Alright, so we know that Bluetooth is awesome, and if you don’t, take a read of our Introduction to Bluetooth tutorial. But how exactly do we go about implementing Bluetooth communication in our projects? Well, fortunately for us, there are Bluetooth modules which take care of all the low-level protocol handling and contain what is called a Bluetooth stack. This fancy speak for a board/chip that is programmed to take care of the Bluetooth specific software functions, and provide an easy to use, digital interface for communicating wirelessly, usually via SPI, I2C, or UART. In fact, most Bluetooth modules are designed to provide a wireless TX/RX link between to devices so it’s incredibly easy to get started with them. But there are hundreds of different modules out there, and we provide quite a few different options on our website, so how do you choose one that’s going to be right for your project? Well let’s take a look at some of the most popular modules on our website:
**Note that we’ll be talking about different methods of setup and functionality of different modules which are explained more in depth in our Using Bluetooth Modules tutorial**
Ok, first up is a shield. You knew it had to be here. If you’re working with an Arduino Uno, then chances are you’re using a shield. And what could be more inconvenient that having to run individual wires to a Bluetooth module and ruin the vibe of your construction? Well, no more. This little guy is a shield with plenty of extra headers broken out, and the venerable HC-05 module soldered on. It also provides pin selection headers which allow you to use the hardware UART pins or other pins for software UART. Pretty cool huh? As with most serial Bluetooth modules, you simply use the serial port as normal and the module takes care of the rest. You can use simple AT commands to get device info and configure the module to find out the Bluetooth version that it is operating on. The HC-05 module has a range of around 10m. Note that this shield includes the required 5V-3.3V logic level conversion as the HC-05 operates on 3.3V.
Now we’re stepping up to the big league. This Bluetooth module from Sparkfun is a Class 1 module designed to operate as a TX/RX bridge with a range of 100m! It’s 3V-6V tolerant so you can use it directly with almost every device. It also has RTS/CTS pins designed for use with an RS232-TTL converter as well as straight UART. It’s the crème of the crop as far as Bluetooth classic modules go. There’s also a BlueSMiRF Silver version available which has similar features, but with a shorter range and reduced cost.
And here we find possibly the most well-known Bluetooth module in the DIY sphere. The HC-05 has been the backbone behind thousands of Bluetooth enabled projects because of it’s easy to use TX/RX communication and simple AT commands for extra configuration. The module has been broken out onto an adapter board to provide easy to use, 0.1” pins. The HC-05 module has an onboard 3.3V regulator so you can power it from a 5V board like an Arduino, but you’ll need a logic level converter such as this fantastic bi-directional one from Sparkfun.
This offering is a bit different to the rest, in that it actually has an Arduino compatible microcontroller built-in to the board so you’re completely ready to go. This Bluetooth device is a Bluetooth Low Energy (BLE) module which means it can be run from a coin cell battery (mounted on the back) for power conscious designs. It also has an onboard RGB LED and accelerometer so it’s perfect for all kinds of projects, straight out of the box! The LightBlue Bean is extremely easy to get started with and is a fantastic, low-cost solution for any project.
The Bluefruit module from Adafruit is a great piece of gear because it combines the easy to use nature of TX/RX pipe modules, with the flexibility that Bluetooth LE offers. Thanks to the GATT structure of BLE, you can use simple AT commands to change the way that it handles GATT Services and Characteristics. It features an onboard regulator so you can power it with 5V from your board, and the pins are also 5V tolerant, making it even easier to get started.
This fantastic little board has the same module on board as the previously mentioned Bluefruit LE UART Friend, however, it’s made accessible for wearable projects thanks to the FLORA form factor. It has the same features as the UART Friend, but with large pads suitable for wires and/or conductive thread.
We’ve covered all kinds of different modules that you can integrate directly into your projects via TX/RX communication, however, what about adding Bluetooth functionality to a computer or device with a USB port? Well, fortunately, we’ve got those too. We’ve listed two different options, one that just provides Bluetooth 4.0 support, and one that provides Bluetooth 4.0 AND Wi-Fi in the one handy adapter. It’s perfect for compact computers, or single-board microcomputers which may not have these wireless peripherals integrated into the design.
So there you have it, we’ve taken our favourite Bluetooth modules and dongles and put them head-to-head to help you decide which one is going to be right for your project. Now that you’ve got some info on how to equip your next world-conquering contraption with wireless communication, take a look at our How to Use Bluetooth Modules tutorial for getting started with programming these devices and using them in your projects.