Have an idea you’d like to bring to market? In this series, John Teel walks through the process of scaling up from prototype to production. Follow each installment for a closer look at how to incorporate individual components.
Does your new project require short-range wireless communication capabilities? If so, there are several wireless technologies available to choose from when developing your new product. Each technology has advantages and disadvantages and the best choice depends on the application.
In this article we’re going to compare the four most popular wireless technology standards for new electronic products, including: Bluetooth Classic, Bluetooth Low-Energy (also called Bluetooth Smart), WiFi, and WiFi Direct.
Data Transfer Speed
If fast data throughput is the most important specification for your product then most likely WiFi or WiFi Direct will be the best choice. Everyone knows of WiFi but most haven’t heard of WiFi Direct, although that is slowly changing.
An access point is required for standard WiFi (typically a router). So to transfer information from one device to another the data must pass through the access point.
WiFi Direct is as fast as standard WiFi, but it eliminates the need for an access point. WiFi Direct allows direct device-to-device communication just like with Bluetooth.
|Wireless Standard||Transfer Speed|
|Bluetooth Low-Energy||1 Mbps|
|Bluetooth Classic||2-3 Mbps|
|WiFi / WiFi Direct||100-250 Mbps|
Table 1 – Transfer Speed Comparison
WiFi and WiFi Direct have a maximum data throughput about 10x faster than what is obtainable with Bluetooth Classic. For example, if your application requires video streaming you’ll need a very high speed wireless connection. Neither Bluetooth technology will be fast enough (except for perhaps very low definition video), so you’ll want to provide WiFi / WiFi Direct capabilities.
At the other end of the speed range is Bluetooth Low-Energy which is about half as fast as Bluetooth Classic. BLE is usually appropriate for transferring small amounts of intermittent data, such as temperature, humidity, motion data, GPS coordinates, etc.
Normally, if your application requires the constant transmission of data, such as when streaming audio, then Bluetooth Classic is the best choice. Bluetooth Classic is especially optimized for streaming data, versus BLE which is optimized for infrequent bursts of rather simple data.
That being said, it’s possible to stream audio using BLE, just not with the audio quality of Bluetooth Classic. However, it requires custom BLE firmware. Bluetooth firmware provider Searan offers a custom Bluetooth LE stack that allows audio streaming. This may be a good solution if battery life is more important for your product than having the highest fidelity audio.
WiFi and WiFi Direct have a maximum transmission range of around 200 feet (60 meters). Bluetooth (Classic or BLE) normally has a maximum range of only about 60 feet (20 meters).
The larger range of WiFi is possible because of its higher transmission power. The trade off for this increased range is battery life. WiFi will drain the battery much faster than Bluetooth, especially Bluetooth Low-Energy.
|Wireless Standard||Transfer Speed|
|Bluetooth Low-Energy||50 ft typically, up to 1,500 ft using range extender|
|Bluetooth Classic||50 ft typically, up to 3,000 ft using range extender|
|WiFi / WiFi Direct||200 ft typically|
Table 2 – Operating Range Comparison
There are really different classes of Bluetooth transmitters. The majority of Bluetooth products use a class 2 transmitter with a operating range around 50 feet. But it’s possible to also use a class 1 transmitter which has a range closer to 300 feet (100 meters). However, just as with WiFi Direct, the higher power output reduces battery life.
It’s actually possible to extend the range of Bluetooth even further by adding a range extender circuit which primarily increases the receiver’s sensitivity. For example, Silicon Labs offers a long-range Bluetooth LE module called the BLE112LR that has a maximum range approaching 1,500 feet (450 meters). They also offer a long-range Bluetooth Classic module that has an even larger range of over a half a mile (1 km). Keep in mind all of these range distances assume line-of-sight.
Power Usage vs. Battery Life / Size
A larger transmission range and faster data transfer speeds mean increased power usage which equals shorter battery life. If battery life or battery size are key features for your product then power usage will be extremely important.
Easily the best wireless technology for ultra-low power applications is Bluetooth Low-Energy (BLE). BLE was developed primarily for Internet of Things (Io) applications that commonly run from a single watch battery.
A well designed BLE device can run for years on a small watch battery because most BLE products are designed to transmit data only occasionally.
For example, a device may be programmed to only transmit data for 1 second every minute. So the device is only transmitting for 1/60 = 1.7% of the time, and the remaining 98.3% of the time the device is in ultra low-power sleep mode.
Smart Phone Compatibility
If compatibility with older smart phones is critical for your product, then Bluetooth Classic or standard WiFi may be the best choice. All smart phones support Bluetooth Classic and WiFi, but only newer phones support Bluetooth Low-Energy and WiFi Direct.
|Wireless Standard||Google Android||Apple iOS|
|Bluetooth Classic||All versions||All versions|
|Bluetooth Low-Energy||Version 4.3+||Version 4S+|
|WiFi||All versions||All versions|
|WiFi Direct||Version 4.0+||Version 5S+|
Table 3 – Smart Phone Compatibility Comparison
All four wireless technologies provide a high level of security. However, WiFi and WiFi Direct use 256-bit encryption whereas Bluetooth (both Classic and LE) use only 128-bit encryption.
For the majority of applications Bluetooth provides sufficient security protection. But if security is a really high priority for your product then WiFi or WiFi Direct is a better choice.
Development Cost and Complexity
There are two hardware functions required for wireless functionality: a RF transceiver (a transceiver is a transmitter and a receiver), and a microcontroller or microprocessor executing the wireless protocol firmware (also called a stack).
Your life will be much simpler if you use a System-On-a-Chip (SoC) solution that integrates both the transceiver and microcontroller into a single chip.
Using a single chip SoC solution will drastically reduce your development cost by minimizing the likelihood of problems, and by including the wireless protocol stack already built-in. Otherwise you need to purchase the stack separately which isn’t cheap. Expect to pay a minimum of $10k plus a per unit licensing fee.
Bluetooth Low-Energy is the easiest and cheapest type of wireless functionality to implement in a new product, and all BLE chip offerings are single-chip SoC solutions.
Numerous chip makers offer BLE SoC solutions, including Cypress, CSR, Nordic, Dialog, and Texas Instruments. BLE chips can be purchased for only $1 to $2 in volumes of a few thousand.
In most cases, it’s best to start off using a module for any wireless functions so as to reduce the cost of FCC certification and to reduce your development risk.
Manufacturing Unit Cost
The other critical cost is the production cost per unit which determines your profit margin. For your early units that use wireless modules the unit cost will be quite high. So you may have to sell your early units at no profit.
When creating a new product your top priority should be minimizing the development costs (and risk), not minimizing the manufacturing unit cost. Instead, focus on reducing the production cost once you have customers and are ready for mass manufacturing.
As is always the case with new product design there are trade-offs between the various wireless technologies. No technology is best for every application. You need to prioritize the specifications that are most critical for your product. Selecting the wireless technology for your product can be easy or complex. If data transfer speed is the most important specification for your product then your decision is rather easy: WiFi or WiFi Direct. If battery life or battery size are your most critical criteria then your decision is also rather easy: Bluetooth Low-Energy. If keeping your development and production costs low is your top priority then Bluetooth LE is again your best option.
But if transfer speed, battery life, and cost are all equally important then your decision is more complicated. Welcome to the world of new product development!
Do you want to learn more about developing a new electronic product? Then be sure to check out The Ultimate Guide – How to Develop a New Electronic Product.