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Design case study I Defence & Obsolescence


speed. Providing heat dissipation is a source of considerable expense. Designs must channel heat away from the processor, or else it will suffer thermal shutdown.With a wearable computer, the user’s thermal environment changes routinely. In the environments targeted by Quantum3D, the typical mounting is on the soldier’s back. Here the challenges are about ambient temperature and the use of the system in hot desert environments, possibly in sunlight and also in cold tundra environments. A man-wearable system must deal with both. Heat dissipation in hot environments – extracting heat from the inside to the outside where it can dissipate – is critical. Careful use of resources helps avoid many heat-generation crises for a wearable computer. For example, developers could write applications for wearable computers with heat dissipation in mind. The computer can delay disk maintenance, downloads and batch jobs until it senses a cooler environment. Depending on perceived user need, a slower network connection might be appropriate to allow more time for heat dissipation. With such methods, performance is reserved for user interactions, and the effective average power consumption can be higher without causing uncomfortable spikes in heat generation.


Solution integration


Quantum3D had several options available to it to meet these design requirements: design a computing platform from scratch; use commercially available modules; or work with a combination of the two. Designing from scratch is laden with risk; time-to-market, design expertise, life-cycle management and many other issues. While designing exactly what was needed was achievable, the time to do so would have taken more resources and more time than was available. To use off-the-shelf modules would eliminate many of those risks, but their particular design goals had requirements not typically found in commercial solutions. The unique requirements for mobility and I/O devices placed a lot of constraints on what could be used.


The best alternative integrated a combination of internal design and commercial modules. Quantum3D had design teams dedicated to the development of the I/O, communications and human interfaces. Processing elements were best supplied by readily available commercial modules – all that was needed was a way to merge the two together. To do that, Quantum3D engaged with Connect Tech for an exact-fit customised solution. Connect Tech leveraged its expertise in computer-on-module (COM) carrier board design based on standard and embedded form factors such as PC/104 and PCI Express, and this was combined with a Qseven style processor module from congatec.


The Qseven concept The Qseven computer-on-module concept is an off-the-shelf, multi-vendor COM that integrates all the core components of a common PC and is mounted onto an application-specific carrier board. Qseven modules have a standardised form factor of 70mm x 70mm and have specified pin- outs utilising a low-cost, high-speed MXM connector system with a standardised pin- out. A single ruggedized MXM connector


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provides the carrier board interface to carry all the I/O signals to and from the Qseven module.


The key advantages to Qseven modules


are their small form factor, range of current processor options and multi-vendor sources. Qseven COMs are some of the smallest, full-function COMs on the market, making them very attractive for embedded mobile and ultra-mobile applications. Connect Tech designers were able to


utilise precisely the I/O interfaces required by Quantum3D. The carrier board provided all the interface connectors required to attach the system to the Quantum3D application-specific peripherals.


Combined solution


The depth of choice is a critical criterion for many system designers. Often designers have constraints they cannot control or they may need the flexibility to make choices later in the design cycle to accommodate changing requirements during development. The combination of COM, carrier and custom I/O gives designers options that can benefit them throughout the entire design process. Scalability: Applications are scalable, which means once a product has been created there is the ability to diversify the product range with different performance class Qseven modules and I/O payloads through the carrier module. Simply unplug one module and replace it with another; no redesign is necessary. Upgrades: Processor technology moves very quickly, with enhancements to existing processor families occurring two or three times a year. Compounding the problem are the numerous new processors introduced every year. Having the processing element, memory and supporting chipsets on a COM enables using the newest technology and then moving it into the product line at the right time. Because PCI Express is the common denominator, many cross-platform processor choices are available if needed. Instant upgrades to existing products can be offered and the product is never trapped in an obsolete design. Cost: System cost can be reduced in lower unit volume applications by using high-volume components such as Qseven COMs. COM suppliers can increase unit volumes and reduce part numbers, generating savings that can be passed onto the integrators.


Quantum3D designers met the 40


percent improvement in battery life goal without giving up key features and performance needs. In addition, trade-offs were minimal with the combination selected by the Quantum3D design team. Connect Tech’s Qseven carrier combined with the congatec Qseven COM met all of the feature requirements. The Intel Atom processor met the low-power requirement, and the open-architecture, modular structure provided an upgrade path and scalability to add additional features now and in the future.


Congatec | www.congatec.com Connect Tech | www.connecttech.com Quantum3D | www.quantum3d.com


Patrick Dietrich is a hardware design engineer and project manager with Connect Tech.


Components in Electronics March 2012 21


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