A Fortune 200 company needed a turnkey, DC voltage, agency-compliant electronic control solution capable of providing motion control with memory position capabilities and auto run/sense features for a multi-motor application involving four motors. Particularly important to the design criteria was the development of an interactive system of wireless remote control capabilities and other user interface devices, including iPhone and iPad interconnect devices. It was a complicated job, and the company would need to partner with experts who could deliver a time- and cost-effective solution.

Challenges

This project required creation of high-reliability designs operating in an environment of multi-media devices while avoiding RF interference issues and providing for the highest reliability for home and commercial applications.

The project quickly grew to more than just a motor control design project. The company chose Buse Industries (Bridgeton, MO) to assist in the development of the look and feel of new remotes so they were cost-effective to manufacture. Buse helped determine the type of backlighting, how text was applied, the look and feel of buttons, and overall appearance of the remotes.

As this controls package was geared for the consumer market, cost and features had to balance. There were many rounds of concept designs needed in order to determine the best cost structure for the type of electronics used. The final product would need to meet a globally competitive cost base.

Applications would need to be developed to run on both iOS and Android devices. The general communication method chosen was Zigbee to allow for the possibility of operating multiple systems in close proximity. Using this communication method eased the burden on communication programming and agency submittals. Buse also used this to reduce the possibility of interference in the consumers’ home from other communication items such as Wi-Fi, Bluetooth, and cellphones. For the secondary communication, Buse used Bluetooth modules to provide connectivity for Android and iOS systems.

Electronics needed to last ten years, making component selection critical. For months, there were cycle tests running to simulate five years of operating time. Balancing performance and cost without effecting overall quality was crucial.

Solution

There are many elements to consider when deciding what type of motor is optimal for creating the motion to be controlled and the type of feedback used for position sensing.

Historically, AC induction motors have been a workhorse for this industry, providing high-torque, relatively quiet operation and long life. However, AC motors tend to be difficult and more expensive to incorporate speed control.

In contrast, permanent magnet DC motors offer a quiet, low-cost solution. Additionally, brush, commutator, and magnet technology have allowed DC motors to meet life specifications. Advances in electronic filtering systems on DC motors have eliminated electrostatic discharge (ESD) and other electrical noise issues that have plagued both home appliances and control software designers. More efficient designs are available to reduce current draw (and ultimately lower-cost power supplies), and DC motors offer simpler and lower-cost speed control options, giving the designer the options of slow start, stops, and position controls.

The different feedback options considered are timer-based systems, potentiometers, Hall effect sensors, and reed switches. Timers are not generally the best option with DC motors, as the full load speed of the motor can vary depending on load. Potentiometer feedback can be expensive and provide challenges to mechanically incorporate. Hall effect sensing (with magnets) may be most accurate, but generally is more expensive than reed switch (with magnet) designs. The end goal is a reliable system with quiet operation and maximum life at the best value-cost position.

Based on the needs of the customer, Buse began work on control PCB development, PCB layout, schematics, embedded logic software development, integration, validation, and design and development of the base control system and enclosure designs for the project. Additionally, all accessory enclosure designs would need to be designed and developed, including the development of multiple plastic injection molds and the submittal of these systems for FCC testing and approval, along with agency compliance design, testing, and approval.

Buse championed the overall program plan, and managed timelines and critical milestone achievement dates for program launch, including UL agency listing and approval of the product. The Buse solution included battery backup features along with multi-interface designs and supplemental control design variations in order to meet good, better, and best product line offerings. Additionally, Buse provided for multi-customer application rendition varieties of the system package, offering niche market and alternative branding opportunities.

This article was contributed by Buse Industries. For more information, Click Here .