Connected products are transforming how organisations monitor equipment, automate processes, collect information and interact with customers. However, developing dependable Internet of Things devices involves much more than connecting a sensor to the internet.
Successful IoT devices depend on the close integration of electronic hardware, embedded software, sensors, communications and data-handling systems. Decisions made during the earliest stages of development can affect power consumption, connectivity, security, reliability, compliance and manufacturing cost throughout the product’s life.
This guide explains the principal elements of Internet of Things devices, the decisions involved in their development and the steps required to turn an initial concept into a reliable, maintainable and production-ready IoT devices.
Use the sections below to explore the IoT product development process or visit our supporting articles for more detailed guidance on embedded systems, microcontrollers, device design and debugging.
Key Points About IoT Product Development
An IoT device is an integrated system combining hardware, firmware, sensors, connectivity and data processing.
The microcontroller, communications technology and power architecture must be selected for the product’s intended use and environment.
Security, compliance and manufacturability should be considered from the beginning rather than added after the prototype has been completed.
Structured prototyping, debugging and validation reduce the risk of unreliable performance and expensive redesigns.
Involving an experienced electronic design partner early can provide continuity from system architecture through to manufacture and lifecycle support.
What Is an IoT or Connected Device?
An IoT device is an electronic product that can collect, process or exchange information through a network. It may communicate with other devices, a local gateway, a cloud platform or a central management system.
Connected devices range from small battery-powered sensors to sophisticated industrial control systems. Their purpose may be to monitor conditions, automate equipment, provide remote control, generate alerts or make data available for analysis.
Although the terms are sometimes used interchangeably, several related technologies have distinct roles.
1. Embedded systems
An embedded system is a combination of electronic hardware and software developed to perform a specific function within a larger product or process. Unlike a general-purpose computer, it is designed around a defined set of tasks.
An embedded system does not necessarily need to be connected to a network. However, embedded systems form the foundation of most IoT devices because they provide the local processing, control and interfaces that the connected product requires.
2. Connected Devices
A connected device can exchange information with another device or system. The connection may use a wired interface, a local wireless network or an internet-based service.
Not every connected device forms part of a large IoT ecosystem. Some products may only communicate with a nearby controller, mobile application or local gateway.
3. IoT Devices
Internet of Things devices normally combine embedded processing with network connectivity. They may collect information from sensors, make local decisions, control equipment and communicate with a wider digital platform.
Examples include:
Environmental monitoring devices
Industrial sensors and controllers
Remote equipment-monitoring systems
Building and energy controls
Medical and laboratory devices
Agricultural monitoring and control systems
Asset-tracking devices
Smart consumer products
4. Sensors and Actuators
Sensors allow a device to measure physical conditions such as temperature, pressure, movement, humidity, position, light or electrical load.
Actuators allow the system to respond by switching equipment, operating a motor, adjusting a valve, activating an alarm or performing another physical action.
The embedded system processes these inputs and determines what action or communication is required.
5. Gateways and Cloud Platforms
Some IoT devices connect directly to the internet. Others communicate through a gateway that collects information from several local devices and passes it to a central system.
A cloud or remote-management platform can then be used to store data, present information, issue commands, manage users or coordinate a fleet of devices.
The Architecture of an IoT Product
An IoT product should be considered as a complete system rather than a collection of separate technologies. Its principal elements will usually include the following.
1. Sensors and Inputs
Sensors provide the information the device needs to monitor its environment or application. The design must consider:
The required accuracy and measurement range
Sampling frequency
Response time
Calibration
Environmental conditions
Component cost and availability
Power consumption
The interface between the sensor and the processor
Poor sensor selection can limit the performance of the whole product, even when the remaining electronics and software operate correctly.
2. Microcontroller or Processor
The microcontroller acts as the control centre of many embedded and IoT devices. It reads inputs, performs calculations, controls outputs and manages communications.
Selection should be based on the application rather than processing power alone. Important considerations include:
Processing performance
Memory capacity
Available communications interfaces
Number and type of inputs and outputs
Real-time requirements
Power-saving modes
Security features
Operating temperature
Unit cost
Long-term availability
Development tools and software support
3. Embedded Firmware
Firmware provides the instructions that control the device. It may manage sensor readings, communications, user interfaces, data storage, diagnostics and control functions.
A structured firmware architecture helps make the product:
Easier to test
Easier to maintain
More adaptable
More secure
Easier to update
Less vulnerable to unexpected interactions between functions
Firmware should be developed alongside the hardware rather than treated as a separate task at the end of PCB development.
4. Connectivity
Connectivity allows the device to exchange information with another device, network or digital platform. The best option depends on the required distance, data rate, environment, power availability and infrastructure.
