Sensor Fusion Box Details

This page provides information on how to purchase or assemble a Sensor Fusion Box. The Sensor Fusion Box is used in the CameraITS sensor_fusion test and multi-camera sync test. It provides a consistent test environment for measuring timestamp accuracy of camera and other sensors for Android phones. It consists of plastic box components that are laser cut from computer-aided design (CAD) drawings and a Servo Control Box.

You can purchase a Sensor Fusion Box or build your own.

Purchasing a Sensor Fusion Box

We recommend purchasing a Sensor Fusion Box from one of the following qualified vendors.

  • Acu Spec, Inc.
    990 Richard Ave, Ste 103, Santa Clara, CA 95050
    fred@acuspecinc.com
  • MYWAY DESIGN
    4F., No. 163, Fu Ying Rd., New Taipei City, Taiwan
    sales@myway.tw
    http://www.myway.tw/

Building a Sensor Fusion Box

This section includes step-by-step instructions for assembling a Sensor Fusion Box from laser-cut acrylonitrile butadiene styrene (ABS) components (shown in Figure 1):

CAD drawing of Sensor Fusion Box components
Figure 1. Mechanical drawing of Sensor Fusion Box components

Required tools

Before starting, ensure you have downloaded the technical drawings for the Sensor Fusion Box (included in the Sensor Fusion Box zip file) and have the following tools available:

  • Phillips head screwdriver
  • Hex keys
  • Power drill set
  • Exacto knife
  • Tape

Step 1: Apply vinyl stickers

After creating the ABS components with a laser cutter, apply vinyl stickers to the plastic box to get the proper color control on the interior of the test box:

  1. Apply vinyl on the smooth side of the ABS as shown in Figure 2. For helpful tips on applying vinyl, refer to wikiHow.
  2. Cut out the necessary holes on the vinyl with the exacto knife.

    BS pieces
    Figure 2. ABS pieces with vinyl applied on the smooth side (interior of the box)

Step 2: Prepare phone mount and attach servo mount

To prepare the phone mount to attach to the servo:

  1. Tap 16 holes on the phone fixture with ¼" - 20 and make countersink holes on the back of the phone fixture.

    Phone fixture holes
    Figure 3. Phone fixture with tap and countersink holes

  2. With the large shaft that came with the servo, drill pilot holes with a #43 drill bit (2.26 mm) into the last holes from each side so 4-40 screws can be inserted through the holes.

    Servo shaft
    Figure 4. Servo shaft with pilot holes at each end

  3. Insert and tighten the flat-head 4-40 screws as shown in figure 5 on the front of the phone fixture and tighten the shaft as shown in figure 6.

    Shaft and screws
    Figure 5. Flat-head 4-40 screws

    Shaft
    Figure 6. Shaft on the back of fixture, tightened by screws applied from the front

Step 3: Attach phone clamps

To attach the phone clamps:

  1. Apply nylon thumb screws, rubber adhesive, and wire spring to the aluminum clamp.

    Clamp with rubber adhesive
    Figure 7. Clamp with rubber adhesive, thumb screws and wire spring

  2. Screw the phone clamps' thumb screws into the tapped holes of the phone fixture as shown in figure 8. You can adjust the location of the phone mounts depending on the size of the phones as shown in figure 9.

    • Mechanical drawing:

      CAD drawing of clamp attachment
      Figure 8. Mechanical drawing of clamp attachment to phone fixture

    • Phone mounts attachment to phone fixture:

      Assembled phone fixture
      Figure 9. Assembled phone fixture

Step 4: Assemble sliding door rail

  1. Fix sliding panel rails on the top and bottom of the box towards the front. Figure 10 shows 6-32 screws on pre-tapped holes. Alternatively, you can use self-tapping screws.

    Fixed rail
    Figure 10. Fixed sliding panel rail on top and bottom of box

Step 5: Attach lighting

To attach the light brackets and diffuser:

  1. Stack two handle pieces on top of each other and assemble them using 6-32 screws (or use self-tapping screws).

    Handle pieces and assembly
    Figure 11. Sensor fusion box handle pieces and assembly

  2. Prepare four 4-40 screws, nuts, and acorn nuts to fix the mounting bracket from the lighting kit to the wall of the box.

    Screws and bracket on interior wall
    Figure 12. 4-40 screws and light bracket on the interior wall of the box
    Exterior with bolts applied
    Figure 13. Bolts and acorn bolts applied to the screws from the exterior of the box

  3. Cut the light diffuser to an appropriate size to wrap the light strips.

    Light strips and diffusers
    Figure 14. Light strips and light diffusers

  4. Wrap the light diffuser around the strip and tape it at the back.

    Strips and diffusers taped from back
    Figure 15. Light strips and light diffusers taped from the back

  5. Snap the lights into the brackets (can be a tight fit).

    Lights on interior wall
    Figure 16. Lights not mounted in brackets (left). Lights mounted in brackets (right).

Step 6: Attach phone fixture to servo plate

To attach the phone fixture to the servo plate:

  1. Prepare four 6-32 screws and a servo plate to fix the servo onto the wall. Fix the servo onto the interior wall and insert the screws from the inside into the servo plate on the exterior wall.

    Servo and servo plate
    Figure 17. Servo and servo plate held in place with 6-32 screws

  2. Secure phone fixture onto the servo with nylocks (pushing the center of the shaft into the servo's rotation center).

    Phone fixture on servo
    Figure 18. Phone mount fixed on servo shaft with nylocks

  3. Screw the phone fixture onto the servo with its servo screw.

    Phone fixture on servo with screw
    Figure 19. Securing phone fixture onto servo with servo screw

Step 7: Final assembly

To complete assembly of the Sensor Fusion Box:

  1. Secure servo control box on the left of the servo with 4-40 screws from the outside and fasten from the inside with nuts.

    Servo control box on wall
    Figure 20. Secure servo control box onto the wall

  2. Tape the box together, then screw the parts together (you might need to pre-drill holes in some parts).

    • Assembled Sensor Fusion Box:

      Taped box
      Figure 21. Taped box with motor assembly and servo control box and screw detail

  3. Print out a colored copy of the checkerboard (included in the Sensor Fusion Box zip file) on A3 (or 11 x 17 inch) paper, and tape it on the opposite wall of the phone fixture.

    Make sure the red dot in the center of the checkerboard is directly facing the camera when placed on the fixture, as shown below.

    Checkerboard
    Figure 22. Checkerboard printed and taped to the opposite wall of phone fixture