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 Raspberry Pi, Rm100 computer that beats iPhone4S

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aba9785
post Dec 26 2012, 11:47 PM

el aba9785
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From: Penang


QUOTE(binjai @ Dec 20 2012, 11:06 AM)
guys... any1 using the 7 port usb hub wif ac adaptor to power up your Pi? got this pic from lelong website... looks promising hehe  tongue.gif
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just got my rpi recently, didnt really got time to test it.
but that 7port hub is working fine with the rpi.
still need to test more/abuse kau kau to see if it is reliable or not brows.gif


i got a question...usually u all use the rpi for media center/nas?
aba9785
post Dec 27 2012, 12:00 AM

el aba9785
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From: Penang


QUOTE(quadcube @ Dec 26 2012, 11:56 PM)
yeap,using it as a nas currently..planing to utilize the gpio pins soon smile.gif
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so u r connecting your ext hdd to rpi, then share the drive with the whole family, correct?
so far so good?

how about BT, will rpi be able to handle BT without any issue?
aba9785
post Dec 27 2012, 08:41 AM

el aba9785
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Joined: Jun 2005
From: Penang


QUOTE(quadcube @ Dec 27 2012, 12:29 AM)
nope,not using ext hdd,don't have enough funding for one *poor* using the sd card as the hd,currently holding all my music collection..BT?bluetooth or bittorrent?
*
yup. BT as in bit torrent (assuming we use it for legitimate download laugh.gif )

hmm...so how do u transfer the files in to the SD? u r using a linux/unix/mac machine, correct?


Added on December 27, 2012, 9:19 amcurious, what do u all make use for the GPIO pin? connect to arduino? connect to various sensor?

This post has been edited by aba9785: Dec 27 2012, 09:19 AM
aba9785
post Dec 27 2012, 01:12 PM

el aba9785
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743 posts

Joined: Jun 2005
From: Penang


QUOTE(C-Fu @ Dec 27 2012, 12:17 PM)
wow.. thanks for sharing...

i m thinking of modifying it to become a simple RC car.
not sure how hard is it...

where u all usually get ur shield?
cytron? myduino? or other place?
aba9785
post Jan 4 2013, 08:52 AM

el aba9785
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Senior Member
743 posts

Joined: Jun 2005
From: Penang


QUOTE(satz @ Jan 3 2013, 03:36 PM)
Sensor model : Photoelectric sensor 10-30V NPN

The code in C++ must have multiple threads so that it could detect simultaneously for high speed movements.

Yeah, totally wireless, But do note that wireless adapter could disconnect every now and then, for a total headless operation,

Create a script to detect whether wireless is connected and run that script in a screen multiplexing software like, "GNU Screen" or use crontab, scheduling software.

Yup, port forwarding will allow external access.
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regarding the wireless adapter would disconnect once a while.... do u manage to root cause the issue?
is it hardware? (wifi adapter/ wifi router), power surge? (i think u r using a battery pack?), software? (RPI is not that powerful, just adequate. or is ur code?), or location? (where u place the router/rpi box)?


QUOTE(intothefantasy @ Jan 3 2013, 07:09 PM)
hmm question..tried this raspberry and seems awesome but it could not detect my 2.5 WD pasport hdd...is it because of not enough power? it is 500gb size....
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how do u connect the RPI? direct into RPI usb slot?
if u direct into RPI slot, u might wanna try to power ur rpi using a 2A USB port (eg: ipad/tab charger)
aba9785
post Jan 4 2013, 03:45 PM

el aba9785
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Senior Member
743 posts

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From: Penang


QUOTE(intothefantasy @ Jan 4 2013, 03:40 PM)
hmm u means the ipad charger is the plug head right? that will allow usb to connect to it? if yes i will try it later since i have that
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yup. the plug head thing.
let me find the photo
» Click to show Spoiler - click again to hide... «

aba9785
post Jan 5 2013, 09:05 PM

el aba9785
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From: Penang


QUOTE(satz @ Jan 5 2013, 12:19 PM)
For the wireless adapter part, m not that sure on whats the issue, but i guess my issue was the distance
or the adapter power down when no activity. Because when the browser access the web server,
the wireless adapter tend to work non stop.. But when no devices access the internal webserver,
the wireless adapter tend to disconnect from the router. So i had to restart the whole pi.
The distance between the router and rpi box is approximately 6 meters.

So create a script which will check the wireless connection every 1 or 5 minutes and
script run ifconfig wlan0 down and ifconfig wlan0 up if in case connection breaks.
As the whole operation is headless, GNU screen is very useful. The program/script will
still run eventhough our terminal session ends.
Level shifter with circuit diagram planning - 3 days
C/C++ program - 7 days
PHP web output - 4 days

Took me approximately 2 weeks.
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my friend last time try to check for wifi data collision thing using an app on his android phone
he use this method to find/locate best location/placing for his config/setup.
let me ask him what is the name of the app.

not sure if anyone else know of the app name/other method to check for wifi data collision thing
aba9785
post Jan 5 2013, 09:19 PM

el aba9785
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From: Penang


QUOTE(satz @ Jan 5 2013, 09:09 PM)
u mean due to the wifi channels ?
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i'm not really a RF engineer/background, but this is what i roughly know.

