Which module for 1000x unit low range mesh

[Pinchy]

Hi everyone, I’m have a wired network of 1000 devices (relay switches) that I’ve been tasked to upgrade to wireless.

• Devices are inside a warehouse, about a pallet apart (~1m). So each device would be ~1m away from at least 4 others, 10m away from at least 40 others, all devices would be within a 100m radius of each other
• Devices are powered by wired 24VDC.
• Devices need to broadcast a "heartbeat" at least daily, no acknowledgement required
• ~50 devices need their state changed (on/off) every minute or so, acknowledgement required
• Each device is unique, rather than a group, so unicast messaging (or grouping IDs in a multicast message) may be required

I’ve used the nrf52832 before and liked it so would like to explore other Nordic options  

my question is, is the above problem solvable using Bluetooth 5? If so, which would be the cheapest module to use? What are some considerations to explore? Thank you!! 

[Kazi Afroza Sultana]

Hello Pinchy,

Good Day.

The issues  you mentioned above can be solved (except the one related to Device power) by using  Bluetooth 5 . As It (Bluetooth 5) introduces four times more range than previous version even without a need to increase peak output power. The ability to perform periodic and deterministic advertising, which allows scanners to synchronize their scanning for packets with the schedule of the advertising device. Therefore, periodic broadcasting is possible with or without acknowledgement. In Unicast messaging, the receiver has to Acknowledgement all the packets and if these packets are not acknowledged, this acknowledgement has to send again. 

Regarding device powered by DC 24V – none of our devices support that much voltage. For example: Supply voltage range of nRF52805 and nRF 52832 is 1.7V to 3.6 V. You may use a voltage converter for your system to be compatible with your required 24VDC. 

The nRF52 Series multiprotocol SoCs support Bluetooth 5 and the nRF52840 supports all new features of Bluetooth 5. For pricing, you can contact Regional Sales Manager(RSM) and/or Distributor  Contact us - nordicsemi.com  .

 To find specific module according to your requirement, you can look at this link https://www.nordicsemi.com/Nordic-Partners/3rd-party-modules

Hope it helps. 

Let me know if you would like to know more.

Best Regards,

Kazi Afroza Sultana

[Pinchy]

Thanks for the reply Kazi!

Not after a module - apologies I used that word - the cost won't be low enough for our application and we're happy to put a PCB trace antenna on the board.  Noted on the voltage, that was merely me stating that it's not battery operated and we don't care about "low power".

What I'm after is confirmation that Bluetooth 5 will work with a densely populated network of 1000 devices and if there's anything specific I need to consider.  This unfortunately is one of those difficult applications to test at a small scale as network transient effects like delays and collisions may only appear in large networks so I want to avoid that issue before manufacturing and installing 1000 devices!

Is the nRF52840 the most economical SoC to use?