Firmware Developer Needed for Sauna Control Hardware (Mobile App Integration)

@noumanmehtab86

Hello, i have 18 years plus experience in developing hardware and firmware . i have worked intensively on stm32, nordic nrf series, esp32 pic avr mbed series . please share ur hardware information so that i can help u to develop the firmware.

@macroenergy

With over a decade of experience as an embedded systems engineer, I have honed my skills which make me a perfect fit for your project. Not only I am familiar with developing firmware using Embedded C/C++, but also comfortable with microcontrollers such as ESP32, STM32 and Nordic. Furthermore, my previous projects involved working with Bluetooth Low Energy (BLE) and WiFi communication, which will come very handy in integrating your sauna control device with the mobile app. One of my core competencies is building IoT/connected devices, and I've worked on similar projects involving temperature monitoring and control mechanisms. Additionally, I'm highly skilled with different hardware communication protocols (UART, I2C, SPI), essential to ensure secure and efficient communication between the device and the mobile apps.

@amelectronics

Hi, I have experience in designing Circuits and can complete your project. I have expertise in the following: 1- Designing schematic and PCBA 2- Ordering the PCBA and getting boards manufactured. 3- Writing firmware for the PCBA to make sure everything works as expected. 4- I can also develop smartphone apps to communicate and control the hardware. If you wish we can discuss in chat. Thank you.

@markoa7

Hi there, I’ve reviewed your sauna control hardware and the need for robust embedded firmware tightly integrated with a mobile app. I’ll implement reliable real-time control for temperature, timers, and safety features, with a clean BLE/WiFi communication stack to your iOS and Android apps. The firmware will expose a stable protocol for status updates and command handling, using ESP32 or STM32 platforms as appropriate, with UART/I2C/SPI interfaces to sensors and relays. I’ll deliver a compact, well-documented firmware layer first, then iterate toward full IoT connectivity and remote diagnostics. What are your preferred BLE vs. WiFi integration strategy and any security requirements for the device-to-app channel? Best regards, Marko Aleksic

@electronicsdone

Best Embedded IoT Device Control Expert ⭐⭐⭐⭐⭐ Hi, Thank you for posting your project, “Developer Needed for Sauna Control Hardware (Mobile App Integration).” I’ve reviewed your requirements and can help ensure your device control logic, communication protocol, and mobile connectivity are reliable, stable, and optimized for real-time IoT operation. I bring 11+ years of experience in embedded systems, IoT device development, and hardware–software integration, along with hands-on experience working with microcontrollers such as ESP32, STM32, and Nordic platforms, including BLE and WiFi communication with mobile applications. ✅ How I’ll Help You Succeed 1. Develop reliable embedded software in C/C++ to manage sauna temperature control, timers, and safety mechanisms. 2. Implement stable BLE or WiFi communication between the device and mobile applications (iOS & Android). 3. Create a robust communication protocol for sending device data and receiving control commands from the app. 4. Integrate temperature sensors, relays, and control circuits to ensure accurate monitoring and safe heater operation. ✅ Before I start, one quick question: Which microcontroller platform is currently used on your hardware board (ESP32, STM32, Nordic, or another MCU)? If you share that, feel free to message me, and we can align quickly. Best regards, Prat PCB Must Innovations

@mykolalus

⭐⭐⭐⭐⭐ Senior PCB & Firmware & Data Engineer Here! ⭐⭐⭐⭐⭐ I have checked out your project details and I am confident that I can finish your project perfectly. I have implemented safety-critical control systems including PID-based temperature regulation, heater relay/SSR control, watchdog supervision, thermal runaway protection, and redundant sensor validation. My approach begins with defining a layered firmware architecture: HAL drivers (GPIO, ADC, UART, I2C, SPI), middleware services (BLE/WiFi stack, RTOS tasks), and application logic (state machine for sauna modes, timers, fault handling). For communication, I design a structured GATT profile (BLE) or secure REST/MQTT API (WiFi) with encrypted transport, versioned command protocol, and bidirectional event handling. I ensure deterministic real-time behavior using FreeRTOS task prioritization, non-blocking drivers, and fail-safe recovery mechanisms. Available to start immediately with long-term commitment. Looking forward to discussing more details. Regards, Mykola