Possible technologies include:
Wi-Fi
Bluetooth and Bluetooth Low Energy
Cellular communications
Ethernet
Long-range, low-power wireless systems
Industrial communications protocols
Wired serial communications
Proprietary local networks
most familiar communications technology is not always the most appropriate. A connection that works well during a bench demonstration may perform differently inside an enclosure, within a building or across a large industrial site.
5. Local and Remote Data Processing
Some devices transmit raw information to another system for processing. Others process information locally and send only a result, alert or summary.
Local or edge processing can:
Reduce the amount of data transmitted
Improve response time
Maintain operation when connectivity is interrupted
Reduce dependence on cloud services
Improve control over sensitive information
The balance between local and remote processing should be defined during system architecture.
6. User Interface
The user interface may consist of physical controls, a local display, a web portal, a mobile application or an interface within a larger management system.
The design should reflect how the product will be installed, operated, maintained and updated. An interface suitable for an engineer during development may not be appropriate for the product’s eventual users.
7. Power Supply and Power Management
Power requirements affect product size, operating life, reliability and cost.
A mains-powered industrial controller has very different requirements from a battery-powered remote sensor. For low-power products, the design must consider:
Active and sleep-mode current
Sensor operating cycles
Communications frequency
Data-transmission duration
Battery capacity
Power conversion efficiency
Wake-up events
Temperature effects
Battery replacement or recharging
Power management should be considered throughout the hardware and firmware design.
8. Security and Device Identity
Security must be built into the architecture of a connected device. Depending on the application, this may include:
Unique device identities
Secure storage of credentials
Authentication
Encryption
Access control
Secure boot
Signed firmware
Protected update processes
Diagnostic logging
Recovery from interrupted or unsuccessful updates
Security measures should be proportionate to the risks presented by the product, its data and the systems to which it connects.
The IoT Product Development Process
A structured development process helps prevent individual design decisions from creating problems elsewhere in the product.
1. Define the Requirements and Use Case
The project should begin with a clear description of what the product must do, where it will operate and how it will be used. Requirements may include:
The measurements or functions required
The intended users
Installation conditions
Operating environment
Communications range
Expected battery life
Response times
Data requirements
Product size
Target manufacturing cost
Anticipated production volume
Applicable standards and regulations
Expected product life
Maintenance and update arrangements
A detailed specification reduces ambiguity and provides an objective basis for testing the finished product.
2. Develop the System Architecture
The system architecture defines how hardware, firmware, communications and external services will work together.
At this stage, the development team should decide:
Which functions will be performed locally
Which information will be transmitted
How the device will respond if communications fail
How devices will be identified and managed
Whether remote updates are required
How faults will be detected and recorded
How the product will interface with other equipment
How the design could be scaled or adapted
Early architecture decisions often have a greater effect on long-term product performance than the selection of individual components.
3. Select Sensors and Components
Sensors, processors, communications devices, memory and power components should be selected as part of the same system.
Selection should account for performance, cost and availability, but also for:
Environmental ratings
Lifecycle status
Supply-chain risk
Alternative sources
Software support
Compliance documentation
PCB space
Manufacturing requirements
Selecting a component solely because it is convenient for an early prototype can create problems when the product moves towards manufacture.
4. Select the Connectivity Technology
The communications method must suit the application’s real operating conditions.
Factors to consider include:
Required range
Data volume
Transmission frequency
Latency
Power consumption
Network availability
Subscription or infrastructure costs
Interference
Physical obstructions
Security
Regulatory requirements
Compatibility with existing systems
Connectivity should be tested in a representative environment rather than assessed only on a development bench.
5. Design the Electronic Hardware and PCB
The electronic design brings together the processor, power supply, sensors, communications components and external interfaces.
The PCB design must address:
Signal integrity
Power distribution
EMC performance
Thermal management
Component placement
Antenna location
Mechanical constraints
Test access
Manufacturing tolerances
Assembly processes
PCB design decisions can significantly affect communications range, sensor accuracy, reliability and regulatory testing.
For related guidance, visit our Electronic Design Services knowledge hub or learn more about Circad’s PCB design services.
6. Develop the Embedded Firmware
Firmware development should proceed alongside hardware development so that assumptions can be tested early.
The firmware may need to manage:
Sensor acquisition
Device control
Communications
Data validation
Error handling
Power-saving modes
Local storage
User interaction
Security
Diagnostics
Firmware updates
Modular firmware can make future modifications and product variants easier to manage. It also helps isolate faults and supports more efficient testing.
