The toothbrush turns on.
The toothbrush turns off. How can you improve on a control like as
Today's aggressive suppliers
of sensors and controls might come up with a dozen ways of making that
simple On-Off component better.
For example, MEDER
electronic Inc. (Mashpee MA, U.S.). saw plenty of room
for improvement in the simple slide switch often used in this application.
Such a control, the company points out, has the potential to become
contaminated quickly and ultimately corrode. After all, a toothbrush
may be exposed to acidic human saliva, alkaline toothpaste, and
water temperature extremes. Corrosion may cause faulty switching,
resulting in a dissatisfied customers. After all, most users expect
their electric toothbrushes to last for years.
MEDER notes that hermetically
sealing the slide switch can be an expensive solution, explaining that
the reed switch/magnet combination is being recognized more as an option
in such applications. This control uses a magnet molded into a plastic
sliding configuration. Sealed inside the electric toothbrush, mounted
on a p.c. board, the reed switch senses the position of the magnet.
This provides a sealed control system that enables a toothbrush to
operate for years, just as the consumer expects it will.
a flat ceramic cooktop that senses when liquids boil over and in
response reduces or turns off the heat automatically. That's a potential
application with the MC 33974 electric field image sensing IC from Motorola (Austin,
TX, U.S.). the IC generates and detects a low-level electric field
and powers and supports a microcontroller unit (MCU), all in a single
chip. It is designed to replace numerous discrete devices previously
needed to achieve the same functionality. Target applications of
the IC (imaging sensor) include appliances, machine tools, and virtually
any other product or system that uses touch panel inputs as a user
interface. Motorola says applications such as liquid level detection,
spill detection, or moisture sensing would be simple to implement.
Distress in the global economy
has increased cost pressures on the appliance industry. Recent years
have seen costs, always a high priority, become even more of a focus
for the industry, and that naturally cascades down to suppliers.
“Yet at the same time
appliance makers are requiring their components to be continually improved
in terms of performance, reliability, and space savings. Sometimes it’s
a trade-off,” says Gordon Swanson, controls engineering manager
for Kidde-Fenwal in
Ashland, MA, U.S.
There’s also the problem
of heightening buyer expectations. Consumers see their PCs and their
mobile phones come down in price and expand their capabilities every
year, and expect appliances to do the same.
“Consumers are very savvy
and demand more features at a reduced cost,” says Stephen Caldwell,
director of the Home Appliance Solutions Group for Microchip
Technology (Chandler, AZ, U.S.).
In the controls arena, the
costs per component are indeed coming down even as the technology grows
more sophisticated. This is especially true in the electronic controls
arena, notes Mr. Swanson of Kidde-Fenwal. “Not only is the per-part
cost dropping, but so are the indirect costs—as an appliance company
can save significant support expense by using digital technology instead
electronic’s reed switch/magnet combination uses a
magnet molded into a plastic slide to actuate a reed switch,
mounted on a p.c. board sealed inside the toothbrush. MEDER says
its SMD Reed Sensors, such as models MK15, MK16, MK17, are preferred
for this type of sealed application.
Appliance OEMs are saving costs
by doing less of the design work themselves. Mertik
Maxitrol (Southfield, MI, U.S.) Managing Director Larry C. Koskela
says, “OEMs are generally shifting design and engineering responsibilities
(opportunities) to suppliers, as they streamline staff to reduce their
costs. This creates opportunities and is an investment for suppliers
that requires a return.”
When the controls and sensors
supplier becomes responsible for providing a controls solution, rather
than providing a specific component, a window of opportunity opens for
using new configurations that increase capabilities and save costs, which
can sometimes even be calculated across several appliance models. More
appliance companies put increased significance on the ability to leverage
design commonalty to achieve reduced control and sensor part numbers
in their inventory.
“We at MEDER see it as
a growing priority; however, only if it does not compromise functionality,” says
John Beigel, MEDER president and CEO. “Obviously for the end user,
the greater commonalty he can achieve, the better he is able to take
advantage of supplier manufacturing efficiencies to reduce cost.”
Peter Buesch of Intercontrol (Nuremberg,
Germany) says he sees some customers interested in using combined systems
in order to reduce their overall costs, but believes this strategy is
mostly for the largest, most international player in the appliance industry.
