Using a Laptop or Tablet as a CarPC



A laptop or tablet can make a good CarPC. This is partially due to lower power consumption and lower heat generation which are desired qualities for a CarPC. Most laptops possess these qualities and are purpose built to be mobile and efficient. Some laptops are better suited for this use than others, although just about any laptop can be used. There are a few unique challenges to a laptop install that should be addressed before diving in too deep. A highly portable unit will generally be a better choice than a huge desktop replacement type laptop.



One trend that is sure to grow rapidly as performance rises and price drops is to use an ultra portable mini PC; just slip it in its dock and the dock is wired to the car while the screen is in the dash. A really down and dirty way is just to mount it in a way that you just view the ultra portable itself, once transflective screens become more commonplace in these units this will be a good option for some to achieve an install without altering the vehicle much at all.



Choosing a laptop:



Many laptop installs are done with a laptop that the user may already have. However, choosing the right laptop specifically for the install is sometimes an advantage. A Pentium III 1.2GHz will perform similar to a standard via board, it can get the job done if you like the minimalist approach & have a good handle on your running services and optimize your system for the performance you have. They are relatively efficient partially due to their speed step technology.



If you have a choice try to avoid Pentium 4 laptops; this goes for p4m’s as well, they are the least efficient and generate the highest heat levels, and consume large amounts of power, then they also suffer as being more susceptible to being damaged by the heat they do generate, they require high amounts of airflow and large power supplies.



A good high performance choice would be a Pentium M, which is part of the Intel Centrino designation. These processors are very efficient and have some of the highest allowable core temperatures of all processors. They deal with the harsh environment of a vehicle install very well and perform well under the most extreme conditions and are thermally protected. This, combined with speed step throttling and a very efficient design with low power draw makes them a great choice. There are 3 variations of the M chips:

  • Regular M’s

  • Low voltage (LV)

  • Ultra low voltage (ULV)


A 1.2GHz ultra low voltage may sound anemic, but with their 2MB L2 cache and fast front side bus, they are very capable performers, a 1.2GHz ULV will far outperform a common VIA board, it will even outperform a 1.8GHz Pentium 4 while using literally half the power, they generate so little heat that there are laptops that don’t even use a fan with this processor, you can install one of these almost anywhere without worrying about airflow or overheating. Also worth mentioning is the Athalon XP-M’s, another good choice as a mobile processor.



If your budget allows, you can opt to go Core 2 Duo, which is inarguably the best mobile chip available at this time. While this would be considered way overkill by some, the Core 2 Duo’s are efficient enough to actually be an excellent choice There is no processor family available right now that is as efficient. If your goal is to look towards the future and ensure more than enough performance no matter what you throw at it, a Core 2 Duo may be the way to go.



As a general rule, avoid Pentium 4’s , even the Pentium 4 Mobile’s are very inefficient. They use a lot of power and build up excessive heat, add to this the fact that they don’t deal well with the heat they do generate, makes them a poor choice.



Installing the laptop



For as many different laptops as there are out there, there are almost as many different ways to install them. This may be determined in part by your willingness to either partially or even completely take the laptop apart. The easiest way to install a laptop is probably by using a laptop with a docking station, a docking station can usually eliminate the need to disassemble the laptop at all, as the power switch is usually available and easier to access right on the dock itself. This can be an ideal setup if you have thoughts of using the laptop outside of the vehicle on a regular basis, the drawback to this approach is it adds the burden of always making sure you have the laptop or the inconvenience of living without it if you want to just take a quick run to the store or something, this can be less of a problem if you chose to retain a head unit.



The power switch



Short of using a dock, most laptops will require at least partial disassembly to access the power switch. This is necessary to be able to remotely turn the computer on and off. Having to actually go to the laptop and turn it on each time is not desirable or acceptable. This is usually the most intimidating part for most people who are not experienced with disassembling expensive and delicate electronics, but it’s really not that difficult at all on most laptops, this is another area that some laptops are better than others with.



Some laptops with the power button on the area right above the keyboard can be downright easy, this panel is usually easy to remove without getting too intrusive to the assembly of the laptop case. Most laptops that have their power switch on the side of the laptop will be just a bit more difficult, they will usually require separating the lower case completely. Another design that is commonly used is the power switch on the screen bezel, these will require disassembling the bezel of the laptop, which is generally easier than disassembling the lower half.



You will need to extend 2 wires outside of the laptop to be able to control startup and shutdown. Some have been creative in the way to achieve this. One very clean way is to just wire the power switch to the useless regular modem jack. You can then use a telephone wire plugged in to run a remote switch on the dash or just as a way to wire in a startup/shutdown controller. Worse case for the severely electronically challenged, drop it off at any local electronics repair center, you should be able to get a tech to wire the power switch to the modem jack for around $75 give or take.



