15 - System Integration

This week, we will document how all the components (mechanical and electrical) will be integrated together to complete our final project. It's worth noting that many mechanical components still need to be manufactured or designed, but a connection and assembly plan is in place.

BOM and costs

The components to be used are then listed, as well as the number of elements, which are likely to increase throughout the project.

Product Features Quantity Cost Link
XIAO RP2040 Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz.
Support Micropython/Arduino/CircuitPython		 1 $8.49 Amazon
Servomotor Mg995 Torque at 6V 12kg/cm, 7.2V 13kg/cm. 2 $13.99 Amazon
Micro servomotor mg90s Stall Torque: 2.0kg/cm(4.8V) 7 $13.99 Amazon
Servo driver - pca9685 I2C communication
control 16 free-running PWM		 1 $12.99 Amazon
DFPlayer Mini MP3 Serial port 1 $7.96 Amazon
S-25-12 Switching Power Supply AC/DC Single Output 12V 2.1A
1 $39.20 Amazon
Silicone Rubber - Dragon Skin Mix ratio of 1A:1B by Volume
Pot life of 25 minutes
Cures to Soft, Super-Strong, and Stretchy Shore 		1 $38.12 Amazon
PLA Filament




ELECTRICAL - MECHANICAL CONNECTIONS

Component Type Input From Output To Communication
XIAO RP2040 MCU Qt Interface MP3-TF-16P
PCA9685		 Serial
S-25-12 Switching Power Supply
AC/DC 		Power Supply AC PCA9685 -
MP3-TF-16P Actuator XIAO RP2040 Speaker UART
PCA9685 Controller XIAO RP2040 Servomotors I2C
Servomotors Actuator PCA9685 Physical Movement PWM

ELECTRICAL STAGE

As seen in the image, the original board was modified. A voltage regulator was installed in case it needs to be powered externally, and optocouplers were added in case it is necessary to move power stages. As can be seen, all pins of the XIAO RP2040 are placed with a pin header. Although the original project does not need so many pins, they were added because it is conceived as a modular element to which additional elements can be incorporated in the future. Furthermore, it is observed that the XIAO is mounted on a base, in case it is damaged or if it is decided to change family, in this way its installation or replacement is easy and accessible, without the need to disconnect pins or disassemble the designated place for the plate.

As seen in the following figure, the PCA9685 module connects directly to the servomotors to control them. Since the head structure is small, no extensions are needed to connect it to the servomotors. All you need to do is strategically place all the connections and secure the cables to keep them in place. Similarly, the PCA9685 module and the XIAO are connected using a DuPont cable.




MECHANICAL STAGE

Our model was based on a Styrofoam figure, which was scanned in week 5.

This model was worked on in "SolidWorks".
A casting was made to be able to include mechanical elements to the structure.
Within this structure, different mechanisms will be made, such as the eyes shown in the following figure.
Finally, using the Molding and Casting week , we proceeded to make the skin of our animatronic.
There's still much work to be done. For example, there are still bases to be placed along the structure to secure and support it. In addition, internal elements must be installed to mount the servomotors and the mechanisms that perform the movements.




MATERIAL STRUCTURE

The following image illustrates the layout of the electromechanical components. It's worth noting that the base includes the power supply and provides support for the entire structure.




Learning outcome

This week we planned the integration of all our components. Distribution and planning are key elements to ensure the success of this process.