- Power supply may not deliver enough power ("5 Volts" might only deliver 4.6 Volts, and cause problems)
- Old computer monitor cannot simply use HDMI-to-VGA cable (needs powered 'converter')
- Keyboard and mouse may not be 'verified' (most work, but worth checking, and using a USB hub
- SD Memory card size/speed, corruption, and copying 'disk image' issues (see esp 4.3 below for extra 'mini-gotchas', e.g. special software needed to copy files from laptop
- Configuration settings are hard (cryptic, and unexpected format)
- Think clearly about the 'total cost of ownership'
- Know where to get help - especially the many user forums
"Wow, this is great for my child! I can just grab an old keyboard, mouse, monitor, memory card and mobile phone charger, and we're ready to go!"
Whoa: not so fast.
Yes, the Raspberry Pi is an absolutely brilliant concept and fully-working product, and it is re-injecting a lot of energy and creativity into all the communities mentioned above. And the creators have never claimed anything like 'ready to go'. But, people are treating it that way, and there are a number of hurdles that are not entirely obvious to the first-time buyer, i.e. so-called 'gotchas' (as in 'I've got you, I've gotcha'), so I thought it would be useful to enumerate them and provide a few pointers and links. Remember, I am not trying to scare you off, or pour cold water on your enthusiasm. I love this thing, but I hate to see people running around in circles when a bit of care at the beginning could pre-empt a lot of headache. These remarks are especially aimed at those seeking to reuse common components already lying around the house (a great idea, and one of the attractions of the low-cost Pi). This first version has a number of Windows-specific remarks, but the general comments about hardware are relevant to all users.
In my opinion, if you do not address the following 'Gotcha List' right at the beginning your Raspberry Pi experience, you can spend a lot of time chasing false leads to fix problems that actually have a simpler root cause!
Gotcha ('got-you') List:
1. Power supply may not deliver enough power
[Technical followup] [User forums]
2. Computer monitor cannot just use 'adapter' cable
[User forum discussion on 'HDMI to VGA converter' issues]
3. Keyboard and mouse may not be 'verified'
4. Memory card challenges
4.2 Frequent on/off or sudden removal may corrupt the card
If your Pi stops working, or has intermittent problems such as those caused by underlying issues mentioned in sections 1, 2, or 3 above, you may suddenly remove the card, or indeed take out the power adapter or just turn it off and on again to restart the Pi. The problem is that the Pi may be in an 'in-between' state where it is in the middle of storing or updating information on the memory card, and you may end up with the card in a corrupted state which makes the Pi operate very erratically the next time, or not at all. You therefore need to be careful, and in particular try to halt the Pi properly with the command
before unplugging it or turning off the power. Note that 'sudo' is shorthand for 'Super User Do the following command', and temporarily grants you the permission to execute that command; not all commands or users are eligible for this, but this command should work when you are logged in as the user called 'pi' as explained in the Raspberry Pi Quick Start guide. You'll have to read more about Linux commands to understand more: a good place to start is to search the web for linux e-books or dummies' guides, and also look at the Raspberry Pi forums about this topic.
4.3 Creating/restoring fresh memory card contents is harder than it looks
(Gotcha 4.3c: if you go to the recommended site to obtain Win32DiskImager, you see the message 'No download files exist for this project')
5. Configuration settings are hard
5.1 Proceed slowly and make small changes
Too many changes make it hard to do incremental 'controlled experiments' to figure out what has gone wrong.
5.2 If possible, make the changes directly on the SD card
In other words, make these changes while working on the Raspberry Pi, using the simple supplied editor called nano. To edit the file config.txt for example, you need to know that from the Linux point of view it sites in a directory (i.e. folder) called 'boot', and the command to start the editing is as follows:
sudo nano -B /boot/config.txt
- 'sudo' is 'Super User Do' as explained above.
- 'nano' is the command to invoke the nano editor
- -B is a special flag to ensure a backup is created, in the case called /boot/config.txt~
- /boot/config.txt is the actual file you will be editing
5.3 If editing via Windows, use a true plain text editor like 'Notepad++'
Powerful text processors such as Word, and even ordinary 'Notepad', may display and/or save files in the wrong format (e.g. the conventions for end of line are different in Windows and Linux), so it is often preferable to use a 3rd-party tool such as 'Notepad++' which does the right thing.
5.4 Try to understand what the settings actually do
- About config.txt and how to edit it on different operating systems
- A detailed description of what most of the settings do.
- A help forum posting about video/monitor settings.
6. Think clearly about the 'total cost of ownership'
7. Know where to get help - especially the many user forums
- RaspberryPi.org Forum, including great links to Community, Education, Projects, and more
- Elinux.org Raspberry Pi Wiki/Hub (wonderful and thorough collection of resources and ideas: look especially at Getting Started, Resources, and Community)
- Stackexchange Rapberry Pi discussions (great technical/troubleshooting resource: click on 'tags' or 'questions' or just enter a search phrase)
That's it, folks! Now go and explore, and enjoy!
Please feel free to re-use any/all of the above comments, but attribution by linking to
would be appreciated. Comments and corrections are also appreciated.
-Marc E, 16th April 2013