TIDUC26A April   2022  – April 2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Inductive Touch Buttons
      2. 2.2.2 Sensor Coil Placement
      3. 2.2.3 Collecting Data from Multiple LDCs
      4. 2.2.4 Magnetic Dial Implementation
      5. 2.2.5 CORDIC Algorithm
    3. 2.3 Highlighted Products
      1. 2.3.1 LDC3114-Q1
      2. 2.3.2 TMAG5273
      3. 2.3.3 DRV2605
      4. 2.3.4 TLV75518
      5. 2.3.5 TCA9534
      6. 2.3.6 PCA9543
      7. 2.3.7 Sensor Control Board
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Firmware and Programming
      1. 3.1.1 Operational Mode 1
      2. 3.1.2 Operational Mode 2
      3. 3.1.3 Operational Mode 3
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 ABS Force Response
      2. 3.3.2 ABS Gain Corrected
      3. 3.3.3 Nylon Force Response
      4. 3.3.4 Nylon Gain Corrected
  10. 4Hardware Components
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6Revision History

4 Hardware Components

The 3D printed housing is separated into different components and assembled into the final housing. These components were designed for a Selective Laser Sintering process that uses Nylon 12 as the material. This gives the button surface slight flexibility to bend and allows for the magnetic dial to rotate smoothly. The design starts with a housing base that provides a rigid surface for the PCB to sit in as well as a hole for the USB cable and multiple holes for the bolts to secure the housing shut.

GUID-20220302-SS0I-GSH3-R7VP-QJQQL9B7LDNF-low.png Figure 4-1 Housing Base

The PCB rests inside the groove around the outside of the base along with the SCB attached.

GUID-20220302-SS0I-RGSN-TPCT-3W94S9GQWTGT-low.png Figure 4-2 Housing Base with PCB

The top cover is broken into multiple parts to make it easier to print with some 3D printing technologies. These different parts are the button surface, a dial attachment, the dial, and a small cover for the top portion of the PCB. The button surface has grooves on the top to show where a button press needs to occur and a hole in the middle for the dial attachment piece to sit in. On the back, there are rectangular cutouts for the metal targets to be added into. To obtain the best mechanical isolation, the button cover is adhered to the PCB as well as bolted to the housing base. This portion of the design was built to match the button stackup design previously mentioned.

GUID-20220302-SS0I-DMVB-PDC0-P65SGQKXL3LC-low.png GUID-20220302-SS0I-V53F-6ZJL-F06SCFNSC9NS-low.png

Figure 4-3 Housing Button Cover

The dial attachment is a small round piece that sits in the hole of the button surface. The main purpose is to provide a spot for the dial to clip into. The dial attachment needs to be fixed to the button surface with glue to make sure that it does not move when using the button.

GUID-20220302-SS0I-W0ZP-NBLP-BCV3JB2BQK6B-low.png Figure 4-4 Button Cover with Dial Attachment

The dial is designed to clip onto the dial attachment with a spring sitting between the two. The dial also has a small hole that the magnet gets glued into. This allows for the magnet to sit directly above the TMAG5273 for best rotational sensing measurements.

GUID-20220302-SS0I-GSMB-SHFB-QFDW2VWXFVCZ-low.png GUID-20220302-SS0I-JMR2-0KMN-VKCNWXH05BPT-low.png

Figure 4-5 Magnetic Dial

The small top cover has some cutouts to let the LEDs be visible even when the cover is on as well as a cutout for the USB cable to connect to the SCB. The main purpose of the top cover is to complete the housing and hold the SCB in place.

GUID-20220302-SS0I-HRP0-SPGV-XC3GKTZDFSXF-low.png Figure 4-6 Full Assembly