Home/ Machine Talk Blog

Preparing for Wireless Design Certification

Knowledge is power, as they say. When building a wireless product, understanding and preparing for certification requirements can help optimize your design from the beginning so you can pass certifications on the first attempt. This article will cover the key certifications to prepare for as you begin planning your product design.

FCC certifications

Any product to be sold in the U.S. must pass FCC certifications, which include the following:

  • FCC Part 15, subpart B – Unintentional Radiator (EMI): Electronic devices with oscillations greater than 9 kHz that do not deliberately generate radio frequency emissions must comply with FCC Part 15, subpart B emission limits. Today, because devices have much faster clock speeds, this test can be difficult to pass. Faster clocks mean shorter wavelengths; as a result, smaller structures on your PCB can act as an antenna and propagate unwanted emissions. So you really need to minimize this noise in your electronics design.
  • Part 15C, 22, 24, 27 – Intentional Radiator: These tests assess output power and other signal characteristics for products with RF transmitters. Harmonics are the most common cause of test failure, and there are several typical reasons. Here are two common examples:
    Non-linear power amplifiers in the transmitter chain can generate harmonics which are then radiated by the antenna.
    Non-linear PCB components can pick up the fundamental frequency radiated from the antenna and then generate and radiate the harmonics of the fundamental frequency.
  • Specific Absorption Rate (SAR) –This test measures how much the product’s RF transmissions heat human tissue, and is designed to prevent health hazards. If the end product will be used within 20 cm of the human body, you must perform a maximum permissible exposure (MPE) calculation, at a minimum, to determine whether SAR testing is required.

Cellular certifications

Cellular over-the-air (OTA) tests are required for cellular designs with antennas located less than 20 cm from the radio, and are very challenging to pass. Cellular certification testing often includes the following, depending on carrier selection and geographic region:

  • Total Radiated Power (TRP) – Measures total power radiated from the device and is a function of the antenna radiation efficiency, impedance match, and radio output power.
  • Total Isotropic Sensitivity (TIS) – Measures radiated receiver sensitivity integrated over a sphere around the device. It is a function of antenna radiation efficiency, impedance match, and radio receiver sensitivity, but is often limited by noise radiated from host electronics.
  • Relative Sensitivity Intermediate Channel (RSIC) – tests for receiver sensitivity degradation on specific RF channels.
  • Radiated Spurious Emissions (RSE) – evaluates spurious emissions from the cellular transmitter as well as the host electronics

RF Engineering Manager, Kyle Sporre, summarizes PTCRB test requirements, and the regions where they are applicable in the simple whiteboard video session below.

It is very important to understand the design principles that affect certification testing early in your process and to apply best practices. Effectively controlling noise prior to performing radiated cellular tests such as TIS and RSIC can help you achieve the low EMI required to pass certification testing. TIS requires even quieter PCB emissions than FCC certifications, and failures caused by noise coming from the host electronics are common.

Note that products that do not include an antenna within 20 cm of the device are not subject to OTA tests. For example, this includes box products with an antenna port that requires the customer to supply the antenna, or products with cabled antennas that are more than 20 cm from the device. To ensure success, design your product up front with certification requirements in mind. If you need assistance, Digi’s Wireless Design Services (WDS) team can help with your product design, or even correct design issues that can lead to certification failures.

>>Check out additional information on  critical design considerations and the Digi WDS team to get certified today.

DimOnOff Improves Intelligent Lighting with Digi Mesh Network and IoT Sensors

Posted on:

In order to make street lights more intelligent and connected, DimOnOff created a Centralized Adaptive Lighting System also known as Central Management System (CMS), to centrally manage street lights across a city using dimming and other adjustment methods. This smart streetlight solution is compatible with LED conversion, as many cities transition away from traditional expensive high-pressure sodium (HPS) streetlights to more energy efficient LED fixtures.

This complete front-to-end smart wireless control system has saved cities 40-50% in maintenance costs, while other municipal customers have achieve their ROI within three years because they can better predict and prepare for what needs to be fixed and they are saving on energy costs due to the intelligent lighting system adjusting to the unique needs of a specific location. But, the biggest benefit is enhanced safety for citizens with streets that are safer for walking, riding bikes, and driving.