D6A filter sensor contains a microprocessor with complex algorithms
that provide a temperature reference point used to determine if
a filter fan is moving the correct amount of air. Omron
Electronics LLC of Schaumburg, IL, U.S. said it is the first
sensor of its kind. If the sensor indicates that the airflow is
at unacceptable levels, it can alert the user that the filter is
clogged. This capability allows the sensor to help protect expensive
equipment from breakdowns resulting from clogged filters. The temperature
range of the filter sensor is 0°C to 45°C and its supply
voltage is d.c. 12 V +/-10 percent. Its current consumption maximum
is 60 mA and output voltage is 0-5 V. Potential applications include
machines using a filter fan, such as cash registers, servers, and
uninterruptible power supplies.
The inherent versatility of
electronic controls, stemming from their programmability, makes them
conducive to design commonalty.
“Fenwal employs a microprocessor-based
platform that allows rapid control customization by changing software
algorithms rather than by developing new circuits,” points out
To make controls specification
even easier and faster, Fenwal maintains
an inventory of fully assembled controls that can be coded on command
to match a customer’s application needs. “With the elimination
of hardware manufacturing lead times, an application-specific control
can be brought to market very quickly,” Mr. Swanson says. “By
offering a wide range of timing and wiring options, we are able to respond
to the level of customization demanded by appliance makers.”
Mr. Koskela sees a great deal
of interest by OEMs in limiting not just the number of parts they use,
but the number of suppliers as well. “Hence, the use of common
components platforms is very desirable,” he explains. “It
is a strong consideration for our own product development activities
as we try to secure business with our OEM customers.”
of Cary, NC, U.S., supplies sensors based on a continuous level
sensing technology called SEF (Shaped Electromagnetic Field).
The sensors offer an alternative to resistive float and arm devices.
SEF-based sensors offer floatless operation and absolute measurement
while taking up less space, and they are said to do so at a cost
parity in volume. SEF technology sensors can be shaped to linearize
the volume output in tanks with non-uniform, irregular cross
sectional areas as the level rises.
can also be shaped to fit into serpentine paths. Current sensor
models are flat, roughly in the shape of a small ruler, but
round models are also feasible. Non-invasive external mounting
is also possible for use in plastic tanks. This level sensing
technology has applications potential in medical systems, monitoring
medications, and therapy fluids. It can measure water levels
in appliances and food and drink systems.
The ever-expanding capabilities
of electronics at lower price points makes them more attractive for achieving
space savings, more precise measurements, additional features, and sometimes
for quality and reliability advantages.
“Mechatronics can be
defined as using electronics to accomplish tasks that traditionally have
been done by mechanical solutions or by integrating the electronics into
the mechanical component,” says Mr. Caldwell of Microchip
Technology. “The objective of mechatronics is to achieve an
advantage for the consumer or appliance OEM at the same or lower costs.”
For example, eliminating wires
and other cost savings can be realized by putting electronics inside
a switch instead of having a separate board, Mr. Caldwell explains, adding, “Secondary
benefits include better reliability and a smaller footprint.”
Maxitrol’s new e-flame is a radio frequency-operated,
battery-powered remote ignition and control system. The e-flame
Remote Electronic Ignition System, Model GV60, consists of a
combination control, a receiver, and a remote handset.
Still, the demise of the electromechanical controls has never been less likely—for
so many applications they remain the best possible solution.
“We notice that the trend is: electronic controls if applicable
and required and electromechanical controls in cases of cost reduction,” observes
Mr. Buesch of Intercontrol.
He adds, however, that there is much room for innovation in electromechanical
controls by creating systems with a higher degree of component integration
and expanded functionality.
Innovative designs are also making controls more configurable, further
extending their range of usability.
“They will continue to be widely used for applications that need
to sense a high temperature limit or require agency approvals,” Mr.
Swanson of Kidde-Fenwal says. “Although
some electronic controls are now entering the market at attractive price
points—compared to their mechanical counterparts—there are
applications where mechanical controls are the most cost-effective.”
Miniaturization techniques are helping to make them attractive in some
“Reed sensors are becoming smaller and smaller with longer and longer service
life. MEMS devices are being used when extremely small space is required,” says
Mr. Beigel of MEDER. “All
these factors create different opportunities, especially in the appliance industry.”
