Sunday, August 10, 2014

Building a RaspberryPi Time Capsule: The cheap, fast and simple guide

I am a longtime fan of Apples "Timemachine" data backup software. Having used multiple flavours of backup software on Linux and Windows, Timemachine has been by far the simplest and easiest one to use. In its simplest form, you only need to plug in a bog-standard hard drive into your Macbook to save your backups. But what if you couldn't even be bothered plugging in a USB drive? Is there a way to do it wirelessly? Good news! Apple sell a wireless backup solution, the "Time Capsule". The bad news? Its $350. There is, however, a cheaper solution.

Since the Raspberry Pi hobbyist development board came out, there have been many guides written on how to convert it into an Apple Timemachine compatible device. Although they work, I have found them to be overly complicated for what has to be done. Also, they require that the Raspberry Pi has a static IP, something that is inconvenient if you want to set up your backup on a new network when you move house, for example. Thankfully, I found one guide that offered a simpler solution. This guide removed much of the un-needed steps from the previous guides. This guide does require that you do the first preliminary backup over the network. For me, with over 300Gb of data to backup, this would have taken over 24 hours to transfer. It is much faster to do the preliminary backup over USB. As such, I have merged the two guides above into one, cheap, fast and simple Raspberry Pi - Time Capsule guide. 

Parts list


  1. SD card
  2. Raspberry Pi
  3. 3.5mm Portable Harddrive 


  1. USB Wifi dongle 
  2. Philips screwdriver
  3. Sharp blade
  4. Mini USB cable 
  5. Soldering iron and solder

Setting up the Hard drive 

  1. Plug your USB into your Macbook. 
  2. Click on Applications - System Preferences - Time Machine. 
  3. Tell Time Machine which drive to use for backups by clicking the “Select Backup Disk…” button, selecting your newly plugged in drive, then clicking the “Use for Backup” button. 
  4. Time Machine will schedule your first backup to start in just two minutes. You will have to wait a while, as this can take a few hours. 
  5. Unplug the hard drive when done. 

Setting up and configuring the Raspberry Pi 

  1. Download the latest "Raspbian" OS image file for the Raspberry Pi. Dont download the "NOOB" version, as this will require that you use a TV to set it up. We will be using SSH in this guide. 
  2. Burn the OS image to the Raspberry Pi. If you are using OSX, use "RPi Easy SD card setup" app. This will take about 20min. Dont worry if you get an error saying "Could not eject card" at the end. It should have completed successfully. 
  3. Put the SD card in the Raspberry Pi. Connect an ethernet cable from the Raspberry Pi to your router. Power up the Raspberry Pi. 
  4. Log into your router on your internet browser and get the IP address of the Raspberry Pi. You can also get this using a TV connected to the Raspberry Pi. 
  5. Open a terminal in OSX, and ssh into the raspberry Pi. The password is "raspberry"
    $ssh pi@THEIPADDRESS 
  6. Update software on the device
    $sudo apt-get update 
    $sudo apt-get upgrade 
  7. Install the software that we will need. Netatalk is used for creating NFS shares, the others are used for reading the HFS formatted USB drive
    $sudo apt-get install netatalk 
    $sudo apt-get install hfsplus hfsutils hfsprogs 
  8. Edit the fstab file to automatically mount the usb drive on boot up
    $sudo nano /etc/fstab 
  9. Add the following lines, then ctrl + c to save and exit. Note: "sda2" was the partition on my USB drive that needed to be mounted. Yours may be sda1. Run "dmesg" to see which one you will have to mount. 
    /dev/sda2 /mnt/TimeMachine hfsplus rw,force,exec,auto,users 0 3
  10. Open up the permissions of the mount directory
    $sudo chmod 777 /mnt/TimeMachine
  11. Attempt to mount the usb drive:
    $sudo mount /dev/sda1 
    If it mounted successfully, try and write to the USB drive using "mkdir /mnt/Timemachine/testDir". Note: if you reboot the Raspberry Pi and the line in the fstab is not correct, the raspberry Pi will not boot up properly again. The easiest way to recover will be to write a new raspbian image to it. Also use the mount command to check that /dev/sda2 is mapped to /mnt/TimeMachine. Make sure that the letters rw are in the same result. This ensures that we have read/write access to the partition.
  12. Add the directory to the "Pi" user (the user that you will be logging in from your macbook with)
    $sudo chown -R pi /mnt/TimeMachine 
  13. Edit the Netatalk config file to share the Timemachine directory
    $sudo nano /etc/netatalk/AppleVolumes.default 
    Add the following line to the end, save and exit.
    /mnt/TimeMachine "Time Machine" options:tm 
  14. Restart netatalk
    $sudo service netatalk restart 
  15. Back on your macbook, a share called "raspberrypi" should appear on the left side of your finder window. If not, in finder, click on Go - Connect to server and type "afp://raspberrypi" or "afp://IPADDRESSOFRASPBERRYPI" into the address window. After you press enter, the shared directory should appear.
  16. Go into Timemachine again. Remove the previous backup disk. Click on "select disk" and select the raspberry Pi. It will prompt your for a username and password. Use "pi" for the username and "raspberry" for the password.
  17. Thats it! The macbook should recognise the previous backup and continue from there. After the previous backup over USB, the second backup over wireless should be alot faster.

