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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.
FreQuency | Distance | Data Rate | Protocol | Applications |
|---|---|---|---|---|
2.4Ghz | 100m | 3Mbps | Bluetooth Classic | Wireless headsets, Speakers, Soundbars etc. |
2.4Ghz | 200m-400m | 2Mbps | Bluetooth Low energy | Heath monitor, wearables, personal electronics, asset tracking etc. |
2.4Ghz | 10m-100m | 250Kbps | Zigbee | Zigbee smart energy, Home energy monitors, Embedded sensors etc. |
2.4Ghz | 20m-30m | 250Kbps | Thread | Home automation, electronic locks, Connected home over IP etc. |
2.4Ghz/5Ghz | 200m | 72Mbps | WiFi | Laptops, Smartphones, Tablets, etc. |
2.4Ghz | 100m | 250kbps | LoWPAN | Smart grid, Industrial monitoring, Home automation etc. |
Sub 1Ghz | 1600m | 500Kbps | Proprietary | Wireless Remote Controls, metering, smoke detectors etc. |
2.4Ghz | 30m | 60kbps | ANT/ANT+ | Sports and fitness wearables etc. |
2.4Ghz | 1600m | 2Mbps | Proprietary | Drone Remote Control. |
Sub 1Ghz | 10Km | 27Kbps | LoRa | Utility meter, Smart parking, IOT sensors, Disaster prediction etc. |
125 Khz | 3 - 5 feet | 8 kbps | RFID | Access control, Inventory control, animal tagging, car immobilizer. |
13.56 Mhz | < 30 cm | 848 kbps | RFID,NFC | Smart cards, proximity cards, payment. |
433 Mhz | 300m | High read speed - large data | RFID | Asset tracking, Container tracking. |
860 Mhz - 960 Mhz | 10m | High read speed- small data | RFID | Pallet tracking or case tracking. |
2.4 Ghz - 5.4 Ghz | 100m | High read speed-medium data | RFID | 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 :
Frequency Range | Bandwidth | Center frequency | region |
|---|---|---|---|
6.765 - 6.975 MHz | 0.03 MHz | 6.78 MHz | Local |
13.553 - 13.567 MHz | 0.014 MHz | 13.56 MHz | Global |
26.957 - 27.283 MHz | 0.326 MHz | 27.18 MHz | Global |
40.66 - 40.7 MHz | 0.04 MHz | 40.68 MHz | Global |
433.05 - 434.79 MHz | 1.74 MHz | 433.92 MHz | Europe, Africa, Russia |
902 - 928 MHz | 26 MHz | 915 MHz | Americas |
2400 - 2500 MHz | 100 MHz | 2450 MHz | Global |
5725 - 5875 MHz | 150 MHz | 5800 MHz | Global |
24 - 24.250 GHz | 250 MHz | 24.125 GHz | Global |
61 - 61.5 GHz | 500 MHz | 61.250 GHz | Local |
122 - 123 GHz | 1000 MHz | 122.5 GHz | Local |
244 - 246 GHz | 2000 MHz | 245 GHz | Local |
Terminology
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
