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Think I have sensors all around a car. In stead of physically wiring those sensors to a central computer, I want to add a battery to them and have them communicate wirelessly to my main control.

My question is what Wireless Protocol (for the Physical layer) can I pick?

Therefore my requirements are:

  • No Pairing should be needed. Sensors and controller come up and can discover all sensors and start getting data.
  • There could be multiple cars next to each other and the controller in each car should be hard paired to the sensor in its own system only.
  • What steps would be needed during initial installation to pair the sensors and the controller?

Update: As pointed out, items #1 and #2 above seem contradictory. Here is what I can afford. During the initial installation of the system, The factory integrator can scan the sensor 'remote sensor boards' and add them to the controller boards non volatile and select type and location of sensors. So I can afford to do pairing in the beginning. My question is - is Bluetooth a good choice for an application like this? or should i be looking at other protocols too? (I'm a hardware guy so trying to grasp the software stack abilities & requirements)

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  • \$\begingroup\$ Your first two requirements seem to be directly contradictory. Or are you using "pairing" in two different senses? \$\endgroup\$ – Dave Tweed Jun 6 '17 at 20:39
  • \$\begingroup\$ Points 1 and 2 are kind of contradictory, but it's a solved problem with whatever TPMS does. Usually though, CANBUS is used for things like this -- are you sure you won't accept wires? You already need to power them... \$\endgroup\$ – Bryan Boettcher Jun 6 '17 at 20:40
  • \$\begingroup\$ Also, I think you need to think this through a little more. Suppose you have left-side and right-side sensors that are otherwise identical. How does the controller distinguish them? If the sensors themselves need to be configured, how does the installer accomplish that? \$\endgroup\$ – Dave Tweed Jun 6 '17 at 20:44
  • \$\begingroup\$ @DaveTweed & Bryan - I added an update. Does that help? \$\endgroup\$ – Neil Dey Jun 6 '17 at 21:11
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    \$\begingroup\$ Picking a protocol is going to depend very heavily on the nature and the bandwidth of the data you want to transfer, as well as external constraints such as the power budget. Without any details like these, your question is far too broad to address here. \$\endgroup\$ – Dave Tweed Jun 6 '17 at 21:33
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Others have already commented you need to think about your required bit rate for your application. If you need multi megabit rates your choices may be restricted.
BLE and WiFi are built on 802.11, so within that spec you can pair/bond/secure using the globally unique MAC address. You could consider using BLE modules (NRF52832) or ESP8266 WiFi modules to implement this sort of connectivity.

You could also implement a simpler lower performance network such as ANT/ANT+, here you have a much simpler NetID/Key-pair to define your scope and you implement sensor recognition at the application level. Here you buy a chip implementation such as those from Nordic Semiconductor and have a simple serial interface to the chip/protocol engine.

Below that level of sophistication you could use something like the NRF24l01+, which are ridiculously cheap as a module. This has a simple 40 bit address field and security is a challenge, but they work well. Going beyond six peripherals requires you to roll your own more....but up to six it's essentially all done at the hardware level with minimal software.

One other thing that may interest you is I've used multiple NRF24L01 on a single coax providing both power and signal (think of 10Base2 Ethernet).

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  • \$\begingroup\$ The NRF24L01+ and BLE modules also need much less power than the ESP 8266 and from my experience they also need less effort from the SW implementation side. \$\endgroup\$ – nickagian Jun 7 '17 at 7:20

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