Enabling wireless on the RaspberryPi Time Capsule (optional)

You can remove the requirement of having an ethernet cable between the router and the Raspberry Pi by plugging in a small usb wifi dongle into the Raspberry Pi and configuring the wireless. I used a Ralink RT5370 from ebay for this. To connect your Raspberry Pi to the wireless network, here are the steps.

  1. SSH into the Raspberry Pi over ethernet (see above). 
  2. Install the WPA wireless tools
    sudo apt-get install wpasupplicant wireless-tools 
  3. Edit the networking file to use the wpa-supplicant file for wireless configuration
    sudo nano /etc/network/interfaces
    Ensure the wlan0 section uses the following lines:
    allow-hotplug wlan0
    iface wlan0 inet manual
    wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
    iface default inet dhcp
  4. Edit the wpa-supplicant file
    sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
    Ensure that it has the following lines
    ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
  5. Save the file, disconnect the ethernet cable, and reboot the Raspberry Pi. It should now connect to the wireless network.

Powering the Raspberry Pi off the hard drive (optional)

I did not want to have to have a separate power supply for the hard drive and the Raspberry Pi as both would be kept together at all times. As such, I looked into powering the Raspberry Pi off the supply of the hard drive. 
  1. Using a sharp knife, cut the male, full size usb connector off your mini usb cable, exposing the four wires. 
  2. Tape up the two data lines, we wont need them and we dont want them touching anything. They are normally the green and white wires. 
  3. Expose around 2mm of the conductor from the 5v (red) and ground (black) wires. Tin them with solder and the soldering iron. 
  4. Dismantle your portable hard drive. Each one will be different. For mine, I had to remove 4 screws from the underside, and slide out the harddrive and controller from one end.  
  5. Look for the four wires going from the controller to the hard drive. There should be two black, one yellow and one red. We are looking for the 5v wire (red) and either of the ground wires (black). Solder the red and black wires from the USB cable to the points on the controller board that the corresponding hard drive wires are soldered to. 
  6. Find a way to route the cable out of the portable hard drive caddy. I drilled a small hole with the screwdriver and pulled the usb cable through it. I also tied a knot in the cable on the end inside the caddy so that it would not get pulled out through the hole if it was tugged on. 
  7. Put everything back together, power up the portable hard drive, and plug in the Raspberry Pi. The raspberry Pi should power up successfully. 

Tuesday, April 29, 2014

Coding Python (Pydev) on Ubuntu 12.04 with Eclipse Juno

A short blog post. After having installed the latest pydev on the newest eclipse juno, I found that python would not work. All the relevant buttons for python development did not appear, even though the software manager reported that pydev was installed. As such, to get both working correctly I had to do the following:

  1. Following this guide, as far as installing pydev. However, do not go any further as installing pydev 3.0 didnt seem to work. Niether did it work on Eclipse kepler 4.0.3. A similiar issue was reported here:
  2. As such, when eclipse is installed, go to help-> install new software. For the source, type: “”. 
  3. Uncheck “show only the latest versions of available software”. 
  4. Select Pydev for Eclipse version 2.8.2.
  5. Works!

Monday, April 28, 2014

Correcting incorrect time-offset on an Ubuntu server

Here is a quick post on a solution to an issue that affected my Ubuntu server. I noticed that me cron jobs were getting executed about a hour or two later than they were set to run at. Logging into the server and running the command "date" confirmed what I easily suspected: that the clock was off by 1h 45min.

Running the command:
$sudo ntpdate
to update the clock returned the error
ntpdate - no servers can be used, exiting.
So then I ran the command
$sudo ntpdate"
which returned the following:
28 Apr 14:28:40 ntpdate[23357]: step time server offset 2311.837165 sec.
Great, I thought, problem solved. Unfortunately not. When I ran the command "date" again, the server was still off by an hour:
Mon Apr 28 14:33:45 UTC 2014.
It was actually 15.33. Suspecting an issue with Daylight Savings Time (DST) was the issue, or to be more specific, that the server wasnt using it, I looked to enable it. A quick Google informed me that an Ubuntu installation gets its DST settings from knowledge of its physical location, and the time server that it is conencted to. I had already configured it to use a suitable time server with the command "$ sudo ntpdate", so I had to reconfigure its location from the terminal. To do this, run the following command:
$sudo dpkg-reconfigure tzdata
You will be presented with a terminal GUI. Select your locality. Then when completed, you will be greeted by the updated time: 
Current default time zone: 'Europe/Dublin'
Local time is now:      Mon Apr 28 15:33:45 IST 2014. Universal Time is now:  Mon Apr 28 14:33:45 UTC 2014.
Running "date" now confirms the corrected time:
Mon Apr 28 15:33:56 IST 2014

Problem solved! 

