Systems for electronic board connectivity: Wi-Fi and Bluetooth

Connectivity is a fundamental component of the Internet of Things. IoT devices rely on networks to communicate with gateways, applications, servers, routers and other smart devices. Data transmission enables IoT devices to perform the functions for which they were designed. The most̀ used wireless technologies are WiFi and Bluetooth. Both allow several devices to be connected together without the use of wires, enabling information to be transferred and received.

Bluetooth IoT devices

Bluetooth is a wireless technology protocol that relies on physical proximity to manage connections between devices. It uses UHF (ultra-high frequency) radio waves between 2,400 and 2,485 GHz, which can extend up to 50 meters. To be compatible with this data transmission system, an IoT device must have a microprocessor that can drive Bluetooth, as well as a second device to pair with.
There are two commonly implemented versions of the Bluetooth protocol: Bluetooth Classic and Bluetooth Low Energy (BLE), designed for devices that need to consume low amounts of energy.
There are several reasons why developers may choose to use Bluetooth instead of Wi-Fi for IoT devices. Firstly, Bluetooth usually requires physical proximity to initiate a signal transmission, so there is less chance of suffering attacks and remote hacking attempts. Secondly, this system requires much less power than Wi-Fi, so it works better for low-power devices such as basic sensors.

Wi-Fi IoT devices

Wi-Fi is a wireless networking technology that uses various radio wave bands to transmit information between devices. All modern computers and smartphones have this functionality already built in.
To use this on an IoT device, a microchip and firmware are needed to manage the device’s Wi-Fi credentials, as it is more susceptible to cyber-attacks.
Typically, IoT devices using this technology are large fixed hubs, although it can also be provided on smaller devices. To use the system, the smart device needs to be close to a Wi-Fi Internet access point.

Bluetooth IoT and Wi-Fi: comparing features

Speed

Wi-Fi has a much higher maximum speed than Bluetooth: at least 54 Mbps for Wi-Fi, compared to only 3 Mbps for Bluetooth. As a result, Bluetooth is generally used for transferring small blocks of data, such as numerical values from IoT sensors. Wi-Fi, on the other hand, is better for sending large data files, such as videos and photos.

Security

Connectivity is what makes IoT devices so useful, but it can also be a double-edged sword. Connections between devices and with other network entities can create significant vulnerabilities and there is the chance of valuable data being stolen.
Bluetooth’s level of security is sufficient for most purposes, although it cannot be considered a completely inviolable protocol.
If more security is required for the transmission of sensitive data, Wi-Fi offers more guarantees because it uses 256-bit encryption, whereas Bluetooth (Classic and BLE) only uses 128-bit encryption.
Wi-Fi has two popular security accesses: WEP (Wireless Equivalent Privacy) and WPA, WPA2, WPA3 (Wi-Fi Protected Access), making it much more secure.
Isolating IoT devices within one’s network, using virtual private networks (VPNs) and limiting connectivity to their core functions are also additional security measures that can be implemented.

Position and proximity detection

Both Wi-Fi and Bluetooth can provide accurate position and proximity information, although Bluetooth may be a little more reliable in some cases.

Range

Bluetooth generally has a shorter range than Wi-Fi. Class 1 devices have a maximum range of 100 metres, but most Bluetooth devices have a shorter range, often only 10 metres. Furthermore, the range of Bluetooth depends on obstacles and the thickness of the walls between the two devices.
Wi-Fi range, on the other hand, varies depending on several factors such as frequency, transmission power, antenna type and environment. Wi-Fi routers usually have a much longer range than Bluetooth.

Energy consumption

Bluetooth is designed to require less energy than Wi-Fi, particularly with the Bluetooth Low Energy (BLE) protocol.
In IoT devices, Wi-Fi is constantly active to detect and scan available networks, to perform authentication, and to maintain a constant connection during data transmission. Moreover, the more data is exchanged, the greater the energy drain.
Wi-Fi requires 10 times more power than BLE, even to perform the same tasks. Wi-Fi devices require considerable power, about 500µW for ten messages per day, whereas BLE consumes only 50µW.
If Wi-Fi is used, it may be necessary to provide an additional power source because the non-rechargeable battery included in the device may eventually run out and not be able to power the device throughout its lifetime.

Bluetooth and Wi-Fi for IoT: which is the best solution?

The best choice between Bluetooth and Wi-Fi largely depends on the characteristics of the project, the business goals and the application of the device. Syen designs and manufactures IoT devices using the best communication technology for the specific requirements. It provides customized consulting for the development of devices that support the Internet of Things.
It offers comprehensive support at every stage from conception to realisation of the electronic device. Starting from an understanding of the customer’s needs and the required functionality of the device, it elaborates the project, which includes the customized design of the electronic board and the evaluation of the most suitable connectivity technology and power systems for the device.