DimOnOff’s intelligent, addressable modules use Digi XBee wireless RF modules to communicate on a secure mesh network – the Digi DigiMesh® network solution. DigiMesh offers added network stability through self-healing and dense network operation while reducing costs to about $.04 per light pole, in comparison to $1.00-$2.00 using alternative technologies.

>>Read more results and see how DimOnOff’s SCMS platform is bringing new life to city streets.

Five New Features of the Next Generation of Digi XBee®

Posted on:

Earlier this week, the Digi XBee Cellular introduced three new variants to the lineup and announced the new features and upgrades of the module platform that combines global connectivity, built-in security, and design flexibility for Internet of Things (IoT) applications:

Digi XBee Cellular

Designed for Verizon, AT&T, and T-Mobile Cat-1 cellular networks.

Digi XBee Cellular LTE-M

Provide OEMs with a simple way to integrate low-power cellular connectivity into their devices.

Digi XBee Cellular NB-IoT 

Provide OEMs with a simple way to integrate low-power narrow-band cellular connectivity into their devices.

These advanced, smart, cellular modems strengthen the already robust Digi XBee product line and are capable of meeting all wireless needs – from cellular, to ZigBee, to Wi-Fi protocols. The platform offers complete design freedom for cellular IoT connectivity integration from LTE Cat-1 all the way to LTE-M and NB-IoT LPWAN technology.

With the new upgrades and features below, organizations looking to integrate cellular connectivity and the ability to standardize on one module platform with a single hardware footprint across products, regions, applications, and cellular networks for everything from local applications to global solutions – regardless of the complexity level.

  1. Programmability: Local intelligence programmed on the modem itself. Business rules engines and application logic can transform data, control local I/O, connect to Bluetooth sensors, actively manage utilization of the cellular link and optimize cellular data plans.
  2. Full USB Support: Supports wide range of applications, from basic to more complex Linux-based applications/systems; direct USB communication for apps with native control requirements.
  3. Bluetooth® Ready: Bluetooth Low Energy (BLE) and Bluetooth Mesh connectivity. Allows simple and quick local setup, provisioning, and troubleshooting capabilities using modern mobile phones and tablets.
  4. Advanced Manageability Features: Support robust over-the-air (OTA) firmware upgrades, Digi’s easy-to-use RF management and configuration tool Digi XCTU, and remote management through Digi Remote Manager™.
  5. Built-In Security: Hardened with built-in Digi TrustFence™ device security.

>>Find more information about the award winning,  next generation Digi XBee cellular products to get started today.

From Digi XBee Project to Life-Changing Robotic Limb Products

Posted on:

We first met Easton LaChappelle four years ago when he was only 17-years-old. Easton took us by surprise as a self-taught maker who set his mission on creating brain-powered prostheses powered by Digi’s XBee RF modules. Using 3-D printing and Digi XBees, Easton created what the market so desperately needed, a prosthetic that sold for less than $400, robotic nonetheless.

Easton not only taught himself but found the most useful tools to progress his mission. He used tools and “how to” resources he found in online communities to set himself free from limitations that often hold others back.

We weren’t the only ones to take notice. Today, at 21-years-old, Easton has worked with NASA on The Robonaut, and he’s now working with Tony Robbins, Microsoft, and others to make his dream come true. His company, Unlimited Tomorrow, focuses on making life-changing robotic limbs available and affordable for those who need it most.

It all started when he met a little girl with a prosthetic arm. He found out that her parents had to pay $80,000 for it—and not the ‘smart’ kind that Easton could then see was possible. Take a look at how far he’s come today:

“Easton is an absolute genius! He’s dreamed of transforming people’s lives through robotics since he was just 17 years old (I started funding him when he turned 18) and has turned his dreams into reality! Check out these life-changing results he’s creating with 3D-printed prosthetics!” Tony Robbins says.

To see more amazing Digi XBee projects and meet up-and-coming makers, visit the Digi XBee project gallery here.

You can also learn more about how to get started with Digi’s XBee product line here. >> 

Tags: , , ,
Posted in Maker, XBee | Comments Off on From Digi XBee Project to Life-Changing Robotic Limb Products

Tweeting Pet Bowl

Posted on:

Attention pet owners! Do you ever walk past your pet’s bowl and wonder how long it has been empty? On this #FlashBackFriday we go back to 2011 when Chris Monaco made a tweeting pet bowl using Digi XBee to solve this problem.

