Portable 4G SIM Bonding Device

@danish2051

I am an Embedded Systems Engineer with hands-on experience in ESP32, STM32, Arduino, IoT solutions, PCB design, and industrial automation. I specialize in developing complete hardware and firmware solutions from concept to production. My experience includes sensor integration, wireless communication, data logging systems, Ethernet and Wi-Fi connectivity, MQTT communication, cloud integration, and custom PCB development. My expertise includes: • ESP32 Firmware Development • STM32 Firmware Development • Arduino Projects • PCB Design using Altium Designer • IoT Solutions (Wi-Fi, BLE, Ethernet, MQTT) • AWS IoT Integration • Sensor Integration and Calibration • Data Logging Systems • Industrial Automation Projects • Embedded Linux Development • Serial Communication (UART, RS485, Modbus) • I2C, SPI, CAN Bus Development • Product Prototyping and Testing Recent project experience includes: • ESP32 Ethernet-based monitoring systems • BLE sensor networks with multiple wireless nodes • Engine dynamometer data acquisition systems • Industrial pressure, temperature, RPM, and level monitoring systems • MQTT-based cloud monitoring solutions • Custom PCB design and manufacturing support I focus on delivering reliable, well-documented, and production-ready solutions while maintaining clear communication throughout the project.

@alluankit01

Hi, I can help develop the portable 4G SIM bonding prototype with multi-SIM LTE connectivity, IPSec VPN tunneling, web management UI, enclosure planning, and full handover documentation. The best solution is to build this in a practical prototype phase using OpenWrt/Yocto-compatible hardware, multiple LTE modems, strongSwan IPSec, bonding/failover logic, and a lightweight dashboard showing per-SIM signal, throughput, VPN status, and link health. I’m comfortable with embedded Linux, OpenWrt, LTE modem integration, SIM failover, IPSec/strongSwan, VPN routing, web UI/CLI tools, PCB/enclosure planning, antenna selection, power management, network testing, and technical documentation. Deliverables include: * Hardware architecture * SIM/modem integration plan * Battery/power design notes * IPSec VPN setup * Link bonding/failover logic * Web UI for status monitoring * Firmware/source handover * Throughput/latency test logs * Quick-start guide * Validation report Prototype parts, LTE modules, antenna, battery, PCB fabrication, and enclosure costs can be confirmed separately before purchase. Best regards Ankit

@jb095

As an embedded systems engineer and PCB designer, I not only understand the technical nuances of this project, but I also bring over a decade of experience which aligns perfectly with your requirements. My proven track record in handling all stages of electronic device design - from concept to production - supports my ability to provide you with a comprehensive and successful solution for your portable SIM-bonding unit. Some key areas where I can add immense value to your project include my expertise in high-speed PCB design, precisely matching impedance for reliable signal performance at various frequencies -- a critical requirement for your high-bandwidth connection. Additionally, my proficiency in RF and antenna design is directly applicable to IPSec VPN tunneling through multiple 4G LTE links, thus enhancing the overall efficiency of your solution. Furthermore, my specialty in firmware development for IoT devices involving BLE, LTE (including SIM card interface), GPS and various sensors equips me with the skills necessary to meet your criteria seamlessly. These skills revolve around low-power optimization and high-precision sensor acquisition, complementing the portable nature of the device you require.

@shaxzodj

Hi, I have experience with Linux networking, VPNs, embedded Linux (OpenWrt), and LTE-based networking solutions. Your project is ambitious, and I'd be happy to help build a reliable prototype. Before we proceed, I have a few questions: * Do you already have a hardware platform/modem in mind (Quectel, Telit, Sierra, etc.), or should I select one? * Do you need true packet-level bonding, or is session/load balancing acceptable? * Will you provide the IPSec VPN server, or should I configure both client and server? * What is your expected budget and target timeline for the prototype? Looking forward to discussing the details and finding the best approach for your project.

@rfandelectronics

In an increasingly connected world, where seamless and fast internet connectivity is a necessity, a portable 4G SIM bonding device is essential. My team and I, Radionica RF & Electronics Engineers, can bring your vision for this project to life. With our specialization in high-frequency systems, microwave engineering, and RF design coupled with deep expertise in embedded systems development, we are the perfect fit for this task. Our proficiency in using tools like OpenWrt and Yocto for firmware and KiCad/Altium for PCB design vastly aligns with the preferred toolchain you’ve mentioned. This compatibility, along with our extensive skill set in aspects like real-time link aggregation, IPSec implementation, and cellular failover will guarantee a successful execution of the project. Moreover, our commitment to high standards and meticulous attention to detail means that we won't just focus on developing a working prototype but on ensuring it's robustness through thorough validation during lab tests. We believe that a continuous collaboration with you through weekly progress calls will keep the project aligned with your expectations until we deliver a tested prototype alongside comprehensive documentation and deliverables

@eternitech

Hi, New on Freelancer — 20 years of development experience behind us. We're taking our first few projects here at a fraction of our normal rate purely to build our review history. You get senior agency work at junior pricing; we get a review. Straight trade. integrating multiple 4G LTE links into a cohesive unit often requires careful attention to the load balancing algorithm to ensure optimal bandwidth distribution. I'd start by examining the firmware's capability to handle dynamic link management and IPSec VPN tunneling. What's your target date for having the prototype ready for testing?

@bohdanb12

Hi I can help you develop the portable four-SIM bonding unit as an integrated hardware, Linux firmware, management and validation platform. The key technical issue is that four local LTE connections cannot provide true packet level bonding without a remote aggregation endpoint that reorders traffic and presents one stable public connection. I would solve this with a companion bonding gateway, multipath tunnels over independent LTE modems, intelligent scheduling, and an IPSec policy designed around the aggregated path. The hardware will include four SIM interfaces, suitable LTE modules, isolated RF paths, carefully positioned antennas, power sequencing, thermal management and protected battery charging. The management interface will provide throughput, signal, modem, tunnel, failover, logging, configuration and signed firmware update controls. I will deliver the prototype, design sources, software, gateway configuration, manufacturing documentation, and test evidence covering bandwidth, mobility, failover, latency and packet loss. Thanks, Bohdan Question Will you provide the remote bonding server? Which countries, carriers, and LTE bands must be supported? What battery runtime and enclosure size are required? Should IPSec terminate at the bonding gateway or another VPN endpoint?

@shriramh6

I have lots of experience in 4g lte module I have build these kind of models more so I hope if you provide this job to me it would be more helpful Thank you

@paulpham93

I will design your portable 4G SIM bonding device, including schematic design, PCB layout, antenna integration, and stable firmware development. I have extensive experience in cellular communications and embedded systems, ensuring a high-performance, compact hardware solution for you. Let's discuss your specific network security and size constraints. Best regards, Paul