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Building wireless devices is one of the most interesting task within the Maker community. It feels magical when we can control device wirelessly, in fact most of the IOT applications utilize a wireless protocol in the IOT ecosystem.
So, if you want to make a wireless device, how do you begin ?
The first question would be which frequency I can use ? Well, to answer this query you need to choose one of the unlicensed ISM band as you do not want to select a licensed frequency and seek approvals from the Telecom regulatory and end up paying high fees.
Now that you have selected the frequency band, you need to select which wireless protocol to use ? There are many protocols like Wi Fi, Bluetooth, RFID, NFC, Zigbee, Thread, LoRA etc…
To help you select the wireless protocol, I have made the below table which can provide you a quick reference guide.
Wireless headsets, Speakers, Soundbars etc.
Bluetooth Low energy
Heath monitor, wearables, personal electronics, asset tracking etc.
Zigbee smart energy, Home energy monitors, Embedded sensors etc.
Home automation, electronic locks, Connected home over IP etc.
Laptops, Smartphones, Tablets, etc.
Smart grid, Industrial monitoring, Home automation etc.
Wireless Remote Controls, metering, smoke detectors etc.
Sports and fitness wearables etc.
Drone Remote Control.
Utility meter, Smart parking, IOT sensors, Disaster prediction etc.
3 - 5 feet
Access control, Inventory control, animal tagging, car immobilizer.
< 30 cm
Smart cards, proximity cards, payment.
High read speed - large data
Asset tracking, Container tracking.
860 Mhz - 960 Mhz
High read speed- small data
Pallet tracking or case tracking.
2.4 Ghz - 5.4 Ghz
High read speed-medium data
Container Rail Car, Auto Road Tolls, Pallet tracking.
Which frequency to use ?
The choice of frequency depends upon various factors however one basic approach is to select based on the Telecom regulatory directives which may vary for each country.
The below table shows an example of the unlicensed frequencies under the ISM band :
6.765 - 6.975 MHz
13.553 - 13.567 MHz
26.957 - 27.283 MHz
40.66 - 40.7 MHz
433.05 - 434.79 MHz
Europe, Africa, Russia
902 - 928 MHz
2400 - 2500 MHz
5725 - 5875 MHz
24 - 24.250 GHz
61 - 61.5 GHz
122 - 123 GHz
244 - 246 GHz
RFID : Radio frequency identification (RFID) is used as a reference to a system that uses Radio frequency to transmit the identity of an object or a person in the form of a unique serial number.
NFC : Near field communication (NFC) is a technology that operates at a short range using the 13.56Mhz frequency. The communication between two NFC compatible device can be activated when they are placed in proximity of less than 3 cm.
LoRa : Low power wide area network protocol
IOT : Internet of things
ISM band: Industrial, Scientific and Medical frequency band
6LoWPAN : IPv6 over low power wireless personal area network