The most common items to look at when choosing a transport are power, distance, and bits. We will go over a few different transport options in this post.
It’s world wide universal, high speed, has no interference, and can go up to 100 meters if you have a long enough cord. The downsides are it’s not portable, has a larger current draw, and the connector is fairly large.
It can move large amounts of data at a high speeds, but it needs a power source. It comes in 2.4 and 5 GHz, but typically only the 2.4 GHz will come on a microcontroller. It has built in security, but it can require authentication on some networks such as at schools and businesses, which some devices may not have the capability to accept the terms and conditions.
There are two options for Bluetooth: Bluetooth Classic and Bluetooth Low Energy (BTLE or BLE) Both run at 2.4 GHz. BLE has lower current draws then Bluetooth Classic. Bluetooth Classic isn’t used in many applications, as BLE is now available. Bluetooth Classic and BLE are not backwards compatible. BLE is the easiest way to make an Apple IOS applications, due to Apple’s requirements. BLE is supported by most phones, tablets, laptops and desk tops. The security is intentionally at a lower level, so depending on your application, you may need to add security. A downside is that it isn’t connected to the internet. To connect to the internet a gateway is needed.
It can be used almost anywhere, but has high power usage. It is available in 2G, 3G and LTE (4G and 5G). 2G, also known as GSM, is only available in some countries, so you will need to verify prior to using. 3G is typically a cheaper option, but is slowly being removed by carriers in some countries, so again you will want to check what country you are using it in and what the expected life time of the service will be. LTE, which is Long Term Evolution, is 4G and 5G. It was developed with IoT in mind and is the typically the best option for new development. With cellular, there are monthly fees. See Digi-Key’s data plans and SIM cards here. Cellular has built in security.
It’s great for world wide, remote locations. The downside is the technology is expensive and high power. You will pay a monthly fee, as well as a per message fee.
It comes in 900 MHz and 2.4 GHz. You will need to set up your own network, and provide a gateway for internet connection. It’s low power, low cost, and can provide mesh networking depending on your application. There is only some security, so you will need to decide if you want to add additional security.
LPWAN stands for Low Power Wide Area Network. Two options for LPWAN are LoRa (Long Range) and Sigfox. While they are similar in style they do have some large differences. For LoRa, you can use any frequency that you can legally use, but you must set up your own network and gateway. Only Semtech can make the chips due to patents. LoRa is free and unlimited messages can be sent. Sigfox has existing networks, which means you don’t have to set up your own, but they are only available in certain cities and it’s slow. Each city has a fix frequency. Only 140 messages can be uploaded and 4 can be downloaded per day.
More information on this topic
If you’d like to learn more in depth on this topic please watch episode one of Digi-Key and Adafruit’s Internet of Things Video series, which is found here: https://www.digikey.com/en/resources/iot-resource-center/videos or visit Adafruits break down on the video https://learn.adafruit.com/alltheiot-transports