Tag Archives: RF layout and design

RF Modules: A low risk path to wireless success

It is rare for a day to go by without having at least one conversation with an embedded developer, project manager, Maker / hacker or hobbyist where the subject of the Internet of Things (IoT) and/or wireless connectivity does not come up in discussion.

Today, IoT is certainly a major focus in product development and wireless is a major component of that solution. Usually, my conversation centers around comments from product developers regarding how difficult it is to develop a production ready wireless product on the first pass; it is especially difficult for the growing number of product developers or Makers that are just getting their feet wet in wireless design and development.

Only the very experienced RF designers are willing to start from scratch when beginning a new wireless product design. For the rest of us, we look for proven reference designs and more recently, the first thing we browse for is an off-the-shelf certified module.

In comes Atmel! The company has recognized for a while that RF modules provide a low risk path to success, for those seeking to add wireless connectivity to their product. And, it is this realization that has led to a growing family of RF modules to meet one’s wireless needs in Wi-Fi, 802.15.4, and BLE coming soon.

Examples of 802.15.4 Zigbit wireless modules.

The certified wireless module approach turns a complicated RF design task into an easier, more manageable digital peripheral interface task. Don’t misunderstand me, one still must be careful and adhere to best practices in your embedded PCB design to support an RF module; however, it is a much easier to be successful on the first go-around when using an RF module than it would be starting from a chipset or IC layout and design.

typical wireless module

A typical wireless module with on board “chip” antenna (white rectangle shown in image).

For the most part, the layout of impedance controlled traces, and antenna layout and matching are all taken care of for you when using a module. Usually, the most difficult thing you have to consider is placement of the module on your target or carrier board, such that your placement does not adversely affect the radiation pattern or tuning of the antenna.

Not only does the design become simpler, but the costs associated with getting a wireless device to market becomes lower.  Because in general, all of the fees and time associated with governmental certification testing for agencies like the FCC, CE and IC (Industry Canada), are already taken care of for you. Also in most cases, the modules are shipped with a unique IEEE MAC address pre-programmed into the module’s non-volatile memory, so that each unit has a world wide unique address. By using a module that contains this pre-programmed assigned address, you can avoid the costs of obtaining a block of IEEE addresses assigned to your company.

At first glance, the cost of using a complete pre-certified RF module in a production design, as compared to implementing one’s own chip set design may appear more expensive. However, for those doing this for the first time with a staff that does not have a lot of RF design and certification experience, the hidden costs and time required to achieve the performance your application requires and to get the product into the market, leads to a lot of unwanted surprises requiring multiple attempts to achieve the final goal. Starting with a module helps get the product into the market faster with less risk, and provides a way to get product acceptance, before having to deal with cost reduction activity’s that may require moving from a module solution to a chip set solution.

For those that get to the position where the use of a pre-certified module on a proven product requires a cost reduction, Atmel has a solution ready for you. Each of the Atmel Zigbit modules have complete Altium design files and Gerber files available for free download via the Atmel website. This will enable you to take the exact design files that were used to create the module you were using or considering, and to use these files to devise your own version of that design. You can then have your new chip based layout manufactured by your own contract manufacturer; thus, you do not have to start over from the beginning and you already know that this RF design works well and can be easily certified. Governmental certification of your own board layout would be required, and in the case of the United States, you would be given your own FCC ID assigned to your company for this product.

For those product designers that are experienced in RF layout and design, a module can allow you to create a proof-of-concept product prototype very quickly and with little effort. Once the concepts have been proven and features have been decided upon, you can migrate from module to chip set design for high volume production.

Software developers, Makers, and hobbyists can eliminate a lot of the issues often found when trying to create low volume wireless products by obtaining one of the many Atmel evaluation boards that contain a wireless module.

These boards typically come with a bootloader and with some form of pre-loaded firmware to get you started immediately. You can explore that topic in more detail in an earlier Bits & Pieces post that describes the wireless composer and the Performance Analyzer firmware.

The Performance Analyzer firmware is what typically comes pre-installed on a Zigbit module “evaluation” board. Otherwise, the module itself would come with only a pre-programmed bootloader.

module evaluation board

You can learn more and download user guides / datasheets for the Atmel Zigbit modules via this link.

With the Internet of Things becoming such a focus at this time, you may want to get started with a pair of low-cost wireless module evaluation boards and use this platform to learn wireless connectivity techniques that can be used in your current or future job.  Demand for those with knowledge and experience in wireless connectivity and embedded systems is growing greater everyday.

Whether you’re a Maker or an engineer that wants to create a home project that requires a microcontroller and some type of wireless connectivity, you might want to take a look at the ATZB-256RFR2-XPRO evaluation board that includes the ATZB-S1-256-3-0-C module already mounted on it. This module is based upon the megaAVR microcontroller core and includes an 802.15.4 2.4ghz radio as a peripheral/.You may recognize the megaAVR core as being the same MCU core as used in the well-known and incredibly popular Arduino Uno board. You can use the familiar Arduino IDE for development and many of the Arduino libraries available on the internet will run directly on this module. Additionally, you can also find a bootloader and sample Lwmesh (Light Weight Mesh wireless networking) applications for this module here. (Search for for “ATmega256RFR2 Arduino Solution.”)

Look to our friends at Adafruit and Sparkfun to obtain various sensor breakout boards to complete your wireless connectivity projects.

Do you have big ideas? You can feel confident that with the 256k of flash program memory and the 32k of data sram available with the ATZB-S1-256-3-0-C module, as you will be able to create any Arduino application that comes to mind. And don’t forget, you have an onboard 802.15.4 2.4Ghz radio for your wireless connectivity needs. If you find you need additional features in your development and debug tools, you can simply move to Atmel Studio with its rich set of features.

Calling all Radio Amateurs CQ CQ CQ de NS1C… 

Are you now, or have you been in the past, involved in Amateur Radio? Have you been dreaming about QRP low power radios that are very small, battery operated, a complete radio solution, and cost in the $29 to $39 dollar range? You’re in luck — boards and modules are available that operate in the 915mhz or 2.4ghz radio bands! As a HAM radio operator, you are allowed to take the capabilities of these 802.15.4 radio modules even further than an engineer who is required to create a license free ISM radio solution. You can experiment with additional RF output power and experiment with high gain directional antennas (use the modules with u.FL RF connectors).

Maybe a nice field day project for next year would be to use a low power 15.4 radio from the top of a mountain or high hill and use mesh networking to see how many hops a group of participants can communicate over. Voice communication certainly could be implemented using external analog circuitry and some additional software; however, when getting started, you could stick to digital data communications or use the wireless microcontrollers to control or monitor other components of your Amateur radio station.

Parents teach your children…. or maybe, children teach your parents!

I am sure that everyone can think of many home or science fair projects where a parent and child can work together (hardware / software / documentation) and everyone can learn something new. Heck, in the end, you may actually invent the next great product that your family can introduce to the world!

Your possibilities are endless.