@hayat38402

Hi, how are you doing? I went through your project description and I can help you in your project. your project requirements perfectly match my expertise. We are a team of Electrical and Electronics engineers, we have successfully completed 1000+ Projects for multiple regular clients from OMAN, UK, USA, Australia, Canada, France, Germany, Lebanon and many other countries. We are providing our services in following areas:  Embedded C Programming.  VHDL/Verilog, Quartus/Vivado, LabVIEW/ Multisim/PSPICE/VLSI  MATLAB/SIMULINK  Network Simulator NS2/NS3  Microcontroller like Arduino, Raspberry Pi, FPGA, AVR, PIC, STM32 and ESP32.  IDEs like Keil MDK V5, ATmel studio and MPLab XC8.  PLCs / SCADA  PCB Designing Proteus, Eagle, KiCAD and Altium  IOT Technologies like Ethernet, GSM GPRS.  HTTP Restful APIs connection for IOT Communications. Also, we have good command over report writing, I can show you many samples of our previous reports. Kindly consider us for your project and text me so that we can further discuss specifically about your project's main goals and requirements.

@shivkantverma

Hi, Greetings. I am interested to work on your project. Please discuss design details and scope of work. Looking forward to work with you, Thank you shivkant

@ahmedgnisa

Hi there I created many firmware and IoT projects . Please review my profile Fully tested and documented to guide mobile team within 2 days. Stable firmware with self maintain and reconnect. I built many backend and mobile apps so its easy to guide the others. Lets talk and discuss it in detail. Best regards

@Zainrais0786

Are you looking for an experienced Embedded Firmware Developer to program firmware for a sauna control hardware device. Hi, I am Zain. I can easily handle the task including • Embedded Systems • BLE / nrf52 / ESP32 / stm32wb • PCB Design • KiCAD / Altium • Firmware Development • C / C++ • Simulations etc. Lets chat. Best regards

@sivakumar676

─── ⚡⭐⋆☆⋆⭐⚡ ─── Hi, Client please review my last firmware development history: https://www.freelancer.com/projects/embedded-systems/OTA-Dual-Bank-STM-Update/reviews I build production firmware for connected devices, with strong focus on safety logic, stable control loops, and rock solid BLE or WiFi comms. My stack is Embedded C and C++, ESP32 or STM32 or Nordic, FreeRTOS, UART I2C SPI, plus BLE GATT design and API based WiFi messaging. I’ve shipped similar hardware controllers that handle sensors, relays, timers, failsafes, and real time mobile control without random disconnects. Your goal is firmware that safely runs the sauna, reports live status to iOS and Android, and reliably executes app commands. So, I'll: Implement temperature sensing, heater control, timers, and safety interlocks with clear state machine logic and watchdog recovery. Design the BLE or WiFi protocol, add real time telemetry, command handling, and reconnection stability, then deliver clean documented firmware ready for scale. Best, Siva

@Feriver

Hello, I specialize in embedded firmware development for IoT devices and can implement stable, real-time control for your sauna hardware. I have extensive experience programming ESP32 and STM32 microcontrollers in C/C++, integrating sensors, relays, timers, and safety mechanisms while ensuring precise temperature control. I have built BLE and WiFi communication protocols for mobile apps, enabling seamless two-way data exchange for device monitoring, command reception, and status updates across iOS and Android. My approach emphasizes reliability, low-latency response, and clear, maintainable code. I am available to start immediately and can ensure robust firmware that integrates fully with your existing PCB and control logic. This project also aligns with long-term collaboration on similar IoT hardware products. Should the mobile communication prioritize BLE for low power or WiFi for extended range and cloud integration? Are there any specific safety or overheat thresholds that must be hard-coded versus app-configurable? Thanks, Asif

@kaloliyavivek

We are team of experience developers for loT design & products, web development and mobile development. We can make the whole system better to work efficiently. Let's discuss more on call or chat.

@SinzoTechLab

Embedded firmware engineer with solid experience in ESP32 and STM32 platforms, developing IoT control systems with BLE and WiFi connectivity. I have delivered real-time control firmware for industrial boards integrating sensors, relays, heaters, and safety logic. Experience • Embedded C/C++ (bare-metal and FreeRTOS) • BLE (custom GATT services) and WiFi (REST/MQTT/API) • Temperature control loops (PID), filtering, watchdogs • I2C, SPI, UART, ADC integration • Robust state machines with fail-safe design Technical approach • Clean layered architecture (HAL + control + communication) • Deterministic heater control with over-temperature and sensor fault protection • Independent safety logic (timeout, watchdog, emergency cutoff) • Stable bidirectional protocol for mobile app (BLE or WiFi) • Non-blocking task handling for reliable real-time performance Deliverables • Complete documented firmware source • Defined communication protocol • Flashing/build instructions • Basic validation report (temperature stability, communication reliability) Availability: Immediate Estimated timeline: 3–4 weeks Budget: €2,000–€3,000 Open to long-term collaboration on future connected devices.

