Tag Archives: Wireless Composer

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.

Accelerate your evaluation of Atmel 802.15.4 wireless solutions from your desktop

You have probably come across this scenario before: Management or the marketing department approaches you asking you to add wireless functionality to an existing product, or to develop a new product that needs to be able to support a wireless link. Today, there are many wireless technologies and options to consider.

It is also quite possible that marketing has already made part of that decision for you.

The marketing requirement may stipulate that you use Wi-Fi, Zigbee, 6lowpan or Bluetooth low energy (BLE). Or, maybe marketing has no idea what is required, and just tells you to implement a wireless link!

So, after a number of meetings and conference calls, you decide to use a solution that is based upon 802.15.4. This could include Zigbee, 6lowpan, Wireless HART, ISA100.11a, Openwsn, Lwmesh, among many other wireless stack solutions that all require an 802.15.4 compliant transceiver.

At this point you would need to decide if your solution, or the protocol you’ve selected, will operate in the 2.4 GHz band or in a SubGhz band. There are times when you will need to do some experimentation or RF performance evaluations to determine which RF band to use in your particular situation.

When evaluating Atmel 802.15.4 wireless solutions, the first tool you should turn to is Wireless Composer. Provided as an extension to Atmel Studio 6.x, the Wireless Composer is a free tool. In order to make it simple, each of the current Atmel 802.15.4 evaluation kits/platforms comes with a Performance Analyzer firmware application pre programmed into the kit. Running on the evaluation kit, this Performance Analyzer firmware is designed to communicate with both the Atmel Studio and Wireless Composer extension.

Some of the capabilities of Wireless Composer include:

  • PER (Packet Error Rate) Testing: Transmit and receive 1000’s of frames at a specific TX power level and RF channel and then review the results for errors (dropped bits/frames) while also evaluating throughput metrics.
  • CW Test Modes: Place a device in a Continuous test mode to monitor emissions with a spectrum analyzer or other RF test equipment
  • Antenna Evaluation: Provide a Large Digital Display to allow testing antenna radiation pattern’s at distances of up to around 3 meters from the device connected to the laptop PC.
  • Range Testing: Gather and log range data generated from a  wireless link set up between two nodes — this data includes RSSI (ED signal strength) and LQI (signal quality) from both sides of the RF link.

Here are a few additional example screen captures, available from within Wireless Composer.

Energy Detection Scan Mode:

Energy Detection Scan

Screenshot of Wireless Composer, an extension of Atmel Studio 6.x – Energy Detection Scan

Have you ever wanted to set up some RF tests and wanted to know if there were other transmissions already taking place on the channel you intended to test on ?  Maybe your colleagues  are performing tests in another section of the lab or building, or maybe at home you have Wi-Fi or Bluetooth or home automation devices operating in close proximity to where you want to run some experiments.  The ED scan mode, as shown here, allows you to get a quick glimpse of what RF activity is happening around you. You can do a one time scan or you can configure the test to continuously scan one or all channels and repeat this until you stop the test.

PER Test:

A common RF test to perform on a packet based wireless communication system is a PER (Packet Error Rate) test.

This test mode allows you to configure operation on a particular channel, at a specific TX power level, using a selected antenna option. You are then provided the ability to set the number of bytes to send in a transmitted frame, and to set how many frames you are going to send during the test. All of these parameters are configured in the left hand Transceiver Properties Pane, as shown in the capture below. Once the test is performed, the right hand window provides data regarding the results of the test.

This can be useful for confirming RX sensitivity parameters, and data throughput characteristics under different conditions. Here is an example of sending 1000 frames and achieving zero errors using a frame length of 20 bytes.

Packet Error Rate test mode

Screenshot of Wireless Composer, an extension to Atmel Studio 6.2 – Packet Error Rate test mode

 

Continuous Transmission Test Mode:

If you have attempted to develop a wireless RF product before, you know that a considerable amount of time will be spent performing regulatory pre – scan certification testing. This typically involves configuring your device to transmit a continuous wave RF emission on a particular RF channel using a specified amount of Transmit power. The RF emissions are monitored using a spectrum analyzer or other RF test equipment. To help save time and provide a useful tool, Wireless Composer provides a Continuous Transmission Tab that allows selection of a few different tests of this type.