A Wi-Fi station will transmit only if it thinks the channel is clear. All transmissions are acknowledged, so if a station does not receive an acknowledgement, it assumes a collision occurred and retries after a random waiting interval.

you can read more here.
http://revolutionwifi.blogspot.com/2011/03...rier-sense.html

or google 'wifi collision detection' (while i try to ask my friend more, should be tmr or monday cos i cant find him now)
aba9785
post Jan 5 2013, 09:27 PM

el aba9785
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From: Penang


QUOTE(satz @ Jan 5 2013, 09:23 PM)
if i am not mistaken usually due to channel overlapping,

channel 1,6,11 are the best as most router comes with either channel 6 or auto channel. But the weird part is my router is the only one in the office.

Or could it be the adapter self sleep when there is no activity ?
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hmm... u seems to know more than me blush.gif

r u doing it as final year project?
not sure if ur lecturer will allow u to put that problem (wifi issue) as future enhancement or not.
or just pretend everything is ok for the first 30 mins laugh.gif
aba9785
post Jan 6 2013, 03:41 PM

el aba9785
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743 posts

Joined: Jun 2005
From: Penang


QUOTE(satz @ Jan 5 2013, 11:58 PM)
No la, i just came across the channel overlapping part when we r trying to bond
& link aggregate multiple network interfaces in linux. When wireless networks
under same channel, link aggregation works but bandwidth doesn't multiply.

Then only i found out about it in wikipedia : (channel 1,6,11)
http://en.wikipedia.org/wiki/List_of_WLAN_channels

Not final year, its a small R&D for a factory (counting purpose), wireless & portable.

Wifi do disconnect, but there will be a script running every 1 minute, so
wifi will reconnect automatically. smile.gif

I cant submit this as my fyp either because m pursuing chemical engineering.  tongue.gif
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i see. so u r using a script to reconnect every minute, seems like a workaround but in case, i think should be ok
cos cheaper n less work thumbup.gif

QUOTE(I<3LYN @ Jan 6 2013, 12:31 AM)
I just made a laser-cut clear acrylic case for my pi  brows.gif

if anyone want a laser-cut acrylic case, please let me know  biggrin.gif
*
UGPM
aba9785
post Jan 7 2013, 09:07 AM

el aba9785
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743 posts

Joined: Jun 2005
From: Penang


QUOTE(C-Fu @ Jan 7 2013, 01:58 AM)
If you guys read this thread here
http://www.raspberrypi.org/phpBB3/viewtopi...=22158&start=75

you can see how people are dissapointed with RPi Foundation's stance on Android - which, to summarise... will not be officially supported anytime soon.

simply put, they don't care about android on RPi. and they certainly won't care if broadcomm - the makers of RPi's graphics chip - officially supports android development nor release the code for RPi.
while it is understandable that the Foundation's view of Raspberry Pi is for education, they just don't want to care if we use it for anything OTHER than for educational purpose, in the strictest sense of word.

aisehhhhh doh.gif
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not sure if it just me or what.
i can just get those cheap android TV (mk802) for around rm200, comes with a keyboard/mouse/controller

for RPI, i need to add extra keyboard, mouse, wifi adapter, powered usb hub, etc... it will cost me over rm200 (including rpi + sd card)

if i want a android UI/something that just work, for the cost vs benefit wise, i would just choose those cheap android tv (can get from garage sales, ebay, etc)

if i want NAS/BT server/media player/web server/cheap pc/lots of modding/diy/home automation (+arduino)/toy (big boys toy) = i would get RPI


btw, no offend to u...
hopefully i didnt annoy u
aba9785
post Jan 10 2013, 03:42 PM

el aba9785
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From: Penang


QUOTE(quikstep @ Jan 10 2013, 03:09 PM)
sort of right with the polyfuse but then again, maybe some usb hubs protect the current surge but this rm 15 hub i have does not. i first experienced it when plugging to the hub. i tot my hub faulty. then plug to usb port directly. same same.  doh.gif . decided to contact element14 for RMA. hopefully they comply.
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are there any confirmed working powered hub that is confirm working for rpi (prefer less fault, less reset)

even though i m using a powered hub, my house there sometime got minor power surge/spike, changes in power voltage.

so far i dont plan to get voltage regulator... not sure if anyone facing this issue?
aba9785
post Jan 10 2013, 04:41 PM

el aba9785
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From: Penang


QUOTE(satz @ Jan 10 2013, 03:43 PM)
i am not sure about the others, but vztech 7 port one worked just nice for me.
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i see. maybe i will try a different hub later this weekend

QUOTE(quikstep @ Jan 10 2013, 03:49 PM)
i have a ATEN 4 port hub that I can power using 5v 1A. that one is ok.

my other VZTECH 4 port hub that also can be powered is not ok.
*
interesting... maybe is luck?
same model but not same behavior hmm.gif
aba9785
post Jan 17 2013, 09:01 AM

el aba9785
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From: Penang


QUOTE(C-Fu @ Jan 16 2013, 10:42 PM)
power rating?
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curious... is power rating important when using wifi adapter/usb powered stuff on RPI?
i m seeing some issue on my dlink wifi adapter.... let me snap n post it tonight/tmr.

 

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