Electronics and electromechanical controls and sensors are increasingly
being called on to work together. Many OEMs are requiring an interface
capability between mechanical valves and electronics from their suppliers.
“The advent of building management systems and energy management
systems is making a large impact on the necessity of electronics and mechanical
valve interfaces,” says Mr. Koskela of Mertik
35 Series control integrates two functions: hot surface ignition
with precise temperature control. It can be configured for applications
such as water heaters, commercial boilers, pool and spa heaters,
and cooking appliances.
When integrated control systems
come into play, the electronic vs. electromechanical decision becomes
a non-issue. An integrated system is designed using whatever components
are best for achieving the overall solution. Hybrid controls sometimes
offer the best of both worlds.
Karl Renau, president of Renau
Electronic Laboratories in Chatsworth, CA, U.S., sees great potential
in hybrids. The company makes hybrid digital controllers used extensively
in institutional appliances such as washing machines, boilers, fryers,
“In April of 2003 we
brought our new hybrid digital thermostat to the market,” Mr. Renau
says. “It is a control designed to replace the mechanical thermostat
in a number of applications such as we currently serve.”
Calling its controls hybrids means
Renau married elements of electromechanical controls and solid state
components, forming a single control. “The advantage we get with
this hybrid design is extreme durability,” Mr. Renau explains. “We
estimate this design extends the life of the control 10 times compared
to a mechanical control.”
This high level of durability
is achieved even in the controls’ harsh operating environments,
fascinated by fully encapsulating it. Other significant advantages are
cost savings and reduced size, Mr. Renau says.
One of Renau’s appliance
industry customers has used a high-durability Renau control for some
time. The control unit was made up of several components combined and
Conforma-coated for extra resistance to harsh environments.
Today, the appliance producer
uses Renau’s hybrid control, which has been compressed into about
one-third the size of the previous unit. The new component, which controls
the entire appliance, costs about half as much as the previous unit.
Another advantage of the Renau hybrid is its flexibility. Like an electronic
control, it can be programmed to accommodate new applications, so an OEM can
use a single component for a variety of appliance designs.
“Hybrids are not used
that much, yet,” says Mr. Renau. “With these cost and durability
advantages, I think hybrids represent the future of controls in many
The future means increasingly
sophisticated electronics, an array of new controls and sensors technologies,
and the reinvigoration of traditional electromechanical components through
innovative reconfiguration and integration. To the appliance producer,
this might translate into a more complicated specification process.
On the other hand, OEMs who find themselves partnered with the right supplier
may find themselves with less costly, more capable controls solutions.
Systems, Inc. of Boxborough, MA, U.S., added a 24 V a.c. excitation
to its Model 265 Series of differential pressure transducers and
transmitters for HVAC system manufacturers, designed to reduce installation
costs while increasing overall operating efficiency. The transducers
offer +/-1 percent full scale accuracy, with optional accuracy of
+/-0.5 percent, +/- 0.4 percent, +/-0.25 percent. The Model 265 is
designed for superior positive and negative pressure sensing, as
is required for high-efficiency air control systems. The unit detects
pressure ranges as low as 0.25 in up to 100-in of water column full
scale, with 10 PSI overpressure on all ranges. It can also be configured
with a choice of voltage output (0-5 V d.c. or 0-10 V d.c.) or current
output (4-20 mA), and 12 or 24 V d.c. (nominal) excitation.
witnessed an acceleration of microprocessor technology being incorporated
into today’s newest appliances. "Perhaps as much as 50 percent
of the applications Fenwal is looking at are ones that have become possible
only because of technology that has been developed within the past 2
years," says Gordon Swanson, controls engineering manager, Kidde-Fenwal.
"Fenwal recently introduced
a digital temperature controller platform which has been designed for
flexible manufacturing," he says. "Configuration is quicker
and simpler than with other digital controls and can be accomplished
during the manufacturing process."
Fenwal is also looking at the
continuing innovations occurring in the communications capability of
temperature controls. In many industries, such as cooking, refrigeration,
and pharmaceutical, data integrity is a concern. Mr. Swanson says that
many controls coming from disparate manufacturers will soon be able to
communicate with each other, making data more manageable.