With all mechanical parts assembled, we moved on to the electronics.

We started by laying out all key components:

• 3 Stepper motors: one for the sphere rotation, one for the curved rail cart, and one for the rotating capture zone

• 1 Linear actuator: to extend and retract the gripper

• 2 Servos: one for rotating the actuator and one for opening/closing the gripper

• 3 limit switches: to detect home positions and aid with calibration

• ESP32: our main microcontroller handling motion sequences and interface control

• Motor drivers: 1 DRV8871, 1 Makerbase MKS SERVO42D, 2 Makerbase MKS SERVO42C

• Power supply : 12V power supply, 5V buck converter

• 1 Nextion

We then went on to make the circuit diagram

We also planed to add integrated: a custom controller composed of two push buttons, which allows us to jog the orb manually.

Another interesting part appears in the top left corner of the diagram—the relay connected to the actuator. This section of the circuit is our workaround to detect when the linear actuator is fully retracted. Since the actuator includes an internal limit switch , we decided to solder wires directly to the actuator motor terminals. This setup lets us monitor the voltage across the motor and use a relay to detect when the current drops—indicating that the actuator has hit its internal stop.

Then, we laid out all the components across multiple perf boards to visualize how we wanted to organize the circuit layout.

Once we were satisfied with the arrangement, we began the soldering process.

Another major task was creating the cable bundle that connects the main circuit to the moving cart on the rail. To do this, we positioned the cart at its furthest point and measured out the cable lengths accordingly to ensure proper reach.

To allow for easy disassembly and maintenance in the future, we decided not to solder the cart’s cables directly to the circuit. Instead, we used a 16-pin connector like this one:

We then connected the cart's wires to the male connector and matched them with corresponding wires going to the circuit on the female connector. This was the final cable assembly:

Finally, we installed all the electronics into the base of the system—and with that, the electronics assembly was complete!