Getting the right hardware for you

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Connecting the RFu-328 to your project

The RFu-328 can be surface mounted or connected to two 10 pin connectors, which gives the the RFu-328 an XBEE footprint. If you are just starting out then the developer board is a very good starting place. You can surface mount the RFu-328 to the board or use the supplied 10 pins connectors which will allow you to attach and remove the RFu-328 from the board quite easily. The surface mount is obviously quite permanent as RFu-328 is soldered directly to the development board making it hard to separate in the future. 

The developer board has a great layout with each access to the RFu-328 pins, a prototyping area where you can solder in your electronic parts, an FTDI connector for programming the RFu-328, space for battery clips and an area to connect power pods which convert the battery power into a regulated constant voltage required by your project. 

Surface Mounted

 10 Pin Connectors



Another more compact alternate to the developer board is to use the wireless sensor case kit that is a very small PCB powered by a coin cell battery and housed in a match box sized enclosure. Surface mounting is not an option as the RFu-328 would get in the way of the battery. You will need to use the supplied 10 pin connectors. This is a good option for you to deploy your RFu-328 after you have used the developer board to upload your code and test that everything is working. This kit does not have the FTDI interface, but does have some pads where you can connect some sensors (switch, temperature, light sensors and LED's). 


Communicating with other RF modules

Your RF project will obviously want to communicate with other RF modules either connected to a mini computer like the Raspberry Pi, or a PC, or other RF modules (like the RFu-328). If it's the latter then you will need two or more RFu-328's and developer boards. If you want to communicate between an RFu-328 and a Raspberry Pi then a wireless base station receiver/transmitter module connected to the Raspberry Pi using a Slice Of Pi shield is the best way to go. Links to these components are at the top of the page.


Power options

There are many different options for powering the RFu-328. It needs a between 3.3V and 3.6V. An external power supply is always a good option because you don't need to worry about saving power (unless you are tracking your carbon footprint!).

Raspberry Pi Power
I use a Raspberry Pi for many of my projects so the 3.3V power supply from the Raspberry Pi is a good option for powering the RFu-328. 

USB Power
If you are using the FTDI cable (explained below) it will supply 3.3V power to the developer board through the FTDI connector. This is a good option while testing your Arduino sketches.

Battery Power 
If you choose to use battery power there are no standard batteries that supply 3.3-3.6V. You will need to either step up and step down the voltage. A power pod will either increase the voltage or decrease it and provide a regulated voltage. 

PowerPOD 1117 3V3


This PowerPOD is capable of taking a 4.4v to 16V input to give a 3.3V regulated output. It's often used to power 3.3V devices from 4 AA batteries or a 9V battery. At 12V and above keep current consumption down to minimise heat.

PowerPOD NCP1402 3V3


This PowerPOD is capable of taking a 1v to 3v input to give a 3.3v "stepped up" regulated output. It's often used to power 3.3V devices from 1 or 2 AA batteries. If you have a project with lower power requirements (e.g. a temperature sensor) then you can use this power pod to step up the 1.5V from a single AA battery. I use this on many of my projects because the developer board has clips for a single AA or AAA battery.


The power pods work as follows (batteries will differ depending on which power pod you use):




Hardware for programming the RFu-328

The RFu-328 is programmed using the Arduino Integrated Development Environment (IDE). This is supported by most operating systems (Linux, Windows, Mac etc..). Instructions on how to install the IDE is covered later. 

Once you have finished writing your code and you are ready to upload it to the RFu-328 you have two choices on how to connect the RFu-328 with the Arduino IDE:

1. Use an FTDI Cable

The FTDI Cable (shown in the figure below) is Mini USB cable connected to a 6 pin 3.3V FTDI Serial Adapter. The USB cable connects on one end to your computer where the Arduino IDE is running using the USB port and on the other end to the developer board using the FTDI connector (show in the second picture below).


Mini USB Cable attached to a 3.3V FTDI board


FTDI Cable attached to the FTDI connector on the developer board

FTDI Drivers
Your operating system may not automatically detect the FTDI cable which means you will need to install an FTDI driver for your operating system. I am using Windows 7 and it did detect my FTDI cable, but I have read that sometimes it is not detected. You can download and install FTDI drivers from this link:


2. Use over the air programming (OTAMP)

The RFu-328 can remarkably be programmed over the air. You can use OTAMP to transmit the code that you write over the airwaves to the RF module on the RFu-328. Over the air programming is covered later on, but in order to use it you need to have your development environment (your PC or Raspberry Pi) connected to an RF module that can transmit. The Raspberry Pi with a Slice of Pi shield and and a Wireless Base Station Receiver module will work well. Alternately you can use an RF USB dongle for a PC (not covered in this tutorial at this time). 

OTAMP does come with some complications that need to be considered. Firstly, in order to program and RFU-328 over the air the wireless module on the RFu-328 needs to be powered on and ready for upload. In most of my projects I have found that I use the power saving features of the RFu-328 (covered later) which switch off the radio and only switch it on when needed. So OTAMP is not ideal in this case because you will first need to "wake-up" the RFu-328 from its sleep before doing the upload. Another hindrance is the state of the radio. If it is being used at the time you want to upload it also won't work. 

So before choosing to use OTAMP consider these factors, and know that you can always fall back and use the cable that works in all instances.



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