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and USB 2.0 is limited to half-duplex rates. Because USB 3.0 is backward-compatible
to USB 2.0, this is not a problem, but you won't get USB 3.0 speeds out of the drive.
Whether you buy a premade external drive or use a separate chassis, you want to
make sure it draws its power from the USB port, not from an external adapter. If it did
that, you'd have something else you needed to plug into the inverter, and that really
isn't necessary.
You should also remember that you cannot boot your Raspberry Pi from this SSD.
You'll just be mounting it as a storage partition where you will put your movies.
Touchscreen
You could use a TV or a monitor that connects to the Pi's video outputs (either HDMI
or composite), but then you'd have to interface with the Raspberry Pi through a key-
board or a mouse, and that's not ideal in a moving car (definitely not if you want your
kids to use this setup from the backseat).
Instead, this hack uses a touchscreen. If you've been looking through this topic, you
may have noticed we have a separate hack ( Hack #50 ) that covers how to add a
touchscreen to a Raspberry Pi, but that particular type of touchscreen is not a good
choice here. It is a DisplayLink device, which means it doesn't use the HDMI or com-
posite outputs on the Raspberry Pi. Since the Raspberry Pi can decode hardware
video using only those output devices, you'll need a touchscreen that is connected to
them (instead of just over USB).
The part we found for this came from a company called Chinavasion, with the highly
descriptive name of 7 Inch HD Touchscreen Car Monitor . This nifty little unit supports
HDMI input at 1720x1440 (not quite 1080p, but still, not shabby), but it also has an
integrated touchscreen with Linux support. It is not super cheap (about $150 at the
time of this writing), but it is designed for use in a car, so it comes with a native 12 V
power cable.
Powered USB Hub
You'll need a powered USB hub. Hypothetically, you could try to get away with just
plugging your touchscreen and SSD into the Raspberry Pi directly, but practically,
we're telling you not to try that. Your Pi is far more likely to simply turn off when you
try that, and you won't be able to attach any other components, like a keyboard or
mouse (for debugging the setup) or a wireless network controller (for downloading
files or connecting to the Internet from a coffee shop on the road).
The brand or model doesn't matter so much here. The most important detail is this:
it needs to be externally powered. You need to be able to plug it into the wall, or in this
case, into the inverter plugged into the 12 V receptacle. Many inexpensive USB hubs
 
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