Install the QTI Line Sensors


  • (1) SumoBot, built up at least through the end of the Add Cables for Front QTI Sensors page
  • (2) QTI line sensors
  • (2) #4-40 1/2" long pan-head machine screws
  • (2) 1/8" Nylon spacer
  • (2) 1/16" Nylon spacer


  • Position the parts on each screw in this order:
  • QTI with parts facing the same direction as the screw’s head
  • 1/16” nylon washer
  • 1/8" nylon washer.


  • Connect each screw (with its QTI and washers) to a front standoff (by the plow).
  • Make sure the pins of each QTI point inward -toward the slot where you just inserted the cables.


  • Connect the cables you fed through the chassis to each QTI.
  • Make sure that each cable’s:
    • White wire is connected to the QTI’s W pin
    • Red wire is connected to the QTI’s R pin
    • Black wire is connected to the QTI’s B pin
  • Set the SumoBot face down on the table with its underside facing toward you, and identify the left and right QTIs.  
  • Follow the cable from the left QTI to its other end, and mark it L with masking tape.
  • Repeat for the right cable.


  • Connect the QTI marked L to the P13 header and the QTI marked R to the P14 header.  
  • Make sure each cable’s:
    • Black wire is connect to the pin labeled GND
    • Red wire is connected to the pin with a label that begins with P (like P13 and P14).
    • White wire is connected to the pin labeled 5V.


  • Remove the L and R labels from the QTI cables.
  • Put the batteries back into the battery holder.
  • Connect the battery power plug to the barrel jack.