Tuesday, January 7, 2014

Repairing intermittent wifi/wireless on a 15" Macbook Pro 2011

From reading a couple of articles on this site, you may have noticed that although I may be critical of some Apple goods, in general, I am a fan. However, there are some times that I am extremely fustrated when their hardware breaks, such as when my MacBook Pro 15" wifi decided to start acting abnormally. For reference, it have a Macbook Pro 15" Unibody Early 2011 (Released February 2011 2.2 GHz Quad-core Intel Core i7 Processor, thunderbolt, Broadcom BCM94331PCIEBT4AX wifi/bluetooth card)

The issue
After a while of use, the wireless internet dies. The signal strength indicator fan in the top right corner still indicates five full bars. Right Clicking on the icon and clicking on "Turn wi-fi off" makes the fan icon go blank as it should, but the previously connected to network remains in the list check marked, which it shouldnt. All other wifi networks in the area disappear from the list. The status at the top of the drop down box says "Wi-Fi: looking for networks".
Right clicking on the icon and clicking on "Turn wifi-off" makes the icon go blank, as it should. Right-clicking on the icon and clicking on "Turn Wifi-On" does not enable the wifi. The fan icon stays blank, which it shouldn't. The previously "connected to" network remains check marked, but there is no connection to the internet.
Putting the laptop to sleep with the lid and waking it again results in five faded bars, but now no wifi networks can be found, and there is no connection to the internet. The issue occurred round once a day at the beginning. By saving my work and rebooting the laptop, the issue has been manageable. However, it became unmanageable when it occurred more and more often to the point where I had to save my work reboot my laptop every 1-2 hours of use.

What I tried to do to repair the issue

  1. Reboot the laptop. A temporary solution is to reboot the laptop, in which the wifi performs as it should until the issue occurs again.
  2. Use a USB dongle. A semi permanent solution was for me to buy a Ralink usb wifi adapter, that worked fine but was not ideal. It felt a bit ridiculous and cumbersome to have to use a $10 usb adapter to repair a Macbook Pro that cost $2000.
  3. Connect to a different wifi network. This did not work. The issue occurs when connected to other wifi networks, such as my parents one at home. This hinted that it was not a wireless router issue.
  4. Reset PRAM, NRAM, etc. This was only a temporary solution, as was just simply rebooting the laptop.
  5. Deleting my Airport settings files. Again, this was only a temporary solution, bus so was simply rebooting.
  6. Wiped the harddrive and installed Mountain Lion. The issue remained, even with a clean installation with no restoration of my old settings from TimeMachine. The issue was the same when I installed Lion, and Mavericks. I even noticed the same issue once with the wifi when I booted off just the OSX installation disk. As such, I believed that the the issue is hardware related.
  7. Visual inspection of the hardware. I took off the bottom cover of the laptop to see if there are any visually obvious loose connections, but there are none.
  8. Took the laptop to an authorised Apple Repair Center. They did nothing. As it was an intermittent issue, they said that the wifi was working fine when they ran their DVD of hardware tests. As far as I know, they don't do any long-term tests, even though I had requested them to do so. They blamed the wireless router (which I knew was not an issue, see above) and mu wifi settings (which I also knew was not an issue, see above).
  9. Replaced the wifi card. This did not work. I bought a new Broadcom BCM94331PCIEBT4AX for around $35 off eBay. Following a guide on ifixit, ooth+Cable+Replacement/5887 I replaced the card easily enough. It was just around 10 screws in total, easily manageable in an hour if you take your time. Unfortunately, the issue returned again after a few hours of use. 
  10. Replaced the motherboard, and the screen. I assume means that the wifi antennas got replaced. This did not work. On an unrelated issue with the graphics card, Apple agreed to replace the motherboard, LVDS, and LCD screen out of warranty (really good of them). Unfortunately, their authorised repair center took nearly 6 months to do the repair (again, they were a bad representation of Apple). Unfortunately, the wifi issue returned once again after a few hours of work.

What repaired it in the end
Finally, in a last ditch attempt, and as it seemed to be the only part in the laptop not replaced (including software), I bought a replacement wifi/bluetooth cable off ebay for around $30. This worked! It has been going strong now for nearly three weeks with no drop in wifi. It was pretty expensive for a simple black ribbon cable but I am glad that it worked. There was no visual damage to the old cable, but I suspect myself that the bottom cover may have pinched the cable against some edge near the motherboard, thus causing the intermittent drop-off in wifi.

Update 20/01/2013 : I have re-opened the laptop to inspect the location of the ribbon cable (Figure 1). In (Figure 2) you can see the point on the rear of bottom cover (2) that places pressure on the end of the ribbon cable. You can see that there is a visible imprint on the plastic foil covering the back of where they are in contact. Due to the level of imprint and its location, I suspect that this causes excess pressure on the cable connector when the laptop receives knocks from the underside.

Figure 1: The faulty macbook wifi cable is shown in (1). The point on the back cover that I suspect may have been putting too much pressure on the ribbon cable is located at (2)

Figure 2: The point on the rear of bottom cover (2) that places pressure on the end of the ribbon cable. You can see that there is a visible imprint on the plastic foil covering the back of where they are in contact. Due to the level of imprint and its location, I suspect that this causes excess pressure on the cable connector when the laptop receives knocks from the underside.