In the example shown below, an unmodulated CW test transmission has been started on channel 16 using a TX power level of +4dBm. These are no results reported here, because all measurement results would come from observing the RF test equipment that monitors the RF emissions.

Screenshot of Wireless Composer, an extension to Atmel Studio 6.2 -  Continuous Wave test mode

Screenshot of Wireless Composer, an extension to Atmel Studio 6.2 – Continuous Wave test mode

 

Antenna Evaluation Range Test Numerical Display:

For any wireless product, the antenna is one of the most important sections of the design. A great radio with a poor antenna results in poor product performance, while a mediocre radio with a great antenna can end up with very good performance. So, one of the tasks for any wireless product developer is to understand the characteristics and performance of his antenna design. This may be some type of on board antenna like a ceramic chip antenna, or a pcb trace antenna, or it just may be connecting an external antenna to an RF connector mounted on the product’s pcb. Many on board antenna designs are shortened quite a bit to reduce the footprint or space required by the antenna. This usually will affect the performance of the antenna in a negative way, or at a minimum create directivity to the antenna’s radiation pattern. A nice capability of Wireless Composer is the ability to allow you  to place the device connected to the PC, running Wireless Composer, on a table or tripod at a specific height above the floor in an open indoor or outdoor area. Then, in the range test tab within Wireless Composer, select “Numerical “ as the display mode. This will then display a screen as shown below.

One would then take a battery operated mobile node about three meters away from the PC display and watch the values being displayed for ED/RSSI and LQI change as you rotate or change the orientation of the antenna with respect to the unit at the other end of the link. This display shows the LQI and ED/RSSI values at both ends of the link and can be used to examine any changes in antenna pattern, as the device orientation is changed. Knowing what orientation provides the best signal levels will later help you understand how to position the unit when mounting it at its final location. You will also acquire information on how to set up additional range tests where you could be up to one mile away, and all you have is a blinking led to indicate whether or not you still have communications with the unit under test.

Screenshot of Wireless Composer, an extension to Atmel Studio 6.2 - Range Test Numerical Display

Screenshot of Wireless Composer, an extension to Atmel Studio 6.2 – Range Test Numerical Display

 

Range Test Log With Multiple Markers (Push Button Marker Recording):

Wireless Composer also has a range test mode for logging signal level and quality to a PC display or to an Excel file, as shown in the screen capture below.

When two paired devices are configured in this range test mode, the unit connected to the PC will periodically (about every two seconds to conserve battery life) send a beacon type frame to the mobile unit, at which point the mobile unit will send back a reply to the logging device. This activity can also be seen in the screen capture below.

The LQI and ED (average RSSI) levels for each side of the wireless link are recorded with a time stamp to an Excel file.

Have you ever tried to do an RF range test by yourself? If you have, then you know that it sometimes can be difficult to set up a test, such that you can leave one node at a fixed location and take the other battery operated mobile unit to various locations where you want to gather signal level and link quality information.

This is especially true when your simple wireless device lacks any type of user interface, or display attached to it, as in the case of a wireless sensor, or an simple evaluation board. This becomes even more difficult if you are doing LOS (line of sight) measurements outdoors. The performance analyzer app only assumes you have access to two IO pins — one is typically an input for a push button or jumper, while the other is an output for an LED.

Outdoor LOS measurements may allow you to achieve distances of hundreds of meters, as well as one or more miles in the SubGhz RF bands.

To make this measurement task a lot easier, the performance analyzer app has the ability to enable you to press a button on the battery operated portable unit that you have in your hand, and have this RF device send an RF frame back to the unit connected to the PC that is doing the logging; as a result, that marker frame is recorded into the log, allowing you to place marker indicators for time and place in the log file. This will enable you to determine where you have been when you return to review the log data.

