Portable devices are those intended to be moved regularly, but not necessarily for handheld use. Portable device design yields rugged packaging, a relatively compact and lightweight device, and sometimes battery operation or battery back-up.

Handheld devices are typically used while being held. Handheld device design must ensure that the device can be comfortably held by a person, and has a number of added constraints: very lightweight, intuitive and ergonomic to use, easily read display, button presses and touchscreen use must not be fatiguing, usually battery operated, can’t get too warm to hold, and more.

Tablet

Successful portable and handheld device design requires careful optimization of electronic, mechanical, and thermal design:

  • Selection of a low power, high performance, long availability embedded processor
  • Circuit customization to accommodate low power and power saving modes
  • Tweaking of operating system behavior to match the circuitry
  • Design of a lightweight but rugged enclosure that protects all controls and the display, often watertight
  • Development of ergonomic packaging and user controls, which may include thumbsticks, buttons, dials, and a touchscreen
  • Specification of a battery with the capacity to provide run time targets without being too heavy
  • Manage internally generated heat in an unventilated package
  • Provide an acceptable price while meeting production longevity targets

Tablet design is a subset of handheld device design, where the overall device is very flat and the majority of the device front contains a touchscreen display.

The combination of these factors makes the design of portable and handheld electronics a niche area of expertise.

To maximize success with minimal cost, short schedules, and low risk, a system engineering approach analyzes use cases and specifications. Tradeoffs between hardware, software, and packaging implementation have a huge impact on the technical, financial, and production success of the product.

  • Low power design: selection of low power components, weigh power vs performance, power-optimized circuitry, power gating, power/battery lifetime modeling
  • Small footprint design: high component feature density, dense but robust PCB routing
  • External interfaces: wireless and wired connections to networks, sensors, and peripherals
  • Displays/touchscreens: based on human requirements. Includes sunlight and night readability, gloved touch, etc.
  • Rugged design: packaging for drop, shock, vibration, moisture, dust, extreme environments.Industrial design for look, feel, and ergonomics
  • Operating systems: Linux, Android, Windows, VxWorks, other RTOS. Optimize boot loader, BIOS, kernel, drivers for user application support and power efficiency
  • Security: mechanical, hardware, and software level security to control access, detect intrusions, and secure the device upon detection
  • Remote device management: software updates (controlled by the customer), tracking, health monitoring