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What wireless technology choose to build DIY IoT Project

There are many wireless technologies to create DIY connected objects. If you have complete control of your project. In this article we will take stock best suited to radio wave data transmission technologies for diy projects

WiFi

esp8266 Wemos D1 miniWiFi is the choice most immediate. ESP8266 module especially since the project has become so popular in the Arduino community. The WiFi was not originally designed to develop connected objects. The initial idea was to get rid of ethernet cable to be able to make laptops more fun to use. WiFi is designed to cover a home. If you have a large garden and want to control your gate at 50 meters, you may have difficulties. You may have insufficient coverage and unstable. In this case, you can increase the range of your WiFi network with a repeater. The WiFi will also be ideal for making objects to interact with an online service (publish values on ThingSpeak for example).

Benefits
Disadvantages
  • Relatively high power consumption
  • Limited transmission distance. Use a repeater to extend the WiFi network

Bluetooth

Bluetooth module hc-05Bluetooth is a short-range communication technology. The range of the Bluetooth (version 4.1) module is about 9-10 meters in open field. The version 5 promises 4x more data rate and 2x distance for the same energy consumption.

More reactive than WiFi, Bluetooth is well suited for performing radio controlled car projects, pilot an Arduino project with a smartphone … There are many Android or iOS app to control your projects from your smartphone.

Android

iOS

The HC-05 and HC-06 modules are more common. You can find it for less than € 5. Programming remains quite simple.On can communicate by serial connection or using AT commands. Unlike ESP8266 modules that allow to execute the Arduino code, it will add a Bluetooth module for Arduino which increases the price of the project and its size.

Advantages
  • Responsive controls. Ideal for making remote projects
  • Low consumption
  • Pretty simple programming
Disadvantages
  • Limited range (9 to 10 meters with the version 4.x)
  • Project more expensive (compared to a ESP8266)
  • We must manage pairing

XBee and Zigbee

xbeeThe MaxStream XBee modules is a trademark of the company Digi International. They have been certified by the ZigBee Alliance in 2006 (IEEE 802.15.4). Zigbee is a Bluetooth cousin. While Bluetooth is primarily intended for use in public or a single user can connect to device (ideal for hands-free kit, headphones, remote control …), the Zigbee to create a network ‘objects. Zigbee is not designed to transfert a lot of data (250kbps max.). Zigbee is really reliable and secure. That is why the Zigbee is much used in the industrial world. The main characteristics of XBee/Zigbee are:

  • Frequency: 2.4Ghz
  • Transmission distance in free field
    • XBee 1 and 2: 10 to 100m
    • XBee Pro: up to 1000m
  • Data rate: 250kbps
  • Consumption: 3.3V @ 50mA
  • Inputs / Outputs: x6 10-bit ADC input pins, x8 digital IO pins
  • Security: 128 bit encryption
  • Communication: via the serial port, AT commands and APIs
  • flexible network: supports knots off, easy integration of a new node
  • Maximum number of nodes: 65000
  • Possible network topologies: mesh, point to point, point to multipoint

Zigbee is very well suited for home automation applications. Despite its many strengths, the XBee has not met with the same success as WiFi modules with ESP8266. It must be said that the price of modules rather high (about 23 € and 5.4€ for one Arduino Uno adapter) is a brake for fun DIY projects. For DIY projects the RaspBee card (about 35 € on Amazon) add ZigBee connectivity to a Raspberry Pi.

zibgee ampoule hue philips
Ampoules Hue de Philips : le plus connu des produits utilisant le Zigbee

Other radio : 315MHz, 433Mhz, 868MHz, 2.4Ghz…

WiFi, Bluetooth, XBee are data transmission technologies by radio waves that carry the name of a trademark (a consortium or a company). There are generic radio modules that uses no proprietary communication protocol. There are two main ways to use these modules in your Arduino projects:

  • Manage yourself communication between two devices. In this case, the library VirtualWire is all set for that purpose. Of course there are other libraries (MiRF, Radio …)
  • Use the MySensors library in addition to support the transmission of data created and manages a network connected objects. This solution will be very well suited to develop your own sensors or actuators as part of a DIY home automation project.

Side hardware, there are so many that it is difficult to list them all, we will stay on the best known. If you want to use the library MySensors, the easiest (and cheapest) and opt for a nRF24L01+ (from Nordic Semiconductor). This module is also supported by the gateway RFLink.

Warning. Radio frequencies are subject to regulation (different in each country). You must ensure that you have the right to use the frequency band used by the module. So beware of cheap modules, of uncertain origin, not technical specifications.