One alternative to the power switch approach is a wake on ring or wake on lan type setup, but this only works on some boards and reliability can be a bit questionable. If you are dead set against opening the laptop this can be an area to explore for some users.



The lid switch



Another area of concern with a laptop install that will use a complete intact laptop is the LID SWITCH. This switch is what triggers the laptop to shut down, hibernate or stand by depending on the settings within the operating system. Many times it’s enough to just select the “DO NOTHING” option in Windows and sometimes even in the BIOS, but some laptops may still have issues starting up reliably with the lid closed. This lid switch can be disabled if necessary, some may use a tiny pin switch at the joint of the screen hinge, some use magnet switches and some tablets have switches built into the hinge itself for auto rotation.



Custom case mods



If you’re willing to use the laptop as a dedicated CarPC you can choose to disassemble the laptop and remove the screen. You could then remove the keyboard and mouse pad, actually attach a plate and create the ultimate CarPC case. Imagine a CarPC around the size of a thick magazine, install possibilities are widely expanded when a laptop motherboard is chosen. Very unconventional locations can be used with ease. The plate can be the mounting system and brackets can easily be extended off of this plate even before the plate is attached to the lower half of the laptop. A laptop like this can be installed under a dashboard or sometimes behind the glove compartment, in a center console sometimes, ahead of the shifter, sometimes directly in the dash, if you're creative there are other more far out possibilities, like in a headliner or seatback, of course this can also be installed in the trunk too. You should pay attention to airflow and make sure there is enough for the machine you choose.



Laptop, screen and all



There has always been interest in using a laptop screen for a CarPC. Well the absolute BEST way to use a laptop screen is to run it off of the laptop it came with. One major problem with this approach is most laptop screens are not very bright at all and will suffer in the daylight even more than the typical Lilli’s and Xenarcs and really be pretty useless for daytime bright sun use, but, there are exceptions.



A completely integrated and efficient install can be created by embedding an indoor/outdoor screened tablet in your dash, considering the single tablet will include your whole carpc including a transflective screen, motherboard, memory ram and hard drive and operating system this can actually be a pretty cost effective solution too, or at least on par with the alternatives.



This option may work well for those desiring screens of 10.4” and larger, but now even smaller screens are surfacing, like Fujitsu’s new 8.9” widescreen indoor/outdoor tablet. Virtually everything you need for an awesome carpc can be had from one of these tablets, right down to the touch screen and all, but it also is not for everyone to disassemble and install an expensive delicate and beautiful machine such as this, but the end result could be spectacular.



One major problem area in the “screen run off the laptop board” approach is dealing with the ribbon cable, these can be anywhere from not too difficult to totally impossible depending on the actual cable design, but if you're determined enough even an impossible to extend ribbon can be dealt with. Sometimes you may have to have a harness made for you, but there is almost always a solution.



Choosing a Tablet as a CarPC



Using a tablet as a CarPC is a somewhat newer subject and there is far less information available than for other devices, but people have started doing so.
There are many tablets to choose from and hardware varies a great deal:
* some are cheap and the screens do not have very good daylight visibility
* most do not have FM receivers
* many do not have 3g data, just WiFi

Choose carefully!

I will speak from experience for the rest of this post and welcome edits as those with more information choose to add it.

Barnes and Noble Nook Color
I am using a removable Nook Color which has been rooted and runs CyanogenMod 7 (nightly): this adds Bluetooth, overclocking and far more control of the device than the stock operating system. (Note that CM7 is under very active development on the NC and changes most days as of 29 March 2011.)

For Navigation I use a Droid cell phone with Wireless Tether for data and TetherGPS for GPS location on the Nook Color's 7" screen.
For music there is a headphone jack which can be connected to a headunit's aux jack or to amp inputs. (Not yet tested)
*Streaming music over bluetooth may also be possible but note that the Nook Color bluetooth has very short range. Other devices may not have this limitation.

There are quite a few car-oriented applications available in the Android Market and one may suit your needs. The interface itself is already more car-friendly than Windows or Linux, being based on cell phones, and Honeycomb (and CyanogenMod 7) will be more so once it is widely available.

The Nook Color is a good choice NOW for a CarPC that is, admittedly, limited to fairly basic desires, but the near future should see it extended to be even more versatile, especially if a removable device is desired.

Android tablets in general are an excellent choice but use care when selecting one! Most of the inexpensive ones do NOT have good screens and may not have a strong developer community improving them beyond the manufacturer's intentions.