STEMMA QT cables are used to connect the VL53L4CD time of flight sensors. The cables need to be cut so that the SCL and SDA wires can be soldered to the TCA9548A breakout board, while keeping the power and ground wires connected to the QT connectors.

Prep the STEMMA QT Cables

Cut the SCL and SDA (blue and yellow) wires close to one end of the QT connector. Slide those wires through the heatshrink tubing on the cable. Splice and tin the SCL and SDA wires.

Repeat this process for a total of seven cables.

For the eighth cable, cut the SCL and SDA (blue and yellow) wires close to one end of the QT connector. Then, at the opposite QT connector, cut the power and ground (red and black) wires.

You should have one cable that's power and ground only connected to a QT connector and another cable that's SCL and SDA only connected to a QT connector. Splice and tin the wires.

Plug in the STEMMA QT Cables

Plug the the STEMMA QT cable into the first VL53L4CD board on the left. The connector with all four wires still connected should be plugged into the board's right-hand port. Plug the other end of the cable, with only power and ground connections, into the left-hand port of the next VL53L4CD.

Continue plugging in the remaining six cut cables in this pattern: connector with all four wires plugged into the right-hand port, connector with power and ground only into the left-hand port.

Plug the SCL and SDA only STEMMA QT cable into the open right-hand port in the last VL53L4CD board on the right.

Plug the power and ground only STEMMA QT cable into the open left-hand port in the first VL53L4CD board on the left.

Extend the SCL and SDA Wires

Cut, splice and tin 16 pieces of wire. These wires will be used to extend the SCL and SDA wires from the STEMMA QT cables. As a result, you can color coordinate them by cutting eight blue wires and eight yellow wires.

The wires should be the following approximate lengths:

  • Four pieces (two blue, two yellow) measuring 32 mm
  • Four pieces (two blue, two yellow) measuring 177.8 mm
  • Four pieces (two blue, two yellow) measuring 285.75 mm
  • Four pieces (two blue, two yellow) measuring 304.8 mm

Cut, splice and tin all of the wires' ends.

Solder the cut wires to the STEMMA QT wires.

  • The 304.8 mm wires are sized for the first and last VL53L4CD's.
  • The 285.75 mm wires are sized for the second and seventh VL53L4CD's.
  • The 177.8 mm wires are sized for the third and sixth VL53L4CD's.
  • The 32 mm wires are sized for the fourth and fifth (two in the middle) VL53L4CD's.

Add heat shrink to all of the soldered wire connections.

This guide was first published on May 10, 2022. It was last updated on 2022-05-10 22:10:08 -0400.

This page (STEMMA Wiring) was last updated on May 10, 2022.

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