Here are some very common modules found on Asian online shopping sites.

315mhz xd-fst XD-RF-5V  : 315MHz

It is one of the most common low-cost modules … but attention to performance (not recommended to make a gateway RFLink for example). There exist several frequencies : 315 MHz (XD-FST) or 433 MHz (XD-RF-5V). The transmission distance is about 200m (free field). Only 20m indoors.

apc220 APC220 : 433MHz

More professional module. With the APC220 module, you can choose the radio frequency from 418 to 455MHz. Supply voltage from 3.4V to 5.5V. Up to 1000m in open field. About 27 €.

nrf24l01 nRF24L01+ : 2.4GHz

It is the most used radio module for MySensors. Now you can use it too for RFLink project. These modules operate at 2.4GHz (same WiFi). There are several versions:

With an external antenna, hopefully reach 1100m in open field at very low speed (check under real conditions).

LoRaWAN or Sigfox (868.1 MHz)

To close this list, here are the two latest communication technology by radio waves that grow very strongly now. They meet every two with the same problem. Propose a long-range wireless digital communication system (several kilometers). In this area, there are two major competitors : LoRaWAN and SigFox. SigFox can be regarded as a telecom operator as it provides a complete solution (protocol and antennas). SigFox is aimed mostly to industry and infrastructures (Smart City).

LoRaWAN : an open project

antenne lorawan 868mhzLorawan (Long Range Wide-area network) was born following the acquisition of Cycleo by Semtech company in 2012. Today, LoRaWAN is supported by the LoRa alliance (Cisco, IBM, Actility, Sagemcom, Eolane, Microchip Technology, Bouygues Telecom, Orange, KPN, Swisscom, SingTel, Proximus …). In France, Orange and Bouygues Telecom are working to deploy their networks and offer new products and associated services. Although LoRaWAN is perfect for DIY projects, as completely open and royalty-free.

Sigfox :

You must pay (every year) to use the Sigfox network. The SigFox network grows very quickly either own name as in France (92% of the population is now covered) or via partnerships (ARQUIVA in England, CELLNEX in Spain …). Sigfox develops local projects to equip large cities (Milan, Dublin, Munich, Seoul, Singapore …). SigFox is present in over 24 countries now.

Many products today rely on SigFox network, here’s a little preview. Generally, subscription fees SigFox network is included for the first month. Prices will depend on the manufacturer (about 20 € per year). You can start your project for approximately 85€.

sigfox smokeo detecteur fumees

Smockeo

A smoke detector connected. 3-month subscription included.

hidnseek sigfox traceur gps

HidnSeek

A GPS tracker to track the position of his car, scooter, bag. The companion app for iOS and Android can locate. You can be notified if the object leaves the surveillance area. 6-month subscription included, after € 19.90.

Flipr sigfox sonde suivi qualité eau piscine

Flipr

A water monitoring probe your pool with its companion application to monitor water quality (chlorine / bromine, pH, alkalinity, hardness, salt, conductivity), temperature and UV index. The access fee to the network is not yet (clearly) detailed.

Summary: What wireless technology to choose for a DIY project?

Rather than giving answers, the best to answer this question and help you choose wireless technology best suited to your project. Here are several criteria that you can consider:

  • Transmission range: Short (remote control), medium (a hundred meters) or long (several hundred meters)
  • Configuration: in a house, outdoor, mixed
    • Wall: thickness, constitution (reinforced concrete does not really help), number
    • flat or embossed
    • Vegetation, fence
    • electromagnetic disturbance: transformer, pumps …
  • Running on battery or AC power
  • Budget
  • Space available
  • Protocol:
    • You manage communication
    • The object will interact with an online service: IFTTT, ThingSpeak …
    • Automation Server: MQTT, MySensors, RFLink, OpenZWave …
  • Your level. If you begin, choose a technology used by a large community of users. You will find many examples and projects.
2nd criteria WiFi Bluetooth XBee Other (433 MHz…) LoRaWan or Sigfox
Transmission range Short

Medium

Long

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Configuration of the land Esay

Medium

Hard

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Protocol Point to point

Cloud

Smart Home

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Community ***** ***** *** **** **

To conclude this article, conventional radio ESP8266 WiFi modules and antennas (433, 868 or 2.4GHz) are the easiest and cheapest solutions to implement for self even develop online projects. If you develop a remote-controlled project, you can turn to the Bluetooth (or XBee).  If this is a project for professional use (industry, logistics, medical, transport …), go directly to the Zigbee in association with LoRaWAN or SigFox.