I need to monitor approximately 25 sensors, none of which is greater than 80m from the monitoring device. The monitoring device will be a single board computer, e.g. beaglebone black, (yet to be decided).
I will be monitoring conditions such as temperature, lux, etc. It will be sufficient to take one sensor reading per minute, (i.e. 25 int total per minute). Because of the variable distance, I do not want to monitor potential noisy and attenuated analog sensor signals. I2C/ SPI are not suited for long distance so this leaves protocols such as CAN, RS485 or Onewire.
I am looking for a protocol that is support by CE marked sensors that can be plugged directly into the SBC. I don't want to have to build and certify each sensor we devise. For example, I could easily build a CAN sensor board but it would cost thousands to run such a sensor through compliance testing. If I negate compliance testing and the building burns down I will be at fault.
I have seen elsewhere a recommendation for CAN for use with wired sensor networks but I cannot find suitable sensors for sale.
So, any ideas for a communications protocol for wired sensors that has industry support?