When embarking on the design of a connected object, several criteria must be taken into account in order to successfully complete your project. Before you begin, you need to have an excellent understanding of market trends, and more importantly, of uses, as the consumer experience is the key to this market.
At Altyor, we have a very good understanding of these issues and have integrated into our teams young engineers who are themselves frequent users of these smart objects. In this article we will look at two key points: the choice of communication technology and the right power source for the object. These two concepts are linked and constitute a starting point for making the right decisions during the design phase.
What are your power autonomy requirements: mains, disposable batteries or rechargeable batteries?
A first essential point is to determine if the product should be autonomous in energy: disposable battery (autonomy in terms of months), rechargeable battery (days) or mains (no limitation). The desired power consumption will partly determine the recommendation of a suitable network.
For example, if the smart object needs to communicate continuously with another object, there is no point in opting for a disposable battery power source. End consumers do not want a product with batteries that have to be changed every week. In this case, rechargeable batteries or even a mains power supply would be the best choice. Moreover, if the object is to be used in a DOMESTIC SETTING, you should go for so-called short-range protocols, whereas OUTDOOR use requires different choices.
Which network should you choose for your smart object? Sigfox, LoRa, Wi-Fi, 3G, 4G, etc.
Z-Wave/EnOcean/Zigbee/Wi-Fi: four networks suitable for the domestic setting
Z-Wave is a communication protocol dedicated to home automation. Wireless and with a range of 30 meters, it is a mesh network, meaning that each device connected to the system is a transmitter of data but can also relay data transmitted by its neighbors, thus extending its range. However, there is one downside: it is best to regularly install devices in its environment that are connected to the mains, to avoid black spots. Battery-powered devices are in sleep mode most of the time so as not to consume too much energy (the Z-Wave protocol uses twice as much energy as Bluetooth Low Energy). Not all devices in the home will necessarily be able to communicate with a smart object via this technology.
EnOcean is a wireless and battery-free communication network. It solves the problem of the lifetime of smart objects. It can capture the energy required for its operation in its environment by means of movement sensors (mechanical energy) and also solar sensors. Moreover, it is often battery operated.
Zigbee (like EnOcean) is known for its low energy consumption and allows more data to flow than Z-Wave. It is also easier to implement for manufacturers of smart objects than Z-Wave or Bluetooth (in its version 4, known as Low Energy, as well as in its version 5, which has just been standardized). However, this network has an average range of only 10 meters.
Bluetooth Low Energy is very widely used worldwide. Almost all smartphones are equipped with this technology, which is commonly used for communication between wearables. It consumes around 20 times less energy than Wi-Fi. In practice, its range is limited to the room where the object is located, whereas Z-Wave passes through walls more easily, owing to its lower frequency. The latest version of this technology, Bluetooth 5, is more suited to IoT; it has twice the range of its older sibling and offers the possibility of making a mesh network to extend its range. This short-range network carries significantly less information than Wi-Fi.
Wi-Fi is very energy intensive and should only be used for mains-powered devices, in the home for example. Universal, it can transfer a large amount of data quickly. This communication protocol can be used to connect surveillance cameras that film large images 24 hours a day.
OUTDOOR use requires different technical choices
2G/3G/4G – Devices connected to these very power-hungry networks are mainly used in mobile mode and therefore usually run on rechargeable batteries with autonomies ranging from a few hours to a few days (cell phone). They are available for domestic use when you are looking for connection security (e.g., 2G in addition to Wi-Fi for an alarm system). The price of subscriptions depends on the amount of monthly data consumed (roaming, data or data + voice). It varies according to the operator chosen and is significantly higher than that of Sigfox and LoRa. In the past, you had to have a space on the smart object to insert a SIM card. Today, SIM cards can be soldered directly to the PCB and therefore take up little space. The main advantage of cellular networks is that they can transfer large amounts of data. As such, it takes 22 seconds in 3G and 1 second in 4G to transmit 83 megabits (according to the operator Virgin Mobile).
With Sigfox devices use very little power to send their data over this network. They are disposable battery operated and can last up to several years! Sigfox has extended its network to many countries in Europe and worldwide, which can facilitate the use of a product at the international level. However, this is still limited because in some countries coverage is very poor. In cities, Sigfox’s range can exceed 10 km, and can reach up to 30 km in the countryside. However, this coverage is still inferior to that of the 2G/3G/4G networks. In return for its low energy consumption, Sigfox can only transport very small amounts of data – between 10 and 100 bps (maximum bits per second). meaning you are limited to 140 messages per day of 12 bytes maximum each. In practice, it is essentially a unidirectional network, although it is possible to downlink on a very limited basis.
LoRa – The very low-power protocol LoRa is used by various companies, such as Bouygues Telecom and Orange. Bidirectional and low cost, it can transmit data at distances of between 2 and 5 kilometers in urban areas and up to 45 kilometers in rural areas. LoRa is more suitable (compared to Sigfox) for applications that require downlink or that require more throughput (at the expense of range). LoRa also allows you to establish a proprietary network without going through an operator. It is ideal for sensors that periodically transmit a small amount of temperature, geolocation, or pressure data, for example. On the other hand, Sigfox is generally cheaper and present in more countries with the same subscription.
NB-IoT/LTE Cat M1: new to the market! The market is constantly evolving and at Altyor we follow this new technology very closely. NB-IoT/LTE Cat M1 is an evolution of 4G. Its main benefit is that it works with the current 4G network and should therefore allow a very fast deployment of the infrastructure, unlike the Sigfox/LoRa networks which require you to create the infrastructure. NB-IoT/LTE Cat M1 allows for low power consumption coupled with long range. This is the missing link, still in the testing phase, but which we believe to be very promising, although the price of the modules to be inserted in the smart object is currently higher than for Sigfox or LoRa.
As you can see, these networks all have their advantages and disadvantages; it is a question of which is most suited to your smart object. Hence, in some situations, companies may be torn between several solutions. It is possible to combine different technologies on the same smart object, although this makes the design of the device more complex.
The mode of communication and power consumption are two entry points in the design of an IOT object, but they are not the only ones. You will also have to include other criteria such as coverage, bidirectionality, instantaneousness, interoperability, the size of the object, and last but by no means least, the cost! This is why, in order to help you design your smart objects, Altyor is committed to really getting to know your needs! Our electronic engineers, with their expertise and experience in this field, will guide you in making the right choices.
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If you have questions or need further information, please contact us at: moc.r1632847314oytla1632847314@ssen1632847314isub1632847314