This week’s EYE ON NPI (video) is super phat not unlike a pair of ultra wide JNCOs, it’s the Laird Sera NX040 Ultra-Wide Band and Bluetooth Combo Module, a compact solution that combines the best of NXP UWB and Nordic BTLE into a single easy-to-use module that is ready for instant integration into your location-based identification products or projects.
We often get folks asking how they can do indoor location projects: where an object is tracked in a 2D or 3D space, with high precision. For outdoor projects, most people use GPS/GNSS which can give 10 meter accuracy anywhere in the world. Or, sometimes people use cell tower triangulation to give rough estimates of location world-wide.
However, both of these require you to be outside, with either network connectivity or a GNSS fix – and like we mentioned, you can’t get better than 10 meter accuracy without very expensive RTK modules. Indoors, sometimes its possible to use WiFi time-of-flight, or BTLE ToF / AoA.
There’s a great “UWB Minutes” video series available from NXP that covers how ultra wideband (UWB) is used for localized-scale object detection. Basically, if you just want to do a simple “how far are you” type detection, you only need one station and any number of mobile detectors.
The station sends a wide-band pulse that spans approximately 5 to 8 GHz. By measuring the time it takes to get a response, as well as the phase shift and amplitude of the returned signals, we can determine if we are in a direct line of sight or non-direct – in which case some math can be used to try and determine the actual distance.
More interesting, we can also use multiple stationary transmitters to determine the 3D location of a mobile device. Instead of looking for one pulse, we encode the transmitter ID into the pulses, and then can correlate each received pulse to the fixed 3D location of the station. As long as we have 4 stations, we can solve for XYZ and, yes, that’s a lot of stations, but you can get 10cm accuracy, which blows away BTLE and WiFi RSSI or ToF methods.
Note that doing the triangulation on UWB pings requires a ton of math which is why having a ready-to-go module is great because NXP and Laird will provide example code to get you started.
While most folks think of UWB as a 3D locator, NXP promotes some other use cases – most notably peer-to-peer payments and keyless car access.
The keyless entry proffer is the most timely as there’s been a spate of car theft rings that use relay attacks to amplify the signal from a keyfob. If the car is parked close to the house and the keys are kept near the door.
Thanks to UWB now being included in iPhones and in the iOS API, you can likely have customers use their iPhones to directly interact with the Sera NX040.
To save you time and integration costs, the Sera NX040 includes the NXP UWB chipset and all supporting circuitry, plus a Nordic nRF52833 which is a Cortex M4 with all the peripherals, plus the best Bluetooth LE radio on the market. Nordic’s chips are especially good at low-power use-cases so battery-powered designs will benefit from this combo. The NXP SR040 is wired to the nRF via SPI – you’ll use the NXP SDK for that, which you need to contact NXP for. Or you can use the Laird MicroPython build which comes with some ready-to-go examples.
The Seras are available with either built in tuned antenna or a external antenna connection – you’ll need to pick up a NanoUWB antenna to match.
As you can expect for a device with two wireless components, proper layout is essential to get good performance from both the BLE side and the UWB side – check the Laird documentation on how to set up keep-outs and ground planes.
Finally, if you want to get started you can always pick up the NX040 Eval Board which has SWD debug for programming the nRF, USB connection for MicroPython or Zephyr debugging, and a separate RP2040+MikroBus+Qwiic half that can be used for adding sensors or displays.
Whew, this NPI was not just ultra-wide but ultra-long: we learned a lot while researching the Sera NX040 and the modern uses of UWB! If you want to get in on this multi-purpose RF protocol, you’re in luck because DigiKey has the Laird Sera NX040 UWB+BTLE Module and accessories in stock right now for immediate shipment. Order today and they’ll send you parts faster than an UWB pulse so you can get started with integration in nanoseconds.
See the EYE on NPI video:
See the NXP video: