Recovery Pi

17 07 2012

My previous single Raspberry Pi posts have been steps towards my “Recovery Pi”

a small self sufficient system that can be shipped to
a remote site to facilitate serial (console) & network
(mgmt lan) connectivity to the remote devices

• Raspberry Pi ($45)
http://www.raspberrypi.org/faqs

• USB->Serial Convertor ($30)
http://www.jaycar.com.au/productView.asp?ID=XC4834

• Cisco Console Cable

• Telstra 3G “Elite” USB Modem ($29)
http://www.telstra.com.au/internet/mobile-broadband-prepaid/get-started/#tab-elite-usb
– Telstra AUS Mobile Internet $180/year (365 day access | 1.46c per MB in AUS | $15.36 per MB Intl Roaming)

• 8GB SDHC Mem Card ($10)

• USB Power Brick (~10hrs run) ($20)
http://www.tevion-cameras.com/popups/MPP_7400_au_popup_02/

• USB Powered Hub ($18)
http://hakshop.myshopify.com/products/usb-powered-hub

• Total Retail Startup Cost: $152 AUD


===Built on the existing Debian Squeeze image===

http://downloads.raspberrypi.org/images/debian/6/debian6-19-04-2012/debian6-19-04-2012.zip

===Telstra 3G USB Modem===

root@raspberrypi:~# apt-get install usb-modeswitch pppd

root@raspberrypi:~# dmesg | grep ttyUSB
usb 1-1.2.4: GSM modem (1-port) converter now attached to ttyUSB0
usb 1-1.2.4: GSM modem (1-port) converter now attached to ttyUSB1
usb 1-1.2.4: GSM modem (1-port) converter now attached to ttyUSB2
usb 1-1.2.3: pl2303 converter now attached to ttyUSB3

root@raspberrypi:~# cat /etc/chatscripts/telstra
ABORT ‘NO CARRIER’
ABORT ‘NO DIALTONE’
ABORT ‘BUSY’
ABORT ‘ERROR’
ABORT ‘NO ANSWER’
” ‘ATZ’
OK ‘AT&F’
OK ‘ATQ0 V1 E1′
OK ‘AT&D2 &C1′
OK ‘AT+FCLASS=0′
OK ‘ATS0=0′
OK ‘AT+CGDCONT=1,”IP”,”telstra.internet”‘
OK ‘ATDT*99#’
CONNECT ”

root@raspberrypi:~# cat /etc/ppp/peers/telstra
/dev/ttyUSB2
460800
modem
crtscts
defaultroute
noipdefault
usepeerdns
ktune
noauth
lock
nobsdcomp
novj
connect “/usr/sbin/chat -v -f /chatscripts/telstra”

root@raspberrypi:~# pon

root@raspberrypi:~# ifconfig ppp0
ppp0      Link encap:Point-to-Point Protocol
inet addr:10.138.162.113  P-t-P:10.64.64.64  Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP PROMISC MULTICAST  MTU:1500  Metric:1
RX packets:705 errors:0 dropped:0 overruns:0 frame:0
TX packets:624 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:621353 (606.7 KiB)  TX bytes:40301 (39.3 KiB)

root@raspberrypi:~# poff

===3G Connection On Boot===

root@raspberrypi:~# cat /etc/network/interfaces
# Used by ifup(8) and ifdown(8). See the interfaces(5) manpage or
# /usr/share/doc/ifupdown/examples for more information.

auto lo
iface lo inet loopback

auto ppp0
iface ppp0 inet ppp
provider telstra

===Reverse SSH Connection & AutoSSH===

root@raspberrypi:~# ssh-keygen

root@raspberrypi:~# ssh-copy-id recoverypi@jumphost

-Manual-
root@raspberrypi:~# ssh -R 2222:localhost:22 recoverypi@jumphost

-Auto-
root@raspberrypi:~# apt-get install autossh

root@raspberrypi:~# autossh -M 20000 -f -N -R 2222:localhost:22 recoverypi@jumphost  -i /root/.ssh/id_rsa

Add the command into /etc/rc.local before the “exit 0” line & you are good to go on every reboot.

autossh -M 20000 -f -N -R 2222:localhost:22 recoverypi@jumphost  -i /root/.ssh/id_rsa

– Connect to your JumpBox & verify the Pi has “phoned home”

recoverypi@jumpbox:~$ netstat -ant | grep 2222
tcp 0 0 127.0.0.1:2222 0.0.0.0:* LISTEN
tcp6 0 0 ::1:2222 :::* LISTEN

– Connect across the reverse SSH tunnel to the Pi

recoverypi@jumpbox:~$ ssh root@127.0.0.1 -p 2222
root@127.0.0.1’s password:
Linux raspberrypi 3.1.9+ #84 Fri Apr 13 12:27:52 BST 2012 armv6l

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Tue Jul 17 22:27:42 2012 from raspberrypi
root@raspberrypi:~#

===MINICOM===

root@raspberrypi:~# apt-get install minicom

root@raspberrypi:~# minicom -D /dev/ttyUSB3 -b 9600 -o

Welcome to minicom 2.4

OPTIONS: I18n
Compiled on Sep  7 2010, 01:26:06.
Port /dev/ttyUSB3

Press CTRL-A Z for help on special keys

border-rtr>
border-rtr>en
Password:
border-rtr#sh ver
Cisco Internetwork Operating System Software
IOS ™ C2600 Software (C2600-IO3-M), Version 12.2(46a), RELEASE SOFTWARE (fc1)

===TFTP===

root@raspberrypi:~# apt-get install xinetd tftpd tftp

root@raspberrypi:~# vi /etc/xinetd.d/tftp

————————————-
service tftp
{
protocol        = udp
port            = 69
socket_type     = dgram
wait            = yes
user            = nobody
server          = /usr/sbin/in.tftpd
server_args     = /tftpboot
disable         = no
}
————————————-

root@raspberrypi:~# mkdir /tftpboot
root@raspberrypi:~# chmod -R 777 /tftpboot
root@raspberrypi:~# chown -R nobody /tftpboot

root@raspberrypi:~# /etc/init.d/xinetd stop
Stopping internet superserver: xinetd.
root@raspberrypi:~# /etc/init.d/xinetd start
Starting internet superserver: xinetd.
root@raspberrypi:~#






Raspberry Pi Runtime on Battery

4 07 2012

In a previous post, I mentioned the battery pack I bought from our local Aldi store “Tevion MPP 7400” – portable 7400mAh Li-Po Battery Pack. After many questions of “how long will it run” – I decided to find out.

I ran the Pi on this with the USB Wireless NIC & USB->Serial Console cable until it ran no more – and to my surprise, this nearly ran for 11 hours straight.

10hrs 55minutes to be exact

 22:17:01 up 10:55,  1 user,  load average: 0.00, 0.01, 0.05

Sooooo – with that runtime – it should give plenty of portable time on target between charges.





Telstra 3G Raspberry Pi

3 07 2012

Bringing a couple of my previous posts together, I finally got my Telstra 3G dongle to work on the Raspberry Pi.

First challenge was the device detecting as a CD-Rom (to make it easier for Windoze users). This is quickly solved by installing usb_modeswitch (notice the change from device 19d2:2000 (presented as CD-Rom) to 19d2:0031 (The USB modem mode)

root@raspberrypi:~# lsusb | grep ZTE
Bus 001 Device 004: ID 19d2:2000 ONDA Communication S.p.A. ZTE MF627/MF628/MF628+/MF636+ HSDPA/HSUPA

root@raspberrypi:~# apt-get install usb-modeswitch

root@raspberrypi:~# lsusb | grep ZTE
Bus 001 Device 005: ID 19d2:0031 ONDA Communication S.p.A. ZTE MF110/MF636

Unplugging plugging the dongle back in now gives you the ttyUSB devices you need.

root@raspberrypi:~# dmesg | grep ttyUSB
usb 1-1.2.3: GSM modem (1-port) converter now attached to ttyUSB0
usb 1-1.2.3: GSM modem (1-port) converter now attached to ttyUSB1
usb 1-1.2.3: GSM modem (1-port) converter now attached to ttyUSB2
usb 1-1.2.3: GSM modem (1-port) converter now attached to ttyUSB3

The easy thing to do would to to use the sakis3g script – its compiled for arm ….. but I couldnt get it to work, it would just fail to connect.

