> 
>> http://servalpaul.blogspot.com/2013/04/comparing-energy-consumption-of.html
>> 
>> The main issues that I have identified are likely to be:
>> 
>> 1. The Wi-Fi antenna are little patch antenna, which probably don't have that great performance.  They could be replaced fairly easily though, I suspect.  On the up-side, they do have two antenna for doing clever 802.11n things.
>> 
>> 2. The Wi-Fi firmware that comes with the ROMs I have found don't include simultaneous AP and ad-hoc capability, at least as far as I can tell.  This would need investigation.  They apparently use a Broadcom 8330 based Wi-Fi chipset in at least some variants, which leads to my next point.
>> 
>> 3. The Wi-Fi chipset and design quality varies between suppliers of these, as it appears that they are all using a reference design of the RK3066 chipset, to which they add Wi-Fi.  Some use realtek or mediatek chipsets instead of broadcom.  Some implementations are better than others, e.g., some sub-optimal implementations seem to have a common ground-plane between the Wi-Fi and USB, which reduces the sensitivity of the Wi-Fi receiver. All this is both a negative and positive. On the negative side, some variants might be complete duds for our desired use-cases.  On the positive side, it might be possible to encourage one of these manufacturers to make one with, for example, an Atheros Wi-Fi chipset that is well supported by Linux, OpenWRT and Debian.  Related, I have yet to survey the complete OS image to see if there are any other closed binary blobs hiding around the place.
>> 
>> 4. There is no on-board ethernet port on the cheaper models.  This could be solved with a USB ethernet adapter, or again, encouraging one of the manufacturers to make a variant that is better optimised for our communities needs.
>> 
>> If anyone in the community is interested in working on porting OpenWRT and/or enabling simultaneous AP+ad-hoc Wi-Fi on these, we can probably arrange to provide a couple of MK808Bs to facilitate this.
>> 
>> Paul.
>> 
>> 
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> 
> -- 
> Dan Staples
> 
> Open Technology Institute
> https://commotionwireless.net
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