Custom Wireless Sensor Design

Many real-world sensor applications require some sort of custom element, particularly those that are intended for high volume use. One of the ways Radio Bridge differentiates is the ability to create custom wireless sensors quickly and cheaply for our end customers.

All of the original design work for Radio Bridge products has been performed in-house including the electronics, firmware, RF circuits, antennas, mechanical enclosures, cloud software, etc. This allows our team to very quickly and efficiently develop wireless sensors according to custom needs.

Customers often tell us they like our standard sensor X, but they also need it to do A, B, and C. Often the prototype can go out in just a few weeks if not days, depending on the level of complexity.

Common requests include:

  • Combining sensor types into one device
  • Making a small behavioral change in the device firmware
  • Custom form factor for hardware to fit inside customer’s enclosure
  • Adding a new sensor type

All Radio Bridge designs are “modular” meaning we can mix and match sensor types fairly easily to accelerate the development process.

The engineering team at Radio Bridge has many years of experience developing a variety of sensor types, and just because something isn’t listed on the website doesn’t mean it can’t be added fairly easily. In fact, we have a number of sensor types that have already been prototyped and can be leveraged into a full product design if needed.

 

CONSIDERATIONS FOR LORAWAN SENSOR DESIGN

Besides the RF and other wireless considerations discussed in the next section, development of LoRaWAN devices requires extensive industry experience. There are freely available code bases and reference designs for LoRaWAN end devices, however, new users find that there are many subtleties of this protocol that will cause reliability issues in the field if they are not addressed up front. A few examples may include:

  • How do you handle the case where harmonics of your uplink signal transfer to nearby (but incorrect) wireless channels?
  • How do you recover if the network server sends your device an incorrect channel mask?
  • How do you handle the case where the sub-band of the gateway / network server changes randomly in the field?
  • How do you handle the case where the downlink configuration is corrupted and the device attempts to connect to the LoRaWAN network in an unknown state?

These considerations number into the hundreds, and Radio Bridge has worked through all of these over the years. By being early adopters of LoRaWAN technology and obtaining field testing time across all major gateway vendors, network servers, regional frequency bands, and other variables, we can ensure that the core IP of Radio Bridge sensors will be rugged and reliable.

 

CONSIDERATIONS FOR RF CIRCUIT DESIGN AND WIRELESS SENSORS

Radio Frequency (RF) circuit design requires knowledge and experience in the wireless domain. Many engineers mistakenly believe that they can simply follow a reference design and then later find that their RF circuit performs very poorly or not at all. Understanding the physical characteristics of the medium or materials that the circuit is design on, the environment, the enclosure, ground planes, antennas, etc all factor into the efficiency of the radio and subsequent certification of the product. Knowledge of FCC and other certification standards is critical as is the equipment needed to properly tune and test your circuit prior to entering a certification lab.

Radio Bridge has extensive experience in RF circuit design:

  • RF tuning
  • Impedance matching
  • Antenna selection and/or design
  • PCB materials
  • Controlled impedance layout
  • Sub-Ghz experience in the 300MHz – 900MHz bands

 

PRICING AND NEXT STEPS

For a combined device (multiple sensor types in one), we typically recommend using multiple devices from our standard product portfolio for initial testing, and then a commitment on MOQ (minimum order quantity) will often be sufficient for us to move forward with the combined device design.

Minor changes to the firmware are often fairly simple, and again, a small commitment for a minimum order quantity is often all that is required. This may include custom payload structures, custom data conversions, custom reporting requirements, or countless other tweaks necessary for seamless integration into the end customer’s system.

Modifying the PCB hardware can also be a straightforward task, however there may be additional costs for prototyping, test fixture development, FCC certification, etc. In this case there will usually be a small NRE (non-recurring engineering cost) to cover these expenses.

For most custom designs, you will be given a unique part number that you can reference for convenient volume purchasing. Contact our sales team to discuss your requirements and receive a custom quote: sales@radiobridge.com

LoRaWAN System Design
Radio Bridge can develop the full sensor-to-cloud system built on LoRaWAN. This would include any customizations to sensors, gateways, network server, and user interface. The full system would be delivered to you with training and support.
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IoT Data-as-a-Service
Reduce up-front capital costs and only pay for the data you need.
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Questions for New IoT Designs

COST

Is this a high-volume application with minimal component costs and cloud management / network fees or low volume with minimal design costs?

LOW POWER

Are the devices battery powered and how long should they last without servicing?

EASE OF USE

Is the end user a typical consumer or only individuals with technical experience? Who is provisioning the devices and setting up the network?

SCALABILITY

Will there be millions of these devices connecting to the cloud or just hundreds?

SECURITY

What are we securing against and what level of security will be required? Are there industry driven security requirements?

SCHEDULE

What are the deadlines to bring this to market and are there make-vs-buy tradeoffs that can be made to get it to market faster?

CERTIFICATION

Which compliance and safety certifications will be required for this product including coexistence of multiple wireless components?

MECHANICAL

What are the size, shape, and other physical requirements of the system? How does the enclosure affect the antenna?