Useful Technology for your Idea File

Resistive Mouse: The contoured bottom of the actuator (joystick button) conducts compressive forces into the resistive pad that forms a bridge circuit using quarter-sections of the circular area for directional output.

Mini mouse uses resistance bridging

This 9-mm-square, 360-degree OEM cursor control replaces arrow keys for use in cell phones and other hand-held devices. Depending on the height of the actuator assembly used, joystick versions of the MicroNavTM can stand from 3.5 to 9 mm above the printed circuit board it is mounted on.

Key to the design is the patented circular Force Sensing Resistor (FSR®**REGISTERMARK**) pad. The curved bottom of the actuator above the pad transmits finger force into it. The FSR is a polymer thick film (PTF) device, which exhibits a decrease in resistance with an increase in the force applied to the active surface. Behavior is similar to load cells or strain gauges but at a lower cost, says Keith Roberts, director of corporate communications. That savings comes about from the resistive material being printable and easy to apply.

As the base of the joystick is pressed and "rolled" over the circular pad of the FSR, the pressure varies the grounding of the resistive material beneath it. Forces and their location on the four wedge-shaped quarter sections of the area (which form the bridge circuit's resistors) provide position and velocity information from the voltage output.

The sensor is reportedly good for more than 10 million actuations and is reflow compatible for automated assembly. Future uses of FSR technology could combine pressure (position), time, and speed-of-stroke measurement for handwriting recognition.

Contact:Bruce Pocock, Interlink Electronics Inc. Tel (805) 484-1331; Fax (805) 484-5997; e-mail: bpocock@interlinkelec.comhttp://rbi.ims.ca/3846-500

Back Office: With a controller integrated within the back of the motor, the SilverPak allows for quicker implementation of stepper motor systems.

Integrated controller simplifies stepper use

By integrating a controller within the housing of the SilverPak 17, a 1.8-degree step motor, driver, and controller package, engineers provided for quick installation and set up. Motion commands can be input from any serial terminal program, such as HyperTerminal or from the SilverPak Windows®**REGISTERMARK** application, by way of the onboard RS232C or RS485 bus. The bus can connect up to 15 step motors. The package can operate in a standalone mode with no connection to a PC using a preset string of commands upon power-up.

Simplicity of use is the key in producing a package aimed at the low-end market of simple motion and moves, notes Director of Sales Ryan Lin. Point-to-point move applications without encoder feedback are easily set up using a one-letter, command-type structure.

The package provides trajectory motion, two digital I/O channels, two fixed I/O channels, preset motor winding current levels, and safety stop orders. Commands include nested loops and execution-halt pending a switch closure. The size 17, step-motor module is also available with Cavro DT and OEM medical communication protocols. The 17D version comes with driver only.

Modules come with holding torques, in a bipolar drive mode, ranging from 30 to 83 oz-inches, depending on stack length. The motors can be stepped at 400, 800, and 1,600 steps per revolution. Power and control inputs are via a 9-pin DB-9 male connector. A designer's kit with components and software for a test installation is also available and other frame sizes are planned for introduction later this year.

Contact:Ryan Lin, Lin Engineering Tel (408) 919-0200 x214; Fax (408) 919-0201; e-mail: rlin@linengineering.comhttp://rbi.ims.ca/3846-501

Interruption: When a conductive object, such as a finger, interrupts the electric filed between sensor electrodes, an active ASIC detects the change and outputs a digital signal in 160 microseconds.

Field-effect sensor offers sealed, long-life operation

The patented MirusTM detector cell uses field-effect technology to allow finger activation through a wide variety of sealed, protective surfaces, including plastic, glass, wood, or isolated metal. And with flex circuits instead of printed circuit boards, such interface controls can be placed on curved surfaces.

Without any moving parts for long life, the sensor uses two electrodes, one surrounding the other on the surface, and an adjacent, active ASIC. The active chip drives the two electrodes with an oscillating electric field, generating an electric field around the cell. When a stimulus, such as a finger, interrupts the center of the field, the ASIC detects the break and generates a digital signal output. A stimulus covering both electrodes, a layer of contaminants for instance, is rejected by the ASIC and there is no response. Electrode configuration, circuit gain, and ASIC programming govern sensitivity—which allows company application engineers to design the cells to meet customer-specific needs.

Placing the ASIC close to the electrodes is key to eliminating problems that can be found in touch sensors, says Mike Taylor, director of product and process development. This arrangement provides a high signal-to-noise ratio resulting in the sensor not being susceptible to changes in the environment. This configuration also has a low impedance to ground (in the low kohm range as opposed to Mohms for capacitive touch sensors), which increases immunity to induced electrical noise.

Another benefit of the dual-electrode structure is that the electric field is much more pronounced within the cells than between them—mitigating cross talk between adjacent touch cells. And strings of Mirus cells mounted on tanks can be used to determine liquid levels.

Contact:Mike Taylor, Material Sciences Corp., Electronic Materials and Devices Group, Inc., Tel/Fax (616) 915-6024; e-mail: michael.j.taylor.emd@matsci.comhttp://rbi.ims.ca/3846-502

Cushioning the Load: Multiple structural members used in the Advanced Compatibility Engineering configuration at the front of a vehicle absorb greater loads with the engine compartment structure. These also prevent misalignment with the frames of other vehicles in collisions.

Structure spreads loads

To further protect a vehicle's occupants and reduce damage to other vehicles and injuries to their passengers during collisions, Honda engineers have developed the Advanced Compatibility Engineering body structure. Injuries and fatalities arising from collisions between vehicles of different sizes, specifically involving SUVs or pickup trucks, led to the collision-compatibility requirement.

The body architecture is the latest iteration of the company's G-Force Control collision safety technology. A new front-end frame structure, roughly forming an energy-dissipating cage around the engine compartment, reduces the concentrated force of an impact by dispersing and absorbing crash energy over a larger structure. Another key feature of the configuration is that it does not easily become misaligned laterally or vertically with the frame of another vehicle, mitigating potential injury to all occupants. A bulkhead (upper frame) absorbs the upper collision impact and a lower member mitigates frame misalignment.

The Advanced Compatibility Engineering structure is now in production on the Japanese-market Honda Life minicar. The configuration will be used on all new Honda vehicles over the next six to seven years, which in the US starts with the 2005 Odyssey minivan and Acura RL sedan. The Life reportedly demonstrates 50 percent better collision energy absorption by the engine compartment while reducing passenger cabin load by 30 percent.

Contact:American Honda Motor Co. Tel (310) 783-3170; Fax (310) 783-3622 http://rbi.ims.ca/3846-503