Development of a Modern Dental Chair Control Board with IoT Capabilities

DENTALEZ, the dental equipment manufacturer with over a century of tradition, offers a wide array of dentistry products and devices including dental chairs, compressors, tools, and vacuums. These are known for their technological advancement, simplicity, and reliability.

One of the flagship products of DENTALEZ is a high-end dental chair, the 6400 Dental Patient Chair. The product features a hydraulic cantilever mechanism and mechanical assistant instrumentation. It offers a wide run of motion and is controlled by a dedicated PCB.

The project's background:

This PCB, called the Control Board, was reaching its inevitable obsolescence. Because of that DENTALEZ started looking for a new design partner such as Conclusive. The customer needed a new Control Board for the chair to replace the existing design and resolve the issue of its component obsolescence.

The new version had to support the existing chair interface and mounting points to reduce the impact on the whole project and even allow old broken Control Boards to be replaced with new ones, thus eliminating any need to keep a stock of old boards around. The other goal was to update the design with a new cloud connectivity interface for easy updates, statistics gathering, and maintenance.

This interface would later be populated with a specialized add-on board that would enable these features and provides necessary wireless cellular interfaces. The new design had to be crafted with longevity in mind, such that manufacturing continuity could be maintained over at least a 10-year lifespan.

The DENTALEZ also set unit price constraints that should have not been exceeded.

The summary of the project’s top priority goals:

  1. Solve component obsolescence issues.
  2. Modernize and enhance the chair's capabilities by enabling an interface for internet-based telemetry data transmission.
  3. Prepare the documentation for the product to comply with IEC Compliance: Medical Electrical Safety per IEC 60601-1 3.1, Medical EMC Test per IEC 60601-1-2 (2014-2), Medical Device Software per IEC 62304.

Solution:

As mentioned above, the solution has been split into two distinct hardware components:

  1. Control Board: the board used to control the chair’s movement and handle the operator’s commands
  2. IoT Board: a daughter board for the Control Board, enabling the transmission of telemetric data to cloud databases through cellular network

Additionally, the IoT board design could be greatly sped up, by utilizing an additional off-the-shelf solution from Particle. Particle is a provider of hardware and software solutions for enabling IoT devices with cloud connectivity. Conclusive is Particle’s design partner, so a suitable solution could be easily selected from Particle’s design portfolio.

The IoT board has been equipped with B-SoM from Particle greatly simplifying the rest of the hardware design of the IoT board. The benefits of using Particle’s solution extended to the software area as well, as Particle’s SDK contained all the necessary primitives and boilerplate designs to speed up the development of a new application.

Thanks to the modular design the Control Board could be finalized prior to the IoT board. Given that, the implementation of the new features did not affect the timeline for handling the obsolescence of the old Control Board.

In addition to designing the hardware layout and software, we meticulously planned the entire solution to seamlessly integrate with the Client's device, addressing aspects such as mounting points, connectors, cable lengths, and more. Furthermore, we handled the manufacturing and assembly of the final device and conducted the release tests in-house.

We also managed the prototypes and production runs, eliminating the need for the Client to depend on additional external companies or subcontractors. They received a fully finished product, ready for integration into their manufacturing pipeline, without incurring additional overhead costs or requiring significant changes to their current manufacturing tooling and procedures.

The hardware was designed using Altium Designer. Prototyping occurred locally, followed by rigorous testing and preparation for full-capacity manufacturing. We initiated a custom production run of the final PCB boards utilizing local facilities.

The software was developed using the C programming language and a bare-metal approach for the chair controller, while the cloud-enabling solution was implemented in C++ using Particle’s SDK.

We also provided integration with the Client's existing cloud service and collaborated with the Client's team working on the integration of the new Control Board + IoT Board solution into the cloud application. Integration and testing of both pieces of this solution was a collaborative effort between the parties.

Scope of work:

The tasks of the Conclusive Engineering’s specialists were as follows:

  1. Hardware
    1. Redesign of the old dental chair control board: Incorporate a modern microcontroller, an efficient and flexible (120-240 VAC) power solution, additional connectors, and debug features (OLED display, functional LEDs).
    2. Design the IoT board: An additional board for the control board, equipped with sensor interfaces and an efficient power solution.
  2. Firmware and software
    1. Prepare a completely new firmware for the control board: which includes numerous new features and a new bootloader.
    2. Design a PC test software for the control board.
    3. Develop firmware for the IoT board: Facilitates communication with the cloud, including telemetry, device statistics, and warnings.
  3. Documentation
    1. IEC Compliance: Medical Electrical Safety per IEC 60601-1 3.1
    2. Medical EMC Test per IEC 60601-1-2 (2014-2)
    3. Medical Device Software per IEC 62304
  4. Manufacturing
    1. Prepare production documentation.
    2. Set up a test rig for quick testing of newly manufactured control boards.
    3. Manage the production of prototypes and production series.

The project's key results:

The final product is a competitive dental chair equipped with individual patient presets and cloud-enabled communication capabilities for data gathering, remote update deployment, predictive servicing, and other features that enhance usability, and user experience, and enable agile development based on data analysis results with an at least 10-year longevity.

The key deliverables received by the customer:

  1. Production-ready devices: Control Board and IoT Board,
  2. Hardware source files and production files,
  3. Firmware source files,
  4. PC test software,
  5. Software documentation,
  6. Certification documentation.

Technologies used:

  1. Hardware: Altium Designer
  2. Microcontroller:
    1. Control Board: Features a Cortex-M4 SAM4L microcontroller, equipped with our custom firmware.
    2. IoT Board: IoT Board: Based on Particle B-SoM and equipped with our custom application to communicate with the control board and DentalEZ cloud services.
  3. Programming languages: C, C++, Delphi (PC test application)

Team:

  1. HARDWARE: Mateusz Gancarczyk, Wojciech Kloska
  2. FIRMWARE & SOFTWARE: Mateusz Gancarczyk
  3. DOCUMENTATION: Michał Podziomek, Mateusz Gancarczyk
  4. PRODUCTION: Patryk Kozina, Mateusz Gancarczyk