PC Peripherals

Hello and welcome back to my blog on building a custom in car computer. In the previous posts I discussed in detail how I designed and built a custom made console to house the miniature PC that I will be installing in my 4X4. I ran into some cooling issues on the way but I have taken measures to mitigate these problems. So, let the build continue!

So to meet the requirements I set in the first post, The PC needs to be able to have certain functionality added to it including:

• -Display: Wile I used a desktop monitor for the initial testing, the PC will need a fixed monitor that meets the requirements for in car use, more on that later.
• -Input: Obviously a mouse and keyboard are impractical and unsafe for use in a vehicle, so a touch-screen will be required.
• -GPS: The PC needs to know where it is in order to run navigation software
• -Radio: A FM radio receiver will be required so I can listen to my favourite radio station while I drive
• -Internet: A high speed internet system will be required with high gain antennas to get mobile internet on the go. 
• -Engine diagnostics: A module that plugs into the vehicle's OBD II port to read in real time engine statistics and clear fault codes. 
• -Additional media controls (volume, play/pause, next/prev ect): For ease of use while driving.

First thing's first, in order to be able to use the computer, it will need a screen. However, there are several requirements that it has to meet in order to be practical for use in the car. They are:

• Automatic brightness control. The screen must be able to adjust its brightness either based on the ambient light around it (Similar to what most smartphones and tablets do automatically), or have a dimming feature activated by turning the vehicle's park lights on (like most automotive head units) This is both a convenience and a safety feature as a screen that is too bright at night will disrupt night vision, and a screen that is too dim during the day is just plain annoying and hard to read. 
• Capacitive touch input: This is a personal requirement, as capacative touch screen technology (Commonly found in all reputable branded smartphones and tablets) is far superior to resistive touchscreen technology. Not only does it provide much smoother and more responsive use, it allow for better screen viewing angles, multitouch and a glass coating that can be layered over the top for extra durability.
• Automatic power on: The screen needs to turn on and automatically switch to the correct input channel when it receives power. 
• Sufficient brightness for daylight use
• Size - the screen is not too large or too small for the car's DIN bezel (By my measurements the active screen size has to be between 165-205mm  [6.5-8"] diagonal as the bezel can be cut to allow for a bigger screen)
• Anti glare coating for easier readability in sunlight
• Wide operating voltage range (roughly 10-18 volts to allow for voltage dips and surges)
• Wide operating temperature range (roughly 10-50 degrees Celsius)

You will notice that many pf the main requirements listed above involve automation of some sort. I am a believer of the philosophy that automation improves safety by removing human error. During the planning and building of the computer system I have sought to include as much automation as possible with the exception of safety and redundancy (backup) features. This also makes my life easier as the end user of the system as it means I can focus more on driving the car and less on using the computer. 

The screen I chose that meets all of these requirements is the Xenarc 700CSH. This screen (while ludicrously expensive) is a solid industrial grade unit that supports touchscreen control VIA usb and has acceptable resolution for its size. After all, the screen is the component of this build that I will see and use the most. 

With the display and input requirements covered, it's time for the GPS:

I chose the latest and greatest in GPS technology, the BU353S4 (Which I have now received from the mail). This compact unit is not only IP rated to be splash-proof and dust proof, it has a handy magnetic base for attaching to ferrous surfaces (It conveniently sticks to the steel bracket built into the front of the roof console). Performance wise, it has the latest SiRF star IV GPS chipset at its core which is more than surplus to requirements for my needs. 

For the FM radio I chose a cheap and cheerful RTL232U based FM radio+ DAB USBdongle. This unit supports digital TV and radio as well, but as it turns out finding a FM-only dongle these days is almost impossible. I will need to find a way to adapt the external antenna plug on the dongle to my vehicle's coaxial plug to use it with the existing FM antenna later on. 

I still have not decided on a mobile internet router, as I will need to so some research on which system with which carrier will provide the best coverage at the best price. Until I decide on a solution I will use the hotspot feature on my smartphone. More on that in future posts.

I have plans to upgrade the PC later on with other peripherals, such as USB HD video cameras for 24/7 security/dashcam recording and a dynamic control system for on-board lighting systems. These systems will be fitted at a later date; right now I'm focusing on getting the car pc with the original requirements running perfectly.

As for the engine diagnostics, I have had no luck in the past trying to read fault codes from my vehicle's ECU. This is due to Nissan using a proprietary interface system known as Consult, which requires special licences and hardware to use. I am currently working around this problem and will post updates in the future. This peripheral system may stay on hold as I have plans in the works to re-power the vehicle with a different engine, which will use a different ECU and hopefully the standard OBDII protocols.

**Update 26/9/15**
I have integrated engine diagnostics into the computer, see posts #15 & 16.   

That's it for now, The next post should include the installation of the extra switch holder, the boxing up and re-installing of the computer into the vehicle and the planning and installation of the monitor into the car. I know this post probably wan't as interesting as the other ones (it certainly wasn't as illustrated), but more photos will come. Goodbye and thanks for reading.