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Maximizing Hardware & Software Selections for Advanced Touch Screen Applications

Maximizing Hardware & Software Selections for Advanced Touch Screen Applications. Michael Woolstrum CEO , Touch International. We Will Answer. What hardware issues do I need to be aware of prior to designing a touch screen device?

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Maximizing Hardware & Software Selections for Advanced Touch Screen Applications

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  1. Maximizing Hardware & Software Selections for Advanced Touch Screen Applications Michael WoolstrumCEO, Touch International

  2. We Will Answer • What hardware issues do I need to be aware of prior to designing a touch screen device? • How do my hardware choices affect software development and system performance? • Topics Covered: • Touch Product Design Considerations • Touch Technology Issues • Designing for High-Performance • Touch Screen Tail Design • Choosing the Right Interface • Touch Screen Electronics • Tuning, Firmware & Calibration

  3. Design Considerations When designing a unit, consider: • Size of display and overall system size • How you want touch screen to look and function • Application • Time to market • Environment • Industry regulations • Cost

  4. Display Considerations Key LCD Considerations • LCD lifespan is short – 3 years is common • No standard dimensions – 7” is most standard size • Select narrower borders for flush finish • Design bezel and touch screen for LCD changes • Does application require high-bright, high/low temp, high light transmission, or sealable LCD? • Is LCDeasily acquired? • Cost

  5. Touch Technology Determine Touch Technology • Things to consider: • Application • Environment • Availability • Cost • Also consider • Difficulty to manufacture (complexity) • Touch input method (finger, pen, glove) • How long does touch screen need to last?

  6. Touch Technology Issues Projected Capacitive for iPhone Experience • Custom designs often very complex • Higher cost compared to resistive • False touches possible • Tuning required • Prone to noise interference – may require EMI shielding • Multiple input methods dependent upon tuning • Sensitive to water • Integration can be complex

  7. Touch Screen Integration Typical Projected Capacitive Touch Screen Integration Add back housing to graphic

  8. Touch Technology Issues Resistive for Low Cost • Moving parts make resistive not as durable • Cover glass is not typically an option • Requires input pressure • Periodic recalibration • Lower optics • Requires bezel around touch screen • Not the “look” that many expect today

  9. Touch Technology Issues Optical for Large Format • Occlusion (line of sight) problems when light path is blocked • Subject to interference from other light sources or reflections • Thicker bezel needed to hide IR cameras (3mm for 19” screen) • Possibility of false touches • Susceptible to ghosting

  10. Touch Screen Integration

  11. Designing for High-Performance Meeting Industry Regulations with Display Enhancements • Adding display enhancements to touch can correct many environmental and regulatory issues. • Military, Medical, Aerospace Industries – many requirements • Aerospace – HIC Compliant, Self Extinguishing, Low Toxicity • Military - NVIS compliant, EMI shielding, high-temperature tolerant • Medical - NEMA sealable, anti-microbial, shatterproof

  12. Display Enhancements Military Application Requirements • Extreme Outdoor Environments • Advanced Sunlight Readability • Optimized Video & Light Images • NVIS (Night Vision Imaging System) Compliant

  13. Tail Design • Key component to getting touch screen right • Consider how much room tail has and placement of it • Bending tail can damage communication • Chip-on-Flex • Only available for projected capacitive • Allows for tail to be long and far away from electronics • Minimizes noise and interference • Entire sensor scrapped if chip needs to be replaced • Chip-on-flex is expensive

  14. Choosing the Interface Method • I2C • USB • Projected capacitive accepts any interface method • Resistive requires USB or RS232 • Optical usually USB HID • Motherboard input type often plays role in choosing interface method. • Off-the-shelf unit (lowest cost) limits interface flexibility • In-house design (expensive) allows for all options • USB HID • Serial (RS232) • Serial HID • USB-UART

  15. Touch Screen Electronics Touch screen performance controlled by controller • Converts electronic signal sent from touch sensor to the host PC through a I2C, serialor USB interface in an X/Y format. • Two Types • PCB (traditional controller board) • Chip-on-Flex

  16. Touch Screen Electronics PCAP Controller Challenges • False touch • Subject to EMI noise • Cost can be very expensive depending on capabilities • If slim design/space constraints, then chip-on-flex • Custom firmware required for PCAP

  17. Touch Screen Electronics Resistive Controllers • No real challenges with resistive electronics • Traditional resistive controller (4, 5, 8-wire) very low cost • Multi-touch resistive controllers are expensive • Chip-on-flex not an option (also not needed) • Easy to integrate or replace Optical Controllers • Any issues with them?

  18. Firmware/Drivers/Calibration Insert Graphic

  19. Firmware/Drivers/Calibration Firmware • Tells touch screen what kind of touches or input to pay attention to or ignore • Can make touches more or less sensitive (application specific) • Provides system level EMI shielding Drivers • Mainstream OS drivers loaded on chip • Customer must write own drivers for custom OS

  20. Firmware/Drivers/Calibration Drivers • Mainstream OS (Windows 7) drivers loaded on chip • Android, Linux drivers usually available from chip manufacturer • Customer must write own drivers for custom OS Calibration • Projected Capacitive, Optical, MARS - one time calibration • Analog Resistive – periodic calibration

  21. Software Selections for Advanced Touch Screen Applications Jeff Carpenter CEO, Ringtail Design

  22. What We Will Cover • What are the advantages and limitations of software tools used to develop touch applications? • How to choose the best software development method for interactive platforms See word document for software section outline.

  23. Operating Systems Windows 7 • Industry standard touch screen platform • Supports multi-touch • Plug and play – does not require additional drivers Android • Supports native multi-touch • Additional drivers needed to run touch screen

  24. Operating Systems Linux • Supports native multi-touch • Additional drivers needed to run touch screen iOS/Leopard • Supports native multi-touch • Additional drivers needed to run touch screen All operating systems available as embedded O/S

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