Step 7:

Build the piece shown below.

This image may be used for scaling purposes if the length of the black bar used in step 7 was unclear.

Step 8:

Gather the two pieces created in steps 4 - 6 as well as step 3. Attach them as depicted.

Step 9:

Now, attach the pieces created in step 8 to the piece created in steps 1 - 2.

Step 10:

Create the pieces depicted below. Note that the black connector piece in the grey piece in the center is a double-length black connector piece.

Step 11:

Assemble the pieces as shown. The black connector piece connects to the last hole in the sensor.

Step 12:

Create a mirror image of the piece in step 11, sans the grey bar.

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