Prototype Wearable Contactless Payment Device

@Mahihassi

As a dedicated Electrical Engineer and Master's graduate specialized in Embedded Systems, I believe I have the perfect skill set for your wearable contactless payment device project. My experience with various microcontrollers like STM32, ESP32, TI Tiva, NXP LPC, and more aligns perfectly with your need for RFID/NFC expertise. Not only have I designed PCBs tailored towards IoT and RF hardware but have also optimized firmware to ensure smooth communication between different modules like DMA or wireless stacks such as BLE, WiFi, LoRa. Moreover, my proficiency in AI and Machine Learning can further enhance your product by incorporating intelligent algorithms for edge devices yielding precise control and effective data analysis. This could be invaluable in fine-tuning the balance management system of your contactless card.

@markoa7

Hi, I'd be happy to help develop the wearable hardware prototype. I have experience with embedded systems, NFC/RFID interfaces, ESP32-based designs, cellular modules, and custom PCB development. For the wearable, I would recommend an ESP32-S3 paired with an NFC controller (such as the PN532 or ST25R series) and a compact LTE Cat-M/NB-IoT module with an integrated SIM. One important point: a standard mobile banking app cannot directly top up a proprietary NFC card unless the card, backend, and banking/payment infrastructure are designed to support that workflow. I can help design the hardware, firmware, card application, and communication protocol, but the payment ecosystem will need to be clearly defined. Could you clarify: 1. Is your proprietary card already developed, or does it also need to be designed? 2. Which SIM network and cellular module do you prefer? After reviewing these details, I can provide a fixed-price quote, timeline, and manufacturing package for the prototype.

@tshibsamuel477

Hi there, I read your offer carefully and understand that you need a practical wearable payment proof-of-concept with touchscreen, RFID/NFC card reading, SIM-enabled transaction forwarding, demo cards, firmware, schematic, BOM, and manufacturing notes. I can support the hardware architecture, RFID/NFC reader integration, SIM/LTE module, touchscreen UI, transaction logging, balance read/write flow for your authorized proprietary cards, source code, wiring/schematic files, and prototype documentation. My background in embedded systems, ESP/ARM-based hardware, RFID/NFC integration, IoT connectivity, battery-powered devices, and prototype development fits this project well. I would also make sure the design is handled in a secure and compliant test environment. Just send me a message and we can discuss the chipset, prototype cost, and first working unit timeline. Best regards, Samuel Tshibangu

@leonidye

Hi, Your concept is interesting, but there are a few technical considerations that should be addressed before development. A wearable device can certainly integrate an RFID/NFC reader, touchscreen, cellular module (LTE/NB-IoT), and embedded controller. However, a card cannot be topped up directly from a standard mobile banking app unless it participates in a supported banking or payment ecosystem. If the card is truly proprietary and stores its own balance, the top-up process will require a backend service or dedicated application to securely write the new balance to the card. I can develop a proof-of-concept wearable using an ESP32 or ARM MCU with an NFC/RFID reader, SIM-enabled communication module, touchscreen interface, and rechargeable battery. The prototype will demonstrate card authentication, balance reading/updating, transaction logging, and secure transmission of transaction data to your cloud server. I will also provide the complete schematic, PCB files, firmware source code, BOM, and manufacturing documentation. For the first milestone, I recommend delivering a functional proof of concept consisting of one wearable device and two programmable RFID/NFC cards, together with a demonstration application showing balance updates and transaction reporting. Once the concept is validated, we can evolve the design into a production-ready version with enhanced security, certification, and payment integration. Regards,

