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A short note on Bluetooth® wireless technology IIOT vibration sensor power, range and battery life

As all IIOT sensors were not born equal, there has been much ‘talk’ about actual Bluetooth® wireless technolog range and, in particular, a product’s stated battery life versus its real battery life (some parallels with electric car stated mileage ranges, perhaps?). We typically get no less than a 50m range in a factory full of stainless steel. Here’s a short note on Bluetooth® wireless technology IIOT vibration sensor power, range and battery life – a quick read on what we at DIAGSOL (creators of the uBlock IIOT sensor) feel are the most important engineering aspects.

#1 dBm power of the Bluetooth® wireless technology chipset/ keeping the antenna clear of metal base and battery

We spent some time and selected an 8dBm power chipset as the best wattage versus power drain.

#2 Advertising interval / you need to be able to connect to the device

We chose three seconds to ensure you can walk up and connect within 10 seconds as the ideal.

#3 Comms method

Many developers use the Linux DFU/BlueZ libraries; we developed a programmed USB serial comms antenna
system that has very few crashes, actually halves the power use and reduces the loss of data to virtually zero.

#4 How often you ask for data and the size of the data packets acquired and transmitted

We believe a good daily measurement with better than 1Hz frequency noise bandwidth is more than sufficient, however, the data block has to be threshold tested to ensure the asset is running (we try 3x per day).

#5 The mAh rating of the battery used within the device

We selected a SAFT 1200mAh 3.6V Li-SOCl2 1⁄2 AA-sized battery as the best quality/ capacity battery

The Results

(Note – we log the comms times in our intelligent gateways & assess the power using the nRF toolchain)

uBlock Power Use (always TX @ 8dBm, 3 second Advertise)
Advertising/ Awaiting Comms 16uA @ 3.6V
TX & RX Bluetooth connected 7.5mA @ 3.6V
Per threshold test 3 blocks of 32k/ 12800L data
Linux DFU/BlueZ comms 6s/ 10s 40s/55s
Programmed nRF USB Serial comms 3s/4s 15s/22s
5 Year Power (1 x 3 axis data set per day, assumes acquires on 3rd threshold test) % of 1000mAh
Using DFU/BlueZ Within 20m 89% 50m or more 100%
Using nRF USB Serial Comms Within 20m 74% 50m or more 78%

Note – using BlueZ; likely to only get two out of three data sets sent.

Want to find out more? Get in touch for an informal chat about your requirements!

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