Overview
Develop two-axis servo control using a Nano, joystick and PCA9685 driver. Bring up the logic and joystick before connecting an independently powered servo, then add the second servo with conservative movement limits.
What's included
- 1 × pre-soldered ATmega328P Nano board with CH340C and USB-C
- 1 × pre-soldered PCA9685 16-channel PWM servo driver
- 2 × MG90S metal-gear 9g micro servos
- 1 × KY-023 dual-axis analog joystick module
- 1 × 400-point solderless breadboard
- 1 × 120-piece, 10cm jumper wire set
What you need to supply
A regulated external servo power supply is required and not included; share ground with the controller. Assembly and your own firmware are required. USB-C data cable, computer, mechanical brackets and enclosure are not included. Do not power the servos from a controller GPIO pin.
At a Glance
Specifications and Component References
The table identifies the exact bundled sale units. Open each component manual for its pinout, applicable electrical limits and individual examples. The linked component may have other variants; use the bundled variant shown here.
Pinout and Connection Planning
Use the labelled pins and diagrams in the component references above. The connections below describe signal functions, not a physical header drawing. Select and record GPIO that match your chosen firmware and the exact controller board.
| Part or interface | Connection plan |
|---|---|
| Nano to PCA9685 | Connect the documented I2C SDA/SCL signals, logic supply and common ground. The driver logic supply and servo-power input have different roles. |
| Joystick to Nano | Connect the joystick's labelled power, ground and X/Y outputs to the corresponding supply and analog inputs selected in your firmware. Configure the switch input only if you use it. |
| PCA9685 servo power | Provide a regulated external supply suitable for the exact servos and load. Share its ground with the controller; do not power servos from controller GPIO. |
| Two MG90S servos | Check each connector's ground, positive supply and signal orientation against the driver labels. Connect to two deliberately selected channels. |
Wiring Guide and First Checks
- Check that there are two MG90S servos, one Nano with CH340C and USB-C, one pre-soldered PCA9685, one joystick, one 400-point breadboard and one 120-piece 10cm wire set. Supply the external servo supply and your own computer, data cable and firmware.
- Program the Nano alone. Test the joystick's X/Y readings using its manual, without servo power connected.
- Connect the PCA9685 logic side and test I2C communication. Match the driver address and selected Nano bus pins in your program.
- With all power disconnected, wire a regulated external servo supply to the correct servo-power input and join grounds as documented. Keep servo power out of controller GPIO. Avoid routing servo current through breadboard contacts not rated for it.
- Connect one unloaded servo and test a conservative center position and small movement range using the servo and driver documentation. Keep hands and loose parts clear; stop if the servo binds, buzzes continuously or overheats.
- Add the second unloaded servo on a different channel. Map joystick inputs in your own firmware, set conservative endpoints and test before fitting mechanical brackets or applying a load.
Check the result
Confirm stable controller operation, expected joystick readings, reliable driver detection and conservative unloaded motion for each servo. Recheck the external supply under the intended load before attaching a mechanism; a working unloaded demonstration does not establish load capability.
Troubleshooting
| Symptom | Check |
| Nano resets when a servo moves | Inspect the external servo supply, wiring and shared ground. Servo load must not be supplied by a GPIO pin or an unsuitable controller power path. |
| Servo is at an endpoint or buzzes | Remove servo power and check connector orientation, commanded range, driver timing and mechanical binding. Start with a smaller movement range and no load. |
| Joystick seems reversed | Check which X/Y analog input is assigned in firmware and the direction mapping before attaching a mechanical load. |
Code Examples and Firmware
Start with separate Nano/joystick and PCA9685/servo examples from the component references. Your combined program must configure the driver timing, chosen channels, joystick input range and safe endpoints for the actual mechanism. No assembled two-servo robot, brackets or kit firmware are supplied.
The component references describe individual devices. Examples for another controller or a larger project need adaptation; they do not establish that this complete kit has been assembled and tested.
Frequently Asked Questions
Related Tutorials
Use the exact component manuals linked above for individual wiring and software references. When adapting a project tutorial, compare its complete parts list, controller version, power requirements and software settings with this kit before following its instructions.