@yaroslavmark

Hi, I have 12+ years of experience in embedded hardware and firmware development, delivering 40+ production-ready IoT devices using ESP32, STM32, RFID/NFC, LTE/Cellular modules, touch displays, and battery-powered embedded systems. I have designed secure wireless devices with custom PCBs, low-power architectures, and complete manufacturing documentation from prototype through production. Approach ✅ I will review your card protocol and system requirements, recommend the optimal MCU, RFID/NFC chipset, touchscreen, and SIM module, then define a reliable hardware architecture for the wearable prototype. ✅ I will develop the schematic, compact PCB, firmware, and communication interface, ensuring reliable RFID transactions, cellular data forwarding, and a responsive touchscreen with clean, maintainable code. ✅ I will validate the prototype, prepare the manufacturing package, and deliver the source code, schematic, BOM, and documentation for future production. Questions ✅ What RFID/NFC technology and communication protocol does your proprietary contactless card use (ISO 14443, ISO 15693, MIFARE, DESFire, or custom)? ✅ Will you provide the card specifications, authentication method, and APIs required to read and update the card balance? ✅ Do you have preferred touchscreen size, wearable dimensions, or SIM module requirements for the first prototype? Best, Yaroslav

@tetianam8

⭐⭐⭐⭐⭐ I've carefully reviewed your project, and I can develop a compact proof-of-concept wearable that combines RFID/NFC, a touchscreen, and a SIM-enabled communication module into a portable device suitable for demonstrating your payment concept. For the prototype, I'll recommend a reliable MCU platform (ESP32-S3 or STM32, depending on performance requirements), an NFC/RFID chipset such as the PN532 or ST25 series, and a compact LTE/NB-IoT module with an integrated touchscreen interface. The firmware will securely read the card, process balance updates according to your protocol, display the current balance, and transmit transaction data over the cellular network. Deliverables: • One fully functional wearable prototype • 1–2 programmed RFID cards for testing • Complete schematic, firmware, BOM, and manufacturing files • Documentation and demonstration video • Production guidance for future revisions Proposed Milestones: Hardware architecture & schematic Prototype assembly & firmware Transaction testing & SIM communication Final documentation and handoff Before we begin, I'd like to review your proprietary card protocol and top-up architecture. If the card is intended to be reloaded from a standard mobile banking app, we'll need to ensure the backend/payment integration supports that workflow so the prototype behaves exactly as you expect.

@julianm260

As you pinpointed, this project fits precisely within my sphere of expertise: senior electronics engineering with a focus on RF engineering and embedded systems. In my 8 years in the industry, I've successfully designed and delivered hardware solutions similar to what you're demanding for your prototype wearable contactless payment device. My background in circuit design, PCB layout and firmware development lends a strong foundation to the specific challenges of your project. Furthermore, I've a proven track record of handling projects right from their conception through design, validation, documentation and final implementation. I deeply value compliance with safety, reliability and performance standards and my effective troubleshooting skills help me integrate complex systems assuring high-quality results under tight deadlines. Lastly, I'm well-versed in the core technologies required for this project such as RFID/NFC, ARM microcontrollers and the ESP-n series that use embedded Linux. Given such experience, I can efficiently design power converters, RF modules <HTMLInputElement>and manage electrical distribution system for compact wearable devices like what you require. I am ready to provide the single practical working sample that you need along with a detailed schematic and programming for the manufacturing process! Let's get started towards an exciting Milestone One!

@azraazeen9

As an Electrical Engineer with a rich background in Electronics and PCB Layout, I believe I am the perfect fit for your prototype wearable contactless payment device. I have extensive knowledge and experience working on projects that include RFID/NFC, ARM, and embedded-Linux which are directly aligned with the requirements of this project. Moreover, my skill set also extends to AI and 3D modeling which can prove valuable throughout the design process. I understand that a functioning proof-of-concept is vital for this project, and I assure you of my intricate attention to detail and strong problem-solving abilities. With my expertise, I will deliver not only a fully assembled wearable but also comprehensive documentation including schematics, source code, BOM, wiring files you can further utilize. I have a strong commitment to client satisfaction and effective communication, qualities which have helped me provide my previous clients with successful outcomes. I will actively involve you in each stage of the development process providing clear updates. Choose me for this project and let's create a wearable payment device that's portable, efficient, and secure.