7. Build and Evaluate Prototypes
A prototype provides an opportunity to test technical assumptions before the design is committed to production.
Different prototypes may be appropriate at different stages:
A proof of concept to test a particular technology
A development prototype to integrate hardware and software
A pre-production prototype representative of the finished product
A pilot build to confirm assembly and test processes
A development board may be useful during initial investigation, but it is rarely an ideal final product platform. Custom hardware may be needed to achieve the required size, cost, power consumption, reliability and compliance performance.
8. Debug the Integrated System
Embedded-system faults can result from hardware, firmware or the interaction between the two. Symptoms may also be intermittent or dependent on timing, temperature, communications activity or power conditions.
Effective debugging may involve:
In-circuit debuggers
Oscilloscopes
Logic analysers
Protocol analysers
Network tools
Diagnostic firmware
Current measurement
Event logging
Controlled fault injection
Repeated and automated tests
A design that includes accessible test points, diagnostic functions and meaningful error reporting will normally be easier to develop and support.
9. Validate Performance and Reliability
Validation confirms that the product meets its defined requirements.
Testing may include:
Functional testing
Communications testing
Range and signal-strength testing
Power-consumption measurement
Battery-life evaluation
Environmental testing
Stress and endurance testing
Recovery after power or network interruption
Firmware-update testing
Security testing
User and installation testing
Testing should include expected operation and credible failure conditions. A connected product must be able to respond predictably when a sensor fails, communications are unavailable or power is interrupted.
10. Prepare for Compliance
Compliance requirements should be identified before the design is completed.
Depending on the product and intended market, relevant considerations may include:
Electromagnetic compatibility
Electrical safety
Radio equipment requirements
Restriction of hazardous substances
Environmental obligations
Product-specific standards
Cybersecurity requirements
CE or UKCA conformity procedures
Designing with compliance in mind can reduce the likelihood of failed tests, major redesigns and delays to market.
11. Design for Manufacture and Test
A technically functioning prototype is not necessarily ready for efficient manufacture.
Before production, the design should be reviewed for:
Component availability
PCB fabrication
Automated assembly
Programming
Inspection
Functional testing
Traceability
Mechanical assembly
Rework
Production documentation
Design for manufacture and design for test help reduce assembly problems and make it easier to confirm that every completed unit operates correctly.
Learn more through our PCB Assembly and Manufacturing knowledge hub and Electronic Manufacturing Services guide.
12. Plan for Production and Lifecycle Support
Product development does not end when the first batch is delivered.
Connected devices may require ongoing management of:
Firmware versions
Security updates
Component obsolescence
Manufacturing changes
Field faults
Calibration
Technical documentation
Product variants
Cloud or communications services
End-of-life arrangements
Planning for long-term support during development can make the product easier and more economical to maintain.
Key Decisions in IoT Device Design
1. Choosing the Right Connectivity
Connectivity should be chosen by examining the complete application rather than selecting a technology in isolation.
For example, Wi-Fi may offer high data capacity where network infrastructure is readily available, while Bluetooth Low Energy may be better suited to short-range, low-power communication. Cellular systems can support remote deployment but may introduce ongoing service costs. Wired communications may provide greater reliability in fixed industrial environments.
The decision should balance:
Range
Data rate
Power
Infrastructure
Cost
Security
Reliability
Scalability
2. Managing Power Consumption
Low-power operation depends on both hardware and firmware.
Power consumption can be reduced by:
Selecting efficient components
Using appropriate processor sleep modes
Limiting sensor operating time
Reducing unnecessary transmissions
Processing data locally
Optimising voltage conversion
Choosing communications technology suited to the use case
Battery-life estimates should be confirmed through measurement under representative operating conditions.
3. Integrating Sensors
Sensor performance can be affected by PCB layout, mechanical design, temperature, electrical noise and calibration.
The sensor must therefore be considered within the complete product rather than treated as an isolated component.
Important questions include:
Is the sensor correctly positioned?
Could heat from other components affect it?
Is it vulnerable to electrical noise?
Does it require calibration?
How will drift or failure be detected?
Can it be replaced or serviced?
4. Balancing Processing Power and Cost
A more powerful processor is not automatically a better choice.
Excess capability can increase component cost, power consumption and software complexity. Insufficient capacity may restrict future development or produce unreliable performance.
The selected device should provide adequate processing, memory, interfaces and security while retaining an appropriate margin for future updates.
5. Developing Maintainable Firmware
Firmware should be designed to accommodate testing, updates and future development.
Maintainability can be improved through:
Modular software structure
Defined interfaces
Version control
Coding standards
Automated testing
Clear documentation
Diagnostic logging
Controlled release processes
These practices are particularly important when a device will remain in service for many years.