Next easiest thing would be to use wvdial …. however this isnt ported to arm …. dammit

So, its back to pppd & chat scripts.

root@raspberrypi:~# cat telstra.chat
ABORT ‘NO CARRIER’
ABORT ‘NO DIALTONE’
ABORT ‘BUSY’
ABORT ‘ERROR’
ABORT ‘NO ANSWER’
” ‘ATZ’
OK ‘AT&F’
OK ‘ATQ0 V1 E1’
OK ‘AT&D2 &C1’
OK ‘AT+FCLASS=0’
OK ‘ATS0=0’
OK ‘AT+CGDCONT=1,”IP”,”telstra.internet”‘
OK ‘ATDT*99#’
CONNECT ”

root@raspberrypi:~# /usr/sbin/pppd /dev/ttyUSB2 460800 modem crtscts defaultroute noipdefault usepeerdns ktune noauth lock nobsdcomp novj connect “/usr/sbin/chat -v -f /root/telstra.chat”

At this point, the dongle light flashed, I did the victory dance & poured a drink – however it was short lived.

Looking at the logs in /var/log/messages – we see something wrong. ppp connects, but then the USB dongle disconnects (the bus resets) – bugger.

Jul  3 21:25:21 raspberrypi pppd[1619]: Serial connection established.
Jul  3 21:25:21 raspberrypi pppd[1619]: Using interface ppp0
Jul  3 21:25:21 raspberrypi pppd[1619]: Connect: ppp0 <–> /dev/ttyUSB2
Jul  3 21:25:22 raspberrypi pppd[1619]: PAP authentication succeeded
Jul  3 21:25:22 raspberrypi pppd[1619]: kernel does not support PPP filtering
Jul  3 21:25:26 raspberrypi kernel: DEBUG:handle_hc_chhltd_intr_dma:: XactErr without NYET/NAK/ACK
Jul  3 21:25:26 raspberrypi kernel:
Jul  3 21:25:26 raspberrypi kernel: DEBUG:handle_hc_chhltd_intr_dma:: XactErr without NYET/NAK/ACK
Jul  3 21:25:26 raspberrypi kernel:

<snip>

Jul  3 21:25:28 raspberrypi kernel:
Jul  3 21:25:28 raspberrypi kernel: DEBUG:handle_hc_chhltd_intr_dma:: XactErr without NYET/NAK/ACK
Jul  3 21:25:28 raspberrypi kernel:
Jul  3 21:25:28 raspberrypi kernel: DEBUG:handle_hc_chhltd_intr_dma:: XactErr without NYET/NAK/ACK
Jul  3 21:25:28 raspberrypi kernel:
Jul  3 21:25:29 raspberrypi kernel: usb 1-1.2: USB disconnect, device number 8
Jul  3 21:25:29 raspberrypi kernel: option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
Jul  3 21:25:29 raspberrypi kernel: option 1-1.2:1.0: device disconnected
Jul  3 21:25:29 raspberrypi kernel: option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
Jul  3 21:25:29 raspberrypi kernel: option 1-1.2:1.1: device disconnected
Jul  3 21:25:29 raspberrypi pppd[1619]: Modem hangup
Jul  3 21:25:29 raspberrypi pppd[1619]: Connection terminated.
Jul  3 21:25:29 raspberrypi kernel: option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
Jul  3 21:25:29 raspberrypi kernel: option 1-1.2:1.3: device disconnected
Jul  3 21:25:29 raspberrypi kernel: option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
Jul  3 21:25:29 raspberrypi kernel: option 1-1.2:1.4: device disconnected

I had read about power causing issues on the USB devices, sometimes displaying these debug messages, so i tried using the 2A supply, but got the same result. I then tried out my funky new powered usb hub, courtesy of the crew @ Hak5.

Having the USB Data & USB Power plugs both in the Pi – it now works like a charm, the kernel debug messages are a thing of the past.

Jul  3 21:37:55 raspberrypi chat[1307]: CONNECT
Jul  3 21:37:55 raspberrypi chat[1307]:  — got it
Jul  3 21:37:55 raspberrypi chat[1307]: send (^M)
Jul  3 21:37:55 raspberrypi pppd[1305]: Serial connection established.
Jul  3 21:37:55 raspberrypi pppd[1305]: Using interface ppp0
Jul  3 21:37:55 raspberrypi pppd[1305]: Connect: ppp0 <–> /dev/ttyUSB2
Jul  3 21:37:56 raspberrypi pppd[1305]: PAP authentication succeeded
Jul  3 21:37:56 raspberrypi pppd[1305]: kernel does not support PPP filtering
Jul  3 21:37:58 raspberrypi pppd[1305]: Could not determine remote IP address: defaulting to 10.64.64.64
Jul  3 21:37:58 raspberrypi pppd[1305]: local  IP address 10.138.162.113
Jul  3 21:37:58 raspberrypi pppd[1305]: remote IP address 10.64.64.64
Jul  3 21:37:58 raspberrypi pppd[1305]: primary   DNS address 10.4.182.20
Jul  3 21:37:58 raspberrypi pppd[1305]: secondary DNS address 10.4.81.103

root@raspberrypi:~# ifconfig ppp0
ppp0      Link encap:Point-to-Point Protocol  
          inet addr:10.138.162.113  P-t-P:10.64.64.64  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:705 errors:0 dropped:0 overruns:0 frame:0
          TX packets:624 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3 
          RX bytes:621353 (606.7 KiB)  TX bytes:40301 (39.3 KiB)
root@raspberrypi:~# traceroute www.google.com
traceroute to www.google.com (74.125.237.148), 30 hops max, 60 byte packets
1  10.5.194.242 (10.5.194.242)  635.526 ms  674.257 ms  683.415 ms
2  * * *
3  * * *
4  Bundle-Ether12.fli8.Adelaide.telstra.net (120.151.255.29)  780.113 ms  779.887 ms  779.557 ms
5  Bundle-Ether1.fli-core1.Adelaide.telstra.net (203.50.11.9)  779.381 ms  779.129 ms  787.440 ms
6  Bundle-Ether9.win-core1.Melbourne.telstra.net (203.50.11.91)  787.405 ms  110.280 ms  105.926 ms
7  Bundle-Pos3.ken-core4.Sydney.telstra.net (203.50.11.12)  122.242 ms  122.008 ms  121.642 ms
8  Bundle-Ether1.ken39.Sydney.telstra.net (203.50.6.146)  134.345 ms  134.449 ms  149.559 ms
9  72.14.198.54 (72.14.198.54)  179.171 ms  179.048 ms  156.730 ms
10  66.249.95.226 (66.249.95.226)  115.508 ms  108.826 ms  118.016 ms
11  72.14.237.137 (72.14.237.137)  137.651 ms  125.653 ms  124.900 ms
12  syd01s13-in-f20.1e100.net (74.125.237.148)  119.918 ms  119.181 ms  118.817 ms
root@raspberrypi:~#




WiFi Pi

29 06 2012

The next logical step was to remove the dependency on physical ethernet cabling to my Raspberry Pi.

I struggled with a couple of cards, but eventually got success with a tiny little NG54/N150 Wireless USB Micro Adapter – WNA1000M.

I cant claim the credit – it was a combination of the following sites that eventually got a result.

http://www.69b.org/prox-pi.php/rpo/phpBB3/viewtopic.php?f=66&t=6737&sid=6f0540c1c93a8bd41b309c6832b6058b
http://www.ctrl-alt-del.cc/2012/05/raspberry-pi-meets-edimax-ew-7811un-wireless-ada.html
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=28&t=5249

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=26&t=6256
http://dl.dropbox.com/u/80256631/install-rtl8188cus.txt
http://dl.dropbox.com/u/80256631/install-rtl8188cus.sh

root@raspberrypi:~# apt-get install wget unzip wireless-tools wpasupplicant
root@raspberrypi:~# wget http://www.electrictea.co.uk/rpi/8192cu.ko
root@raspberrypi:~# wget ftp://ftp.dlink.com/Wireless/dwa130_revC/Drivers/dwa130_revC_drivers_linux_006.zip
root@raspberrypi:~# unzip dwa130_revC_drivers_linux_006.zip

root@raspberrypi:~# install -m 644 ./8192cu.ko /lib/modules/3.1.9+/kernel/drivers/net/wireless/
root@raspberrypi:~# depmod -a

root@raspberrypi:~# mkdir -p /usr/local/lib/firmware/RTL8192U
root@raspberrypi:~# mv rtl8192u_linux_2.6.0006.1031.2008/firmware/RTL8192U/* /usr/local/lib/firmware/RTL8192U/
root@raspberrypi:~# vi /etc/wpa_supplicant/wpa_supplicant.conf

root@raspberrypi:~# cat /etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
ap_scan=2

network={
ssid="WiFiNetworkSSID"
key_mgmt=WPA-PSK
proto=WPA2
pairwise=CCMP
group=CCMP
psk="C0mpl3xS3cur3P$K"
}
root@raspberrypi:~#

touch /etc/modprobe.d/blacklist.conf
echo "blacklist rtl8192cu" >> /etc/modprobe.d/blacklist.conf
touch /etc/modules
echo "8192cu" >> /etc/modules

