Bluetooth HC-05 Q&A

Brief project description:

Network of liquid intrusion sensors each operated by its own Arduino mini & HC-05's.-(slaves) If liquid is detected at any of the sensor locations, HC-05-slaves sends response to nano/HC-05-(master).

Explanation:

As i understand HC-05's are 1-1. (master-slave). Perhaps it is possible to configure mini so that only one HC-05-slave is communicating with the master-HC-05 at one time to satisfy any 1-1 requirement. For instants, All Mini/HC-05-slaves are in sleeping mode. No link to HC-05-master. If a mini/HC-05-slave detects liquid intrusion it will automatically connect to the master HC-05 to relay message. Then disconnect the link.

Questions: Is it possible for (5) or more Mini/HC-05-slaves to message (1) nano/HC-05-master ?
Is there another way or better way to achieve the same out come ?

thnx
taz

Does it have to be Bluetooth? If not the rf24 radios may be worth a look. One rf24 master can communicate with up to 6 slave rf24 units. A rf24 tutorial by Robin2.

If a mini/HC-05-slave detects liquid intrusion it will automatically connect to the master HC-05 to relay message.

The above is nonsense, but the answers to your questions are yes to both.

You could have a master bluetooth polling several slaves using sequential configuration. The possibility that some might be asleep would be irrelevant.

An NRF24 network, as mentioned above, would surely be a better proposition, as they are designed for that sort of thing. The cost and performance is about the same as bluetooth. The only good reason for using bluetooth would be that you already have them in your hand.

Does it have to be Bluetooth?

Nah. Nano actually has 1 slave HC-05 that communicates with the app. I was using nano as the hub, the app as the command center. I was happy with the penetration and range performance of the HC-05, so considered using them again in the project to relay info to nano. Range 15-20 meters indoor.

Thnx for the link & suggestion.

You could have a master bluetooth polling several slaves using sequential configuration. The possibility that some might be asleep would be irrelevant.

The potential issue I see is power efficiency on both ends of the link. Sleep is very relevant in terms of power consumption.

The above is nonsense, but the answers to your questions are yes to both.

The method I was suggesting was to cut power to the HC-05 when not in use by mini. A triggering event on mini powers up the HC-05 slave to auto connect and relay message 3x times to HC-05-Master nano. Then power off link.

True, the NRF24 is probably the best option overall. With the added benefit of multiple channels allowing me to identify which sensor responded.

thnx for the suggestions.

taz

The above is nonsense, but the answers to your questions are yes to both.

The method I was suggesting was to cut power to the HC-05 when not in use by mini. A triggering event on mini powers up the HC-05 slave to auto connect and relay message 3x times to HC-05-Master nano. Then power off link.

What you are saying is still nonsense but, since you propose controlling the power to the various HC-05s, I guess you can do what you propose by having several masters calling one slave. HC-05 is not famous for low