Transport buses worldwide typically may use an ARM-based platform to provide limited infotainment applications to riders, such as arrival stops and schedule, or some ads. To give riders more entertainment and information, China's Bus Online provides television networking in transit buses to broadcast commercials, TV programs, and short movies for a less boring passenger experience.
To enable such connectivity in a demanding transportation environment, Norco, a maker of embedded computing boards, developed its CBP-3000 in-vehicle computing system as an intelligent network control for functional flexibility. The system is an X86 platform based on the Intel® Cedar Trail AtomTM processor N2800/D2700/D2500 low-power embedded CPU for high computing power, multiple I/O, and low-noise operation. Besides entertainment, the CBP-3000 can serve the practical uses of bus surveillance, vehicle systems monitoring and displays, navigation, and WiFi and Internet connectivity. And other transportation applications include taxis, emergency response vehicles, fleet vehicles, trucks, and trains.
Design challenges and enablers
Design engineers had to provide ruggedness, including vibration resistance, in the system and a wide temperature operating range to handle the transit bus environment. Transportation vibrations are characterized by large amplitudes in any direction. Thus features such as "air-tight" pin connections, guide pins, and all-around damping material are incorporated into the modular design. Spring isolators are introduced if a given system will use a hard disk drive. Thus the CBP-3000 design meets ISO-16750-3-2003 for vibration. In addition, double-layer seals and multiple coatings guard against moister intrusion—including the effects from washing the vehicle.
In any transportation application, vehicle electrical power quality affects the stability of all electrical devices onboard. The power and other modules in the CBP-3000 system must handle a variety of transients and interference possible during bus operations. Thus electrical power provisions for the in-vehicle computing system incorporate under-voltage, overload, over-current, over-temperature, load-dump (vehicle battery disconnect), and short circuit protection.
Examples of such electrical transient upset occurrences include:
- A pulse caused by disconnection of a DC supply through an inductive load, such as a windshield wiper motor
- When the ignition is switched off, DC motors may act as pulse generators.
- When automotive electrical switches and relays are cycled on or off, voltaic arcing can cause transients.
- Activating an internal combustion engine starter motor or turning on the air conditioning system compressor can cause a system voltage drop.
- The previously mentioned electrical system "load dump" transient (voltage pulse) can occur when a discharging battery is disconnected while the alternator is generating a charging current with other loads still on the circuit. A battery cable can be disconnected because of an inadequately tightened connection, corrosion in a cable or fitting forming an open circuit, or deliberate disconnection or inadvertent fusing of the battery while the vehicle is undergoing maintenance.
To accommodate such challenges as noted above, the CBP-3000 design meets ISO-7637-2-204 for electrical power systems quality and ruggedness.
The Atom processor has another design benefit for the CBP-3000. Vehicle applications can have a wide temperature range, including the influence of direct solar radiation, producing temperatures up to 70°C. The processor's high conversion efficiency and inherent low power cuts heat generation so much so that only convection cooling is needed. The temperature range of the CBP-3000 goes as low as -30°C.
The in-vehicle computing system is a modular design that utilizes an "industrial grade" chassis for surviving the rugged bus transportation environment. For system flexibility with the potential for change and expansion, all modules load into the front of the chassis (and have front-facing connection provisions) and are interchangeable in each slot. This kind of accessibility and connectivity also eases trouble shooting and maintenance.
- Power module: Voltage input ranges from 8 to 36V with total power provision up to 150W, and includes transient protection as well as reverse-polarity protection; under-voltage threshold = 7V and over-voltage threshold = 80V; optional UPS provision; provides software compiler interface
- Vehicle amplifier: Supports up to four stereo inputs in priority order with power up to 40W, normally off and automatically on with power activation
- Vehicle server: Intel Atom processor with Intel NM10 chipset with up to 4G DDR3 RAM plus RJ45 debug port and 1 Gbit Ethernet port connected to switch module via backplane
- Switch module: Integrated WiFi support for up to 50 users online (with one minute delay when powering down), eight adaptive Ethernet ports
- Vehicle media player: Intel Atom processor with Intel NM10 chipset with up to 4G DDR3 RAM, twin mini-PCIE for 3G and WiFi support
The CBP-3000's low-power Intel Atom CPUs, compact modular design for installation flexibility, access and maintenance ease, and UPS power availability also contribute to shorter time-to-market and lower overall costs for space-limited vehicle applications.
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Norco-Habey is an Associate member of the Intel Intelligent Systems Alliance.
Roving Reporter (Intel® Contractor), Intel® Intelligent Systems Alliance
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