**If your wifi is wlan2 or wlan3 etc - you can rename by deleting the old nics from ....

root@raspberrypi:~# vi /etc/udev/rules.d/70-persistent-net.rules

root@raspberrypi:~# vi /etc/network/interfaces

auto wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

And for the results:

root@raspberrypi:~# lsusb
Bus 001 Device 004: ID 0846:9041 NetGear, Inc. WNA1000M 802.11bgn [Realtek RTL8188CUS]

root@raspberrypi:~# iwconfig wlan0
wlan0     IEEE 802.11bgn  ESSID:"WiFiNetworkSSID"  Nickname:"<WIFI@REALTEK>"
          Mode:Managed  Frequency:2.447 GHz  Access Point: 02:5E:52:7A:AF:12   
          Bit Rate:150 Mb/s   Sensitivity:0/0  
          Retry:off   RTS thr:off   Fragment thr:off
          Encryption key:****-****-****-****-****-****-****-****   Security mode:open
          Power Management:off
          Link Quality=88/100  Signal level=88/100  Noise level=0/100
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

root@raspberrypi:~# ifconfig wlan0
wlan0     Link encap:Ethernet  HWaddr c4:3d:c7:79:3a:04  
          inet addr:192.168.0.140  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:261 errors:0 dropped:0 overruns:0 frame:0
          TX packets:140 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:53777 (52.5 KiB)  TX bytes:33212 (32.4 KiB)




Raspberry Pi Console Server

16 06 2012

It occurred to me that the Raspberry Pi would make a great low cost, portable console server.

1. Plug in a USB -> Serial convertor & appropriate serial console cable to your device

http://www.jaycar.com.au/productView.asp?ID=XC4834

Check that it is detected

root@raspberrypi:~# dmesg

usb 1-1.2: new full speed USB device number 5 using dwc_otg
usb 1-1.2: New USB device found, idVendor=067b, idProduct=2303
usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-1.2: Product: USB-Serial Controller D
usb 1-1.2: Manufacturer: Prolific Technology Inc.
usbcore: registered new interface driver usbserial
USB Serial support registered for generic
usbcore: registered new interface driver usbserial_generic
usbserial: USB Serial Driver core
USB Serial support registered for pl2303
pl2303 1-1.2:1.0: pl2303 converter detected
usb 1-1.2: pl2303 converter now attached to ttyUSB0
usbcore: registered new interface driver pl2303
pl2303: Prolific PL2303 USB to serial adaptor driver

Install minicom to drive it

root@raspberrypi:~# apt-get install minicom

Hurrah – Portable console access 😀

root@raspberrypi:~# minicom -D /dev/ttyUSB0 -b 9600 -o
Welcome to minicom 2.4

OPTIONS: I18n
Compiled on Sep 7 2010, 01:26:06.
Port /dev/ttyUSB0

Press CTRL-A Z for help on special keys
FORTIBORDER login: admin
Password: ************
Welcome !

FORTIBORDER # get system status
Version: FortiWiFi-60CM v4.0,build0535,120511 (MR3 Patch 7)
Virus-DB: 15.00698(2012-06-15 03:29)
Extended DB: 14.00000(2011-08-24 17:09)
IPS-DB: 3.00201(2012-06-14 00:30)
FortiClient application signature package: 1.496(2012-06-08 08:51)
Serial-Number: FW60CM3GXXXXXXXX
BIOS version: 04000018
System Part-Number: P08962-03
Log hard disk: Available
Internal Switch mode: interface
Hostname: FORTIBORDER
Operation Mode: NAT
Current virtual domain: root
Max number of virtual domains: 10
Virtual domains status: 1 in NAT mode, 0 in TP mode
Virtual domain configuration: disable
FIPS-CC mode: disable
Current HA mode: standalone
Distribution: International
Branch point: 535
Release Version Information: MR3 Patch 7
System time: Sat Jun 16 20:50:32 2012





My Raspberry Pi comes to life

16 06 2012

Like most of the rest of the world’s IT population, I got excited about the Pi & ordered one.