6. Designing for Cybersecurity
A connected device creates a possible route into other systems and may handle commercially or personally sensitive information.
Security planning should consider:
Who can connect to the device
How users and devices are authenticated
How credentials are stored
How data is protected
How firmware is updated
What happens when vulnerabilities are identified
How access can be withdrawn
How long security support will be provided
Cybersecurity should be treated as a lifecycle responsibility rather than a one-off feature.
7. Designing for the Operating Environment
A device that operates successfully in an office or laboratory may behave differently in a factory, vehicle, farm or outdoor installation.
Environmental design considerations may include:
Temperature
Humidity
Dust
Water
Vibration
Shock
Electrical interference
Power quality
Chemical exposure
User handling
The enclosure, PCB, connectors and firmware must all reflect the conditions in which the product will operate.
8. Planning for Scalability
A system designed for ten prototype units may not be suitable for thousands of deployed devices.
Scalability affects:
• Device identification
• Data volumes
• Network capacity
• Firmware deployment
• User management
• Monitoring
• Technical support
• Production test
• Traceability
• Component sourcing
These requirements should be considered before the product architecture becomes difficult to change.
Common IoT Product Development Risks
1. Treating the Prototype as the Finished Product
A proof of concept demonstrates that an idea is technically possible. It does not necessarily demonstrate that the product is reliable, compliant or economical to manufacture.
Moving directly from a development platform to production can leave unresolved problems involving power, mechanical design, testability, component availability and certification.
2. Selecting Technology Before Defining the Requirements
Starting with a preferred microcontroller, wireless module or cloud platform can constrain the product unnecessarily.
Requirements should determine the technology, rather than the technology determining what the finished product can achieve.
3. Underestimating Power Requirements
Battery-life calculations can be misleading when they omit transmission peaks, sensor warm-up periods, voltage-conversion losses or changes in battery performance.
Measurements should be taken across realistic operating cycles and environmental conditions.
4. Testing Connectivity Only in Ideal Conditions
Wireless performance can be affected by walls, machinery, enclosures, interference, antenna placement and the orientation of the finished device.
Connectivity should be tested where and how the product will actually be used.
5. Adding Security Late in Development
Security features added after the architecture has been defined may be difficult to implement effectively.
Late changes can affect processing requirements, memory, communications, update mechanisms and manufacturing procedures.
6. Failing to Plan for Updates
A connected device may need firmware changes to correct faults, add functionality, maintain compatibility or address security issues.
The method for updating, validating and recovering the device should be defined before deployment.
7. Ignoring Compliance Until the Prototype Is Complete
Compliance problems can require changes to PCB layout, filtering, power architecture, firmware, communications components or the enclosure.
Identifying the applicable requirements early helps reduce the risk of expensive redesign.
8. Designing Without Manufacture and Testing in Mind
A prototype assembled by an engineer may depend on manual adjustments or specialist knowledge that cannot be reproduced efficiently in production.
Manufacturing and testing requirements should influence component selection, PCB layout, programming interfaces and diagnostic features.
When Should You Involve an IoT Design Partner?
An experienced design partner can be valuable when a project requires several technical disciplines to work together.
You should consider involving an IoT or embedded-system design partner when:
You have a product idea but no complete technical specification - A design partner can help convert the commercial idea into defined functional, technical and manufacturing requirements.
Hardware, firmware and connectivity must be developed together - Connected products depend on interaction between several systems. Separating responsibility for each element can create gaps, assumptions and integration problems.
You need to turn a development-board prototype into a commercial product - A custom design may be required to achieve the necessary size, cost, power consumption, reliability and manufacturability.
An existing product is unreliable - Intermittent faults may arise from hardware, firmware, timing, power or communications. A structured review can help identify the underlying cause rather than repeatedly treating individual symptoms.
Your internal team lacks a particular discipline - A project may require specialist experience in PCB design, embedded software, wireless communications, compliance or production engineering that is not available internally.
Compliance requirements are unclear - Early guidance can help identify relevant standards, testing requirements and documentation before the design becomes expensive to change.
The product must remain available for many years - Long-term products require appropriate component selection, documentation, update planning and obsolescence management.
You need continuity from design to manufacture - Using a partner that understands both electronic development and production can reduce the risk of a prototype that is difficult or expensive to manufacture.
IoT and Embedded Systems Guidance
Explore the following articles in order to build your understanding from embedded-system fundamentals through to IoT product design and validation.
1. The Advantages of Embedded Systems in Design and Efficiency
Embedded systems enable electronic products to perform defined tasks efficiently, responsively and reliably.