For instance, you could press the button once while at a specific location in room A, and then press it twice in for a location in room B. Or, if you are outdoors you could press the button and insert markers at various distances as you move away from the logging unit. Then, all you would have to write on your notepad while doing the test would be the name of your location (or the distance at which you were away from the logging unit) and the number of times you pressed the button at that location.

Upon your return to examine the recorded log, you’ll have all of the necessary information to understand the recorded results, including where in space and time the measurements were made.

See the example below:

Screenshot of Wireless Composer, an extension to Atmel Studio 6.2 -  - Recorded Logs

Screenshot of Wireless Composer, an extension to Atmel Studio 6.2 – – Recorded Logs

 

For each of the supported wireless platforms, Atmel Studio contains complete example projects with source files for the performance analyzer application. When you are finished making measurements on an Atmel evaluation board that you used to help make device selection or RF band selection decisions, you can then use this same application with possibly some minor modifications to support your own final hardware design with regards to the IO assignments for a push button or led. This performance analyzer application along with Wireless Composer have proven to be very useful when performing tests on first prototype boards, and even for use in performing FCC or other governmental regulation pre-scan testing.

Interested in learning more? You can access Wireless Composer here and Atmel Studio here.

 

 

Atmel introduces next-gen ZigBit wireless modules

Atmel has introduced its second-gen lineup of ZigBit wireless modules. Based on the company’s latest wireless transceivers and wireless microcontrollers (MCUs), the new ZigBits offer a wider range of features and reduced power consumption.

zigbit1

According to an Atmel engineering rep, the ZigBit modules – equipped with an integrated chip antenna – can be easily installed in a variety of devices without the need for any RF design or RF layout expertise.

“Simply put, the wireless modules offer customers a complete out of the box wireless system, pretested and certified for FCC (North America), ETSI (Europe) and IC (Canada),” the engineering rep explained. “This is because the second-gen ZigBits facilitate an optimized design path from evaluation to development, testing and certification, up to the final wireless end-product.”

zigbit2

As noted above, Atmel’s ZigBit modules can be easily integrated in a wide variety of devices including wireless sensor and control applications; lighting control; home automation; thermostats; occupancy sensors and home displays; environmental monitoring and proprietary wireless systems up to 2000kb/s.

In addition, support for the second-gen ZigBit wireless modules has been added to the Wireless Composer, which is available via Atmel’s Gallery. Essentially, the Wireless Composer provides devs with a performance analyzer application – complete with intuitive displays to configure, command and monitor test data originating from the target device.

“The GUI is used to configure and execute packet error rate testing, perform energy density scans on the available channels and perform FCC testing for setting the device in continuous transmission mode,” the Atmel engineering rep continued. “The Wireless Composer supports all Atmel RF devices and can be easily adapted to execute performance measurements on the customer’s board.”

ZigBit wireless modules are available at Atmel’s official store and via local distributors, while samples can be ordered using the “Free Atmel Tools” service.The modules ship in single quantities and tape & reel of 200.

As we’ve previously discussed on Bits & Pieces, Atmel also offers developers a lineup of ZigBit Xplained PRO extensions and USB sticks for evaluation and application development using ZigBit wireless modules.

zigbitxpro

Basically, the ZigBit Xplained PRO extensions are designed to interface with any Atmel Xplained PRO series of evaluation boards using the standard 20pin connector. Of course, the boards can also act as a standalone wireless node using an external battery case.

zigbit3usb

It should be noted that ZigBit Xplained PRO extensions ship preprogrammed with a bootloader and Atmel’s Radio Performance Analyzer application for easy evaluation of key features and RF performance. The same goes for ZigBit USB sticks, which are ideal for use with the Wireshark packet sniffer available in Atmel Studio 6.

The ZigBit Xplained PRO extensions and ZigBit USB sticks are available at Atmel’s official store and via local distributors.