@isurutech

Dear Sir, I would like to present myself as a prospective candidate for your project. I have strong knowledge and experience in electronics and programming, including firmware development and Android application development. After reading your project description, I believe I would be a suitable candidate since my skills closely align with your project requirements. As you mentioned that the hardware is already built, I would like to ask which microcontroller is currently being used in your system. 1. I have extensive experience in microcontroller firmware development. If you visit my profile and review my previous projects, you will find a completed project titled “IP-Based Panic Button System,” which is quite similar to your project. That system includes a hardware controller and mobile/web applications connected through the Internet to monitor sensors and control the hardware through Android and web interfaces. 2. I also have significant experience working with Wi-Fi connectivity, including integrating ESP32 devices with mobile applications. 3. Regarding my availability, I can allocate approximately 3–4 hours per day to work on your project. can allocate more if needed. Please note the bid price can change after knowing exact project details. Please feel free to message me if you have any questions. I look forward to your favorable reply. Sincerely, Isuru Athukorala

@yaroslavmark

Hi, I am a senior embedded firmware engineer with 10+ years of experience in Embedded C/C++, delivering 20+ MCU-based products based on ESP32, STM32, and Nordic nRF52, including BLE/WiFi HVAC and industrial controllers with >99% field stability and OTA support. I have implemented BLE GATT services and REST/MQTT APIs for iOS/Android apps, achieved ±0.5°C PID temperature accuracy, and designed fail-safe heater control with watchdogs, brownout detection, and multi-layer hardware interlocks. Approach ✅ I will review the schematic, MCU resources, and sensor/relay interfaces to define a layered architecture (HAL, drivers, RTOS/tasks, application logic) ensuring deterministic real-time control. ✅ I will implement calibrated temperature acquisition, PID-based heater control with safety hysteresis, watchdog supervision, over-temperature shutdown, and secure NVM parameter storage. ✅ I will design a robust BLE GATT or WiFi API protocol with CRC/ack logic, command-state synchronization, and structured payloads for reliable bidirectional communication. ✅ I will perform stress, fault-injection, and long-run validation to ensure stable operation and safe recovery from power or communication failures. Questions ✅ I need to confirm the selected MCU and whether an RTOS is already integrated. ✅ I need details on the temperature sensor type and required accuracy/safety thresholds. ✅ I need to clarify if BLE, WiFi, or dual connectivity is required and whether OTA updates are expected. Best,

@hancho6319

As an experienced Embedded Systems Engineer, my skills and qualifications are directly aligned with your requirements to develop and implement firmware that controls and monitors your custom sauna control hardware device. I've worked extensively with languages like C and C++, microcontrollers such as ESP32, STM32, Nordic, and communication protocols including but not limited to BLE/WiFi. Notably, I have successfully executed various projects involving IoT devices and communication protocols - something that is crucial for this project. I can confidently develop a reliable communication protocol to ensure seamless transmission of data between the sauna control hardware and the iOS/Android mobile app. In addition to my technical expertise, I want to emphasize my deep commitment to working meticulously with sensors, relays, and control circuits. It's worth mentioning that my background in Electrical & Electronics Engineering has helped me gain a profound understanding of these components. If given the opportunity, I am confident in my capabilities to create a sturdy firmware for your current project as well as any future tasks you may have. Let's build a mutually enriching partnership!

@gabrielivang0810

Hi, there! With over 10 years of experience in Firmware development and expertise in Microcontroller programming, I am well-equipped to take on the task of programming the firmware for your sauna control hardware device. I understand the requirements of the project and am committed to providing a professional and efficient solution as per your job description. Having completed 50+ projects involving Desktop/Mobile applications and Embedded software, I am confident in my ability to handle the complexities of this project effectively. I would love to discuss your project further and explore how we can work together to bring your vision to life. I am eager to connect with you in chat to delve deeper into the specifics of your project. Thanks!

@fakhara1ha

Hey , I just finished reading the job description and I see you are looking for someone experienced in Bluetooth Low Energy (BLE), Firmware and Microcontroller. This is something I can do. Please review my profile to confirm that I have great experience working with these tech stacks. While I have few questions: 1. These are all the requirements? If not, Please share more detailed requirements. 2. Do you currently have anything done for the job or it has to be done from scratch? 3. What is the timeline to get this done? Why Choose Me? 1. I have done more than 250 major projects. 2. I have not received a single bad feedback since the last 5-6 years. 3. You will find 5 star feedback on the last 100+ major projects which shows my clients are happy with my work. Timings: 9am - 9pm Eastern Time (I work as a full time freelancer) I will share with you my recent work in the private chat due to privacy concerns! Please start the chat to discuss it further.