This introductory guide examines the benefits of embedded systems, including compact design, low power consumption, real-time control, customisation and scalability.
2. An Introduction to Microcontrollers
Microcontrollers provide the processing and control functions at the centre of many embedded and connected products.
This article explains the role of the MCU, the difference between microcontrollers and microprocessors and the factors involved in selecting a device for an application.
3. Designing High-Quality IoT Devices
The quality of a connected product depends on decisions concerning communications, hardware, firmware, power management, data handling, security and maintainability.
This guide explores the engineering considerations that help produce a dependable and production-ready IoT device.
4. Embedded System Debugging: Best Tools and Techniques
Embedded faults may be caused by hardware, firmware or interactions between the two.
This article explains the tools and techniques used to investigate timing, communications, memory, power and system-integration problems before they become expensive failures in production or in the field.
How Circad Supports IoT and Connected Product Development
Circad helps organisations develop electronic products that combine embedded processing, sensors, communications and intelligent control.
Our capabilities can support individual stages of a project or provide continuity from the initial specification through to production.
Support can include:
Requirements definition
System architecture
Electronic circuit design
PCB design and layout
Microcontroller and component selection
Embedded firmware development
Sensor and actuator integration
Communications integration
Power-management design
Prototype development
Hardware and firmware debugging
Compliance preparation
Design for manufacture and test
PCB assembly
Production testing
Product redesign and lifecycle support
By considering design, compliance and manufacturing requirements together, we help clients reduce development risk and create products that are better prepared for reliable production.
Frequently Asked Questions
What is the difference between an embedded system and an IoT device?
An embedded system is an electronic hardware and software system designed to perform a defined function. An IoT device is normally an embedded system that can also communicate with another device, network, gateway or internet-based platform.
Not every embedded system is connected, but most IoT products depend on embedded technology for processing, control and communication.
What components are required in an IoT device?
An IoT device will normally include a microcontroller or processor, embedded firmware, a power supply and a communications interface.
Depending on its function, it may also require sensors, actuators, memory, a user interface, local data storage, security components and connections to a gateway or cloud platform.
How do you choose a microcontroller for an IoT product?
Microcontroller selection should be based on the product’s processing, memory, connectivity, input and output, security, power and environmental requirements.
Cost, component availability, development support and future expansion should also be considered. The most powerful device is not always the most appropriate or economical choice.
Which wireless technology should an IoT device use?
The correct technology depends on the required range, data rate, power consumption, network infrastructure, operating environment and cost.
Wi-Fi, Bluetooth Low Energy, cellular and long-range low-power systems each suit different applications. The choice should follow a review of the complete use case rather than familiarity with a particular technology.
How can power consumption be reduced in an IoT device?
Power can be reduced through efficient component selection, processor sleep modes, optimised sensor sampling, shorter communications periods and appropriate power-conversion design.
Firmware has a significant influence because it determines how often components operate, process information and transmit data.
How are IoT devices tested?
Testing may include functional performance, communications, power consumption, environmental behaviour, security, firmware updates and recovery from interruptions.
The product should be tested under representative operating conditions and against the requirements defined at the start of the project.
What compliance requirements apply to connected devices?
The requirements depend on the product, communications technology, application and markets in which it will be sold.
Possible considerations include electromagnetic compatibility, radio equipment, electrical safety, environmental legislation, cybersecurity and product-specific standards. These should be identified early in development.
Can a development-board prototype be used as the finished product?
Development boards are useful for exploring technologies and proving initial concepts. However, they may not provide the required size, cost, power consumption, environmental performance, security or manufacturing efficiency for a commercial product.
A custom PCB is often required before production.
Can Circad redesign an existing connected product?
Yes. An existing product may be reviewed to address reliability, component obsolescence, manufacturing cost, connectivity, firmware, compliance or production issues.
The appropriate approach will depend on the available design files, source code, documentation and examples of the existing hardware.
Can Circad support both design and manufacture?
Circad can support electronic and PCB design, embedded development, prototyping, compliance preparation, PCB assembly, testing and ongoing manufacturing.
Involving manufacturing expertise during design can help ensure the product is suitable for efficient assembly, programming, inspection and functional testing.
Develop a Reliable, Production-Ready Connected Product
Whether you are investigating an initial concept, refining a prototype or resolving problems within an existing product, early engineering decisions will determine the reliability and commercial viability of the finished device.
Circad can help you bring together hardware, firmware, connectivity, compliance and manufacturing within a structured product-development process.
EMBEDDED SYSTEM DEBUGGING
IoT DEVICES
EMBEDDED SYSTEM ADVANTAGES
