4. Wiring and Final Assembly
We now proceed to the critical wiring stage of Cone-e. This section covers the primary power and communication connections required for system operation.
The block diagram below provides a high-level overview of Cone-e’s wiring architecture, illustrating how power is distributed and how the major subsystems are connected.
First, connect the motor drive input power wires. Connect the positive leads to the fused power rail and the negative leads to the common ground rail.
Ensure that all eight motor drive inputs are properly connected before proceeding.
Next, connect the output wires (yellow and black) from the 12V, 30A DC-DC converter to the positive and negative terminals of the fuse box, respectively.
Verify correct polarity before securing the connections.
Connect the emergency stop switch to the base using the normally closed contact.
Splice the positive rail from the Anderson connector and route it through the normally closed terminals of the emergency stop switch. From the switch, connect the positive output to the terminal block.
Connect the negative rail from the Anderson connector directly to the terminal block.
Connect the positive input terminals of all four buck converters together on the positive rail, and connect the negative input terminals together on the negative rail.
Before making these connections, ensure that there is no electrical connection between the positive and negative rails.
Note: Verify using a multimeter that there is no continuity between the positive and negative sides before proceeding. This step is critical.
Connect the output of the 24V, 6A DC-DC converter to the input terminals of the lift motor controller (BTS7960), connecting positive to Battery+ and negative to Battery−.
Add lift wiring photo
Connect the lift motor wiring to the motor driver and the Raspberry Pi Pico using male-to-female and female-to-female jumper cables, as shown in the reference image.
Connect the lift encoder and motor driver wiring as follows:
Encoder connections: (Lift to Pico)
Encoder A → GPIO 27
Encoder B → GPIO 28
Encoder V+ → 3.3 V
Encoder GND → GND
Place a 1 µF capacitor across Encoder V+ and Encoder GND
BTS7960 motor driver logic connections: (Lift Motor Driver to Pico)
RPWM → GPIO 2
LPWM → GPIO 3
R_EN → GPIO 4
L_EN → GPIO 5
VCC → 3.3 V
GND → GND
Add complete lift photo wiring photo
Extend the output wires from the 24V, 6A DC-DC converter using two inline Wago connectors. Ensure the extended wires are at least 1.2 meters long to allow routing to the arm power system.
Attach two 3-port Wago connectors at the opposite end of the extended wires.
Add wire extension photo wiring photo
Also, add two sets of positive and negative wires from the fuse box, each at least 1.2 meters long, to supply power to the Orin and the U2D2. Terminate these wires with barrel jacks, one for the Orin and one for the U2D2 power board.
Ensure that none of the output wires from the buck converters are left exposed or hanging loose, except for the 5V, 5A Type-C output used to power the Raspberry Pi.
Put eight 10 Amps fuse in for all the swerve motor drivers and two 5 amps fuse in for the Orin and the U2D2.
We will now proceed to a critical step: updating the firmware on the swerve drives and assigning the appropriate CAN IDs. Update the firmware on all swerve motors to version 25.X.X, then assign a unique CAN ID to each motor.
The front of the robot is defined as the side where the fuse box is located. Based on this reference frame:
Front Left drive motor → CAN ID 1
Front Left steering motor → CAN ID 5
Front Right drive motor → CAN ID 4
Front Right steering motor → CAN ID 8
Rear Left drive motor → CAN ID 2
Rear Left steering motor → CAN ID 6
Rear Right drive motor → CAN ID 3
Rear Right steering motor → CAN ID 7
To complete this step, you will need a Windows laptop with the REV Hardware Client installed, Wago inline connectors, type-C cable and two 120 Ω resistors.
On the laptop, load the motor configurations from the GitHub repository. There are two configuration files in .json format: one for the drive motor and one for the steering motor. Place these files in the following directory:
Each motor driver has four CAN wires: two yellow and two green. The yellow wires correspond to CAN High, and the green wires correspond to CAN Low.
CAN communication requires two 120 Ω termination resistors placed at the terminal ends of the CAN bus. For this procedure, install both resistors across one set of yellow (CAN High) and green (CAN Low) wires for the motor being configured.
Connect the motor driver to the laptop using a USB Type-C cable. Open the REV Hardware Client; the motor driver should appear with CAN ID 0. Load the appropriate configuration file based on the motor type (drive or steering), then update the firmware.
Note: This process is extremely delicate. Ensure all wire connections are stable and secure, especially during the firmware update.
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