After completing the screen selection, we further planned the overall hardware design scheme for SensorCam P4, which roughly includes the following components:

The handle contains batteries. Next, I will elaborate on our selection considerations and final decisions regarding the mainboard, control components, power supply system, and other aspects.

1.  Base Board

After the screen model was selected, we found that there were compatibility challenges between the ESP32P4 chip and the originally planned display screen. After evaluating various aspects such as the form, interface, and performance of the main board, we finally chose an ESP32P4 development board integrated with a 3.4-inch touch display screen as the core main board, as shown in the figure below:

This development board has the following advantages:

● Compact design: The core board is small enough to save valuable space.

● Rich interfaces: Provides a variety of peripheral interfaces with strong expandability.

● Communication capability: Onboard ESP32C6MINI module, supporting WiFi connection.

● Excellent display performance: 800×800 high resolution, 70% NTSC wide color gamut, 300cd/m² high brightness.

● Form fit: The shape design meets the ergonomic requirements of a handheld magnifying glass.

This motherboard not only solves compatibility issues, but its highly integrated design also greatly simplifies our system architecture and reduces the overall complexity.

2.  knob

Why are physical knobs still needed in the touchscreen era? Because we recognize that for fine operations (such as image zooming, parameter adjustment, and menu navigation), the tactile feedback and precise control provided by physical knobs are difficult for touchscreens to replace. The knob we chose is the EC11, as shown in the figure below:

The EC11 knob has the following characteristics:

● Suitable size: The diameter and height conform to ergonomics, ensuring comfortable operation.

● Exquisite appearance: The metallic texture is consistent with the overall style of the device.

● High performance: High sensitivity and accurate scale feedback.

● Economy: Extremely high cost performance and stable market supply.

The EC11 knob will provide users with an intuitive parameter adjustment experience, and it performs exceptionally well especially in scenarios that require quick and precise adjustments.

3.  Buttons

Although equipped with a touchscreen, we firmly believe that physical buttons still have irreplaceable value in specific scenarios: for quick operations, blind operation needs, and providing clear physical feedback.The buttons we chose are five-wire circular keyboard modules, as shown in the figure below:

The five-line circular keyboard module has the following advantages:

● Reasonable layout: The circular arrangement conforms to the natural movement trajectory of fingers.

● Excellent touch: The keys have a crisp sound and clear feedback.

● High sensitivity: Fast response with no sense of delay.

● Ergonomic design: The key travel and pressing force have been optimized, making it not easy to get tired during long-time operation.

These buttons will serve as a supplement to touch operations, providing users with more diversified options for interaction methods.

4.  Battery

To meet the requirement of long-term use of portable devices, we have chosen a 5600mAh 5V lithium battery as the power solution for the following reasons:

● High energy density: 5600mAh capacity ensures that the device can work continuously for a long time.

● Stable output: 5V output voltage perfectly matches the device requirements.

● Reusable: Supports repeated charging and discharging, economical and environmentally friendly.

● High safety: Built-in protection circuit to prevent overcharging and over-discharging.

5.  Summary

Our hardware selection follows the following principles: 

● balancing performance and power consumption

● optimizing user experience

● and ensuring system stability. 

The ESP32P4 development board serves as the core, combined with the EC11 knob, circular keyboard, and large-capacity lithium battery, together forming a complete and efficient hardware ecosystem. This design scheme not only meets basic functional requirements but also achieves a good balance in terms of interactive experience and portability. Next, we will design a suitable casing for the SensorCam P4 based on the form of these hardware components.