QM35825 potential industrial sensor use-case

Wireless Connectivity Ultra-Wideband
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Hi,

I’m currently researching if QM35825 or DM3000 are good technology candidates for only data transfer of sensor data (e.g. IMU). The use-case will be in an industrial environment/machine where reliability, synchronization, throughput and latency are of great concern. The use-case we have consists of one controller node and multiple (2-8) controlee nodes/sensor nodes configured in a star topology. The high level idea is to use some TDMA scheduling where controlee nodes join the network controlled my the controller. Then each controlee node is assigned a slot to transmit its data to the controller node.

So my question is:

  1. I see FiRa offers Data transfer, HUS, OWR AM, DL-TDOA, and TWR modes. Which mode is most useful in my use-case? (I would think Data transfer or HUS).
  2. Could this use-case be realized using QM35825 with the FiRa Protocols? I see taht UQT and cherry don’t support Data transfer or HUS, how could we best evaluate these modes? Should we write our own program using UCI commands and if so, how can we potentially set this up?
  3. Or do we need to look at developing our own MAC and application layers to support this kind of use-case and if so, which development platform is best suited for this (DW1000, DW3000, or QM35825)?

Thanks in advance,
Martijn

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As you deduced, this requires a scheduled system with dedicated slots for the transmissions. This implies some sort of shared network time that each node has to sync to. Any sort of Aloha style network won’t do.

An issue with the QM35825 is that it is a closed UWB system, so implementing your own MAC level protocols likely isn’t feasible.

The QM35826 is a more open version of the QM35825 but public data on that chip is limited at the present time.

For DW1000, DW3000, QM33000 chips, you can implement your own MAC layer since you are given raw access to the MAC/PHY.

If you are willing to consider a commercially available system, we will soon have what you are looking for in our CUWB 300 series system which is based on the QM33110W.

A single AN302 anchor would serve as the controller node. Operated in Multitime mode (TDoA like), it synchronizes tags and everything has a defined slot. It communicates and is powered by PoE Ethernet and would need to be within range of the other tags.

We will soon offer a PT302 tag which is otherwise identical to the PT301 but with a 9 axis IMU. The system would allow collection of IMU data which is sent back in data in each beacon. We support up to 100 Hz beacon rates. At that rate, with IMU data, we can support over 25 tags, so that is more than enough to cover 8 controlee nodes. If you have more than one machine, the single controller node can be used to serve 3 of them.

The IMU rates could be higher than 100 Hz, in that case, more than one IMU data set will be in each tag beacon. The IMU samples are timestamped in the global network time, so you can compare them among all the tags and put the data in sequence.

The actual IMU chips will be ST LSM6DSV for accel/gyro and LIS2MDL for magnetometer.

If you need other sensors than the IMU, the tag has a USB-C CDC serial device port which can transfer “user data” through the UWB system. This requires a USB host to send the data.

There are possible customizations to interface the tag to other sensors if you need them. This can run the range of tapping the USB signals for GPIO all the way up to a full custom PCB with the form factor and IO you want.

Mike Ciholas, President, Ciholas, Inc
3700 Bell Road, Newburgh, IN 47630 USA
mikec@ciholas.com
www.cuwb.io

1 Like
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Where did you get information about such a chip?

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Is there any information available of this chip? Also, does anyone know someone who is trying to develop their UWB solution around the QM35825 IC?