Using the V5 3-Wire Expander

The V5 3-Wire Expander is a device which can be plugged into a V5 Brain’s Smart Port and creates eight additional locations to plug in 3-Wire devices.

3 wire expander

What is the V5 3-Wire Expander

Smart Port

The 3-Wire Expander is a device used to add additional 3-Wire ports to the V5 Brain. The V5 3-Wire Expander has a V5 Smart Port on one end to connect to the V5 Brain and eight 3-Wire ports on the other.

8 ports

The other side of the 3-Wire Expander has eight 3-Wire ports.

Why use a 3-Wire Expander?

When beginning a project, it might seem impossible to use all eight 3-Wire Ports on the V5 Brain. However, as projects and robots become more advanced, the 3-Wire Ports quickly start to fill up.

Each device listed here requires the use of at least one 3-Wire Port.

8 ports

The 3-Wire Ports on the V5 Brain can become quickly filled. The 3-Wire Expander can add eight additional ports and double the amount of 3-Wire Ports that can be used for advanced robotic behavior.

How to Use a 3-Wire Expander

V5 Wire Exapander and Brain

The 3-Wire Expander can be plugged into any one of the 21 Smart Ports on the V5 Brain by connecting a V5 Smart Cable between the V5 Brain and the Smart Port on the expander.

Smart Cable Plugged in

Be sure the Smart Cable is fully inserted and locked into the ports of both the V5 Brain and the 3-Wire Expander.

V5 Wire Expander

Any 3-Wire device or a 3-Wire extension cable for a device can be plugged into any of the eight 3-Wire Ports on the 3-Wire Expander. Be sure the 3-Wire cable is fully inserted into the 3-Wire Port. The port and the 3-Wire cable both have a key which should only allow the cable to be plugged in with one orientation.

 3 wire expander

The 3-Wire Ports on the 3-Wire Expander are designated sequential as ports A through H from left to right.

VEXcode V5 Icon

The 3-Wire Expander needs to be paired with VEXcode V5 or VEXcode Pro V5 to create a user project for the V5 Brain.

How to Mount a 3-Wire Expander

V5 Wire Expanders

The device can be easily mounted to any piece of the VEX structural metal.

The 3-Wire Expander has a mounting hole. This mounting hole passes through the device in which a screw can be placed. This screw can then be inserted into the hole of a piece of structural metal to be attached with a nut. On the bottom of the 3-Wire Expander is a round boss which will fit into a hole of the structural metal and provide a second point of contact for the device.

How to configure devices with the 3-Wire Expander

VEXcode V5 Icon

Launch VEXcode V5

Device icon

Select the Devices icon.

Add a Device

Select ‘Add a device.’

Select 3 Wire Expander


Select Smart Port

Select the Smart Port that the 3-Wire Expander is plugged into on the V5 Brain. Once the port is chosen, select ‘DONE.’

Note: the name of the 3-Wire Expander can be changed in the text window from Expander1 to a different name. For more information on how to change the name of devices, view the 3-Wire Devices article from the VEX Library.

Add a device

To add a 3-Wire device to the Expander, select ‘Add a device’.

Note: in this example, assume there is a Bumper Switch plugged into 3-Wire Port “A” on the V5 3-Wire Expander.


Select ‘3-WIRE.’

select bumper

Select ‘BUMPER.’

choose expander

Under ‘Select 3-Wire Source,’ select ‘Expander1.’ The port also needs to be selected. Select port ‘A,’ then ‘DONE’ to finish the Device Setup.

For more on 3-wire Port Architecture

For more information, help, and tips, check out the many resources at VEX Professional Development Plus

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