Choosing and configuring an In-Vehicle computer system is no simple task. Mobile digital signage, fleet management, automated traffic control, and surveillance — just to name a few popular in-vehicle applications — require vastly different specs. Adding to the complexity, the In-Vehicle environment has its own challenges, including power, temperature, and vibration. Here are some questions you should ask yourself to get the required development and prototyping process started.
First off, why do I want a PC in a vehicle?
With the options like tablets, smartphones, and in car docking stations for laptops, you need to ask yourself, “Do I need an In-Vehicle PC in the first place?” The answer is definitely situational.
If you are changing vehicles all the time and need a device that travels with you, the answer is no. But if you are in a dedicated vehicle where the machine needs to run a single purpose application; where you want to have a hassle free integrated power solution; or where you need the computer to integrate into some system on the vehicle? Well then the answer is yes.
Over all, In-Vehicle systems include components that are well suited to a mobile environment where shock, vibration, power, and temperature fluctuations are par for the course.
What kind of processing power and I/O do I need?
If you have settled on using an In-Vehicle PC, the next questions involve processing power and Input/Output (I/O). Of course, your decision whether to use Atom, Core i, Celeron or a Haswell-based system is largely a function of your application needs. But keep in mind that processors generate heat (see section on temperature below) and you will likely want to use the lowest TDP your software will allow.
Next take a moment to consider your I/O. Not just in terms of what various peripheral devices you need plugged in, but also what devices might travel. Generally speaking the backplate’s I/O is for peripherals that are always plugged in, while the front is for traveling devices. This is often a factor when the system is mounted on a dash or a console. Think through how many USB ports you might need with easy access, if you need COM, or HDMI or what have you. Accessibility of I/O is just as important as it’s presence.
Finally, antennae are often overlooked, but how your vehicle connects to other vehicles, networks, GPS, Wifi, BlueTooth or the like is a crucial part of the system. Extending the range with antennae is often a must have. Moreover, multiple antennas will allow for simultaneous usage of different connectivity, such as if you need Wifi and GPS, or you can dedicate one antenna to broadcast and another to receive, increasing the traffic flow. Assessing your communication standard is a key part not to be forgotten.
How do I deal with shock/ vibration and dust?
Most systems are cooled by processor/motherboard fans and case fans. Movement, in particular sharp shocking jolts common in automotive vehicles, can damage the very thing keeping the system from overheating. Fanless systems, by contrast, use passive cooling technology like heat sinks and heat vents to remove the need for such a vibration-sensitive component. Moreover, because the fan is gone, the system no longer sucks in air and with it dirt, dust, and sand. If the PC is exposed directly to that dirt and dust, you will want to make certain your fanless case is fully enclosed, not perforated/vented. A fanless vented case may not draw dust in with fans and helps with cooling, but it won’t prevent dust from settling and corroding the electronics either, whereas a ventless enclosed case will.
To truly proof against vibration, you will want to eliminate the spinning hard drive and use a solid-state drive (SSD). On a train, for example, it’s vibration that is the killer. The constant motion of the train doesn’t seem like it would be bad, but on moving parts in a PC it can be hell on hard drives. There are a number of rugged options, but in the case of major vibration SSD is the way to go. They have no moving mechanical components, where as standard hard drives (HDDs) contain spinning electro mechanical magnetic disks to store data, movable read/write heads to read and write it, and motors to run the whole thing. A SSD, by contrast, uses integrated circuit assemblies as memory to store the data persistently, making it faster, quieter, and resistant to vibration. When vibration is a factor, SSDs are a must.
What kind of operating temperature range do I need in my in-vehicle PC?
Frequently, the mobile environment heats up. If you expect your system to be operating in environments above 29°C, you will want to take care to select a SFF board, case and components that can handle the heat or consider fanned systems. If you must use a fan, you will need to install the system in a way that allows the case fan to vent properly. Failure to do so will cause the system to overheat and fail.
In extreme temperatures, hot or cold, focus on maximum and minimum operating temperatures. Motherboard choice, cooling, wifi, and storage components will all influence operating temperature. Your average SSD hard drive is pretty solid in most environments, but sub-zero and over 40°C can tank the performance of drives. Extreme environment hard drives are recommended and have a wider operating temperature. They should be considered along with board and case fans if you need to beat the heat.
Notice the contradiction with the advice above? To deal with shock and dust, go fanless. To deal with heat, fans work well. You may need to prioritize your needs and make tradeoffs. You can also search for fanless units with wide operating temperatures. Remember, you can get a fanless unit with a wide operating temperature and good processing power. But you can’t get all three and not pay for it.
Power: The bogeyman of automotive PCs
In cars, trucks, and busses it’s often power that flummoxes things. In contrast to most computing environments, transportation PCs are dealing with fluctuating DC current. Under normal conditions, battery voltage in vehicles can fluctuate between 11 and 14 volts. For that to power a small form factor system, it requires at least 2 elements: A regulator to provide a stable 12 volts to the external computer system and a DC-DC converter to provide the DC voltage rails required by the motherboard. You also might want an Intelligent Power Supply, an option that allows your PC to use the car battery, but nevertheless safely shut down or keep it running when the car or truck is turned off. This is important for the longevity of your PC.
Cars, trucks, planes, boats and trains: where is it going?
Boats, airplanes, cars, trains and the like all have their own issues. Unique environmental concerns, space requirements, weight requirements, and more. The big concerns are what is the PC going to be exposed to in your environment, what’s going to be in the PC and where is it going to be on the vehicle. Stop and really consider the environment for what it is, and the dangers it poses to your system.
There are many other concerns that can come up when dealing with automotive PCs, and this is just a good conversation starter. If you have any questions, feel free to comment below or visit our transportation page. When in doubt, consult a professional.