@engrfarooq04

Hello, I have extensive experience in **Electronics, Embedded Systems, PCB Layout, Firmware Development, and Payment Processing**, making me well-suited for this prototype. I will develop a compact wearable using an **ESP32-S3/STM32**, **PN532 or ST25R NFC/RFID controller**, and a **SIM7600/SIM7080 cellular module** for secure transaction forwarding. The solution will include custom PCB design, embedded firmware, touchscreen interface, RFID card communication, and API integration for transaction logging. I will deliver **two programmed RFID cards, one fully assembled wearable prototype, complete source code, schematics, BOM, manufacturing files, and technical documentation**. The firmware will be clean, modular, and scalable for future production. I can also provide a demonstration video, testing results, and post-delivery support to ensure the prototype performs reliably and meets all specified acceptance criteria.

@nemanjam61

Hello, I would base the wearable on an ESP32‑S2 module paired with a PN532 RFID/NFC front‑end and a secure element (e.g., ATECC608A) to store the card balance locally, ensuring the UI stays under 200 ms even on a cold start. The SIM‑enabled LTE modem (like Quectel EG91) will send transaction logs directly over MQTT, so the device remains autonomous without external peripherals. To avoid race conditions when multiple taps occur in quick succession, I’ll implement a double‑buffered balance update in firmware and lock the NFC session until the SIM transmission confirms receipt. Which RFID chipset do you prefer for the wristband prototype? Thanks. Nemanja

@alluankit01

Hi, I can build a closed-loop proof-of-concept wearable payment demo with RFID/NFC card reading, balance update logic, touchscreen display, SIM-based transaction forwarding, firmware, schematic, BOM, and test documentation. The best solution is to first define whether this is a private stored-value demo card system or a regulated live payment product. For the prototype, I would use an ESP32/STM32-class controller, RFID/NFC reader, small touchscreen, SIM module, rechargeable battery, and demo cards where balance can be read, debited, and verified after multiple taps. I’m comfortable with embedded systems, RFID/NFC modules, touchscreen interfaces, SIM/GSM communication, firmware development, PCB/schematic design, stored-value demo workflows, API communication, and prototype testing. Deliverables will include: * One working demo device design * 1–2 sample demo cards * RFID/NFC balance read/write logic * Touchscreen balance display * SIM transaction forwarding * Firmware source code * Schematic and wiring files * BOM and manufacturing notes * User guide and demo video I’ll focus on a practical, testable prototype. For real banking app top-ups or public payment use, I would clearly separate the compliance, payment-processor, EMV/PCI, and certification requirements. Best regards Ankit

@Cruz1217

One hidden issue is that the card’s balance can drift if the wearable powers down before the debit is fully written. I’ll add a tiny super‑capacitor backup so the last read value survives a brief power loss and gets reconciled on restart. The prototype will run on an ESP32‑S2 for NFC, a SIM800L for cellular, and a 1.3‑inch OLED to display the updated amount. Another frequent mistake is transmitting the transaction before the card confirms the write, which can lead to duplicate charges. Thus I’ll buffer the transaction in FRAM and only push it after receiving the card’s ACK, and I’m ready to start immediately.

@oleksandrn28

✅✅✅✅Hi, there.✅✅✅✅ Your project for a compact wearable that accepts payments and communicates with your proprietary contactless card aligns perfectly with my experience in RFID and embedded systems. I can deliver a fully functional prototype within your specified timeframe with 100% accuracy. I'd love to discuss further details and provide you with samples of my previous work. This project involves creating a portable wearable device that reads, debits, and displays the balance on a touchscreen, communicates with the card over RFID, and has an embedded SIM module for transactions. I am confident in my ability to deliver a reliable prototype that meets your requirements, showcasing my expertise in RFID/NFC and embedded system development. I look forward to the opportunity to work together and bring your vision to life. Best Regards, Oleksandr

@irfanui

I reviewed Prototype Wearable Contactless Payment Device as a robotics/vision engineering requirement with real hardware or simulation acceptance criteria. I can structure the ROS/ROS2 nodes, topics, services and launch configuration; integrate perception using OpenCV/YOLO; connect sensors or arm controllers; and provide reproducible setup, tests and demonstration evidence. My approach is to establish the target environment and measurable success condition first, then validate each perception, planning and control component independently before end-to-end testing. Please share the robot/simulator, ROS distribution, sensors and expected output so I can propose the exact architecture. Portfolio: https://www.freelancer.com/u/irfanui Regards, Mohammad 4th Dimension Partners

