DESIGN

The Raspberry Pi and the 5-inch display enclosure were kept the same for this project's design; we simply removed the battery pack circuit and the back lid from the model before adding the 3D model of the SMPS.

We wanted to reuse the existing enclosure, so we designed a second body that connects the enclosure from the bottom using two M3 nuts and bolts. This new case keeps the SMPS circuit in location. We added the SMPS AC socket to the model on the right side, where we opened the I/O ports.

Furthermore, we've also used the existing slightly tilted stand, which will be mounted on the bottom side of the SMPS enclosure with four M2 screws.

On the back side, we've incorporated a Lid part that unites or links both enclosures to form a single body. We've put mounting holes all over the Lid parameters, where we'll use M2 screws to connect the lid and enclosure.

From the front, we modeled another component that will be put on the second enclosure to improve the model's aesthetic.

After finalizing the model, we exported the mesh files and 3D printed them on an Ender 3 using a 0.4mm nozzle and 0.2mm layer height.

POWER CIRCUIT

To power the Raspberry Pi and display arrangement from the battery pack circuit we are using, which is an 11.1V 3S Lithium cell battery pack setup, we needed a Buck converter board that would step down the 11.1V to a stable 5V to run the Raspberry Pi and display.

To address this issue, we selected a Buck Converter setup that includes the IP6505 IC, a step-down converter with an integrated synchronous switch capable of handling an output of up to 10 A for fast charging protocols.

The IP6505 features an integrated power MOSFET with an output voltage range of 3V to 12V and an input voltage range of 10.5V to 28V. It can provide up to 24 W of output power by automatically adjusting the voltage and current in line with the recognized quick charge protocol, more than enough for our Raspberry Pi 4 and display setup.

The schematic was initially created and customized following the datasheet's example layout.

http://www.injoinic.com/wwwroot/uploads/files/20200220/f11cf889f6261e26dcaf52164367c836.pdf

All of the components on this board are surface mount, which reduces the need for manual soldering.

HQ NextPCB Service

After completing the PCB design, we export the Gerber data and send it to HQ NextPCB for samples.

Gerber Data was sent to HQ NextPCB, and a Green Solder Mask PCB with White Screen was ordered.

After placing the order, the PCBs were received within a week, and the PCB quality was pretty great.

In addition, I have to bring in HQDFM to you, which helped me a lot through many projects. Huaqiu’s in-house engineers developed the free Design for Manufacturing software, HQDFM, revolutionizing how PCB designers visualize and verify their designs.

HQDFM: Free Online Gerber Viewer and DFM Analysis Tool

Also, NextPCB has its own Gerber Viewer and DFM analysis software.

Your designs are improved by their HQDFM software (DFM) services. Since I find it annoying to have to wait around for DFM reports from manufacturers, HQDFM Is the most efficient method for performing a pre-event self-check.

Here is what the online Gerber Viewer shows me could not be clearer.

However, for full function, like DFM analysis for PCBA, you need to download the software. The online version only provides a simple PCB DFM report.

With comprehensive Design for Manufacture (DFM) analysis features, HQDFM Is a free, sophisticated online PCB Gerber file viewer.

It provides insights into advanced manufacturing by utilizing over 15 years of industry expertise. You guys can check out HQ NextPCB if you want great PCB service at an affordable rate.