It has arrived & I have had a little bit of time to play with it & I am pretty impressed.

BUILD A CASE

The first thing to do was a case, I didnt want to short it out on anything & it just felt too fragile & vulnerable naked

I printed this one (http://www.raspberrypi.org/phpBB3/viewtopic.php?f=40&t=6500) on some card (manila folder) & folded it up

 

A larger selection can be found here: http://elinux.org/RPi_Cases

PREPARE A DISTRO

Next we need a Distro:

http://elinux.org/RaspberryPiBoardDistributions

For each image, just use dd in Linux **Be Careful – make sure you have the right device to write the image to. This would be the SD card, not your hard drive !!

dd if=.img of=/dev/sdb

I have been primarily playing with the Debian Squeeze distro

http://downloads.raspberrypi.org/images/debian/6/debian6-19-04-2012/debian6-19-04-2012.zip
User: pi / raspberry

Raspbian is based on Debian Wheezy, which is newer than Squeeze

http://www.raspbian.org/
User: root / raspbian

The developing Raspbmc (XBMC) looks very promising – I have watched a couple of movies with it, with no performance issues

http://wiki.xbmc.org/index.php?title=Raspbmc

http://www.raspbmc.com/2012/05/raspbmc-is-now-in-beta/

http://download.raspbmc.com/downloads/bin/ramdistribution/installer-testing.img.gz

Note: you need at least a 2GB SD card. Raspbmc will use the full size of your card.

**First boot needs internet (ethernet cable/ dhcp) – the installer prepares the sdcard, then raspbmc is downloaded & setup at first boot.

TIME FOR POWER

The Pi runs on 5v, connected via Micro USB http://elinux.org/RPi_Hardware_Basic_Setup#Power_Supply – which can be supplied by pretty much any phone charger / USB port these days. The only recommendation provided by the vendor is choose a supply that will provide 5v and ~700mA. They will apparently run “stable” on any voltage between  4.75 and 5.25 volts.

Many people have been using the iPhone / iPad chargers without any issues (me included). But as an experiment, I decided to see what they were putting out. The Pi has two test ports TP1 & TP2 – these are to check the voltage being supplied to the board. There are mutterings about voltages under 5volt providing unexpected behavior on some boards.

I found that my white iPhone/iPod power supply (Rated @ 5V 1A dropped to about 4.8v when the Pi is running with HDMI, SD Card & USB WiFi Dongle.

Apple (A1205) Drops to about 4.8V under load

My HTC charger (Rated @ 5V 1A)performed about the same – around 4.8v under load

HTC (TC P300) Drops to around 4.8V under load

Another generic branded “Switching power supply” that was also rated @ 5V 1A showed the same voltage drop to around 4.8V under load.

Enter the Samsung Galaxy Tab 5V 2A charger, this bad boy kept me running at 5V under load.

Samsung (ETA-P10X) Keeps pushing 5V under load

The general consensus is that a 5V 1A phone charger should be fine, but if you are planning on plugging things into the USB port (WiFi / Storage etc) then you would be probably best off getting a higher rated PSU. I am going to check out Jaycar for a regulated 5V 2A supply next. Your results may vary, I didnt experience any strange issues or performance problems when running of any of the listed PSUs – but possibly got more interface drops on the USB WiFi adapter (thats a subject for another blog post).

On the subject of power – having such a tiny / portable device is much more useful when you can take it with you away from a power point. From our local Aldi store, I picked up a “Tevion MPP 7400” This is a portable 7400mAh Li-Po Battery Pack. This little guy has two USB ports on it & will apparently provide up to 2.1A on one, or 1A each with both in use. Its primarily aimed at charging a smartphone on the go, but it works beautifully as a portable power supply for the Pi. I have not tested how long it will keep the Pi running, but I was playing on it for several hours without the pack dropping an LED on the power meter.

Battery Pack – providing 4.78V under load – just within the allowable range – so far no problems, but we will see how it goes.

Well, that’s it for now, my Pi lives and breathes (as much as a piece of electronic equipment can) – time to try out some more distros & “projects” with it.