@heenafullstacken

I would approach Prototype Wearable Contactless Payment Device as a measurable robotics system, with perception, communication, and control validated separately before the complete demonstration. I can develop the ROS/ROS2 package structure, integrate sensors or actuators, build OpenCV/YOLO perception, prepare launch and configuration files, and supply repeatable setup and test instructions. To recommend the right package design, please tell me the ROS distribution, target robot or simulator, available sensors, and the exact behaviour that will mark the project successful. Robotics profile: https://www.freelancer.in/u/heenafullstacken Kind regards, Heena | A Plus IT House

@arturg6

Hello, "WEARABLE CONTACTLESS PAYMENT PROTOTYPE" — you need a tiny wristband that can read your card, debit it and show the balance. I’ll base the hardware on an ESP32‑S2 MCU paired with a PN532 NFC module and a SIM800L cellular board. The ESP32‑S2 gives enough flash for the UI and can run FreeRTOS, keeping the UI responsive while the SIM module sends transaction data in the background. This choice lets us keep the device under 30 g and fit a 1.3‑inch TFT touchscreen. To ensure the card’s balance stays accurate, I’ll implement atomic read‑modify‑write on the ISO‑14443 tag and add a watchdog that re‑reads the balance after each tap, preventing missed updates if the network is momentarily slow. Do you have a preferred NFC chip model or should I source the PN532 for the prototype? Looking forward to working with you. Artur Giżycki

@maksymstel

Okay, I got what you want exactly. I am a Full Stack Engineer Embedded Engineer, PCB Designer, and RF Engineer with 10 years of experience, providing RFID/NFC systems, ESP32/ARM embedded development, LTE/NB-IoT integration, touchscreen interfaces, and custom wearable hardware. In my opinion, the fastest way to build a proof-of-concept is to use a modular architecture with an NFC/RFID reader, a low-power MCU, a compact LTE module with SIM support, and a touchscreen. This allows rapid validation of the hardware while keeping the design scalable for a future custom wearable PCB. This project is very similar to my previous works. I have developed secure RFID/NFC devices, IoT wearables, LTE-enabled embedded systems, and custom PCBs with battery management and touchscreen interfaces. My work covers hardware design, firmware, prototype assembly, and production-ready documentation. ✅ So, I will divide your project into three major steps. 1️⃣ Design the wearable architecture, select the RFID, MCU, LTE, and display components, and prepare the schematic. 2️⃣ Develop the firmware, integrate the touchscreen and cellular communication, and validate the prototype hardware. 3️⃣ Deliver the prototype, source code, schematic, BOM, manufacturing files, and demonstration video. Via private chatting or meeting, I can also provide a detailed development schedule, prototype cost, and manufacturing plan. Best regards. Maksym

@nutankumarftp

With my decade of full stack development experience, I am confident in my ability to create your prototype wearable contactless payment device. I am particularly skilled in API development, which will be especially valuable for this project as it requires communication between the contactless card, the wearable device, and the mobile-banking app for top-ups. My expertise extends from the frontend touchscreen design and RFID reader to the backend SIM module, ensuring smooth transaction processing and instant balance updates. I have a deep understanding of client requirements and minimal back-and-forth is ensured throughout the project. My technical expertise across modern web technologies such as JavaScript, React.js, API design and integration, and ARM make me readily familiar with the primary functions required for this project. A quick turnaround time is one of my strengths without any compromise on quality. With me on board, you won't just be receiving 1-2 cards sample or one device rather you will get a complete manufacturing process wrapped up nicely with an easy-to-follow schematic, detailed programing guide and even a short video proving charge and spend cycle, all aligned to your needs. Choose me for a reliable yet innovative execution of your prototype that will keep your balances right and transactions swift from feed to tap. Let's collaborate to create an efficient solution together!

@Glexy111

Hello, I have seen your are looking embedded payment device developer working in RFID, Embedded Systems and Firmware Development I am having 7 years of experienced as embedded systems developer and I will work according to your features list. Please share more details of your project in chat. Looking forward to your response Thanks