Using a force-sensitive resistor and two Digi XBee cellular modules, the pet bowl senses when the water level or amount of food in the bowl is low. It will then send a tweet to alert the owner that the bowl needs to be refilled – a complete wireless solution.

Have an awesome project to share or want to create one with a Digi XBee Cellular Development Kit? Follow and to get in touch with us.

Four Critical Requirements for Intelligent Water Management

Posted on:

When managing complex drainage districts, distributed lift stations or a municipal water treatment facility, networking and SCADA engineers are tasked with creating and operating safe, efficient water and wastewater management systems for their local and regional communities. In the challenging world of water management, application operating environments are commonly remote and harsh, which makes using 4G LTE wireless networks ideal for connecting remote assets. Below are four critical requirements to consider when upgrading to new technology and network management tools.

  • Equipment Reliability – How long is the warranty of your communication gear? Pumps, PLCs and RTUs are expected to last for years.
  • Flexible Networking Options – It is typical for municipalities to designate a primary and secondary, backup cellular carrier for SCADA telemetry equipment installed across a wide geographic area. The ideal 4G LTE device will support software-selectable carrier switching.
  • System Security – 4G LTE devices and management tools must support guidelines and requirements for water management systems as defined by the Critical Infrastructure Protection (CIP) Act in the U.S. and similar legislation in other countries. It should also enable enterprise security features like access-controlled ports, encrypted data storage, authentic boot and firewalls, as well as connections to security equipment such as IP cameras.
  • Remote Management – Once devices are installed and systems are operational, the challenge of operating a network of distributed telemetry equipment begins. Remote configuration, monitoring and troubleshooting tools are essential.

>>Check out our 4G LTE solution for Water/Wastewater Telemetry and SCADA applications.

University of Minnesota – Solar Vehicle

Posted on:

In 1990, a group of undergraduate students at the University of Minnesota established the Solar Vehicle Project so students could experience engineering and management in a complete product development environment. Over twenty five years and twelve solar cars later, the University of Minnesota’s Solar Vehicle Project became the first team from the United States to compete in the Cruiser Class of the 2013 Bridgestone World Solar Challenge in Australia. Since then, they returned to this biennial event with their new EOS I solar vehicle in 2015 and were the only cruiser competitor to qualify for both the 2016 Formula Sun Grand Prix and the 2016 American Solar Challenge. The team will be returning to the Bridgestone World Solar Challenge with their new Eos II solar vehicle on October 8, 2017.

Looking to improve the practicality and efficiency of their cruiser vehicle, the University of Minnesota team of approximately seventy-five undergraduate students, has spent the last two years planning, designing, fundraising, and building the Eos II solar vehicle using Digi XBee modules to communicate and log data from the solar car and lead vehicle. In support of these innovative efforts, Digi has sponsored the solar team with four Digi XLR Pro radios to help the team members communicate and log data using a point-to-multipoint Ethernet bridge to create a transparent network connecting computers and networked sensors in all vehicles and the caravan. The team will also have the ability to access locally hosted resources on a dedicated server in the lead vehicle, something they have not been able to do in the past.

Yesterday, we had the honor of meeting the 2017 crew to hand deliver the Digi XLR Pro radios. The energetic and excited team gave us an inside look into their shop, showed us under the hood of the EOS II, and tested out Digi XBee modules while test driving the solar vehicle. Stay tuned for more updates coming soon and be sure to follow this brilliant, hardworking, and fun team on Twitter to cheer them on!

Fill out this simple Digi XBee Project form to feature your project on the Machine Talk blog for a chance to win a free Digi XBee Development Kit.

Simple Garage Door Sensor

Posted on:

Table of Contents


  1. Introduction
  2. Assembly of Parts
  3. Configure the Radio
  4. View It
  5. Use It
  6. Intern Spotlight


Whether you’re pulling into work after a busy morning, driving to the family cabin, or just laying in bed after a long day, the last thing you want to worry about is your car garage door. This example will show you how to install a simple garage door monitor so you never have to worry if your garage door is left open. Using the Digi XBee LTE Cat1 Development Kit and a magnetic reed switch, an SMS can be sent to your phone notifying you if your garage door is opened or closed.

Contact a Digi expert and get started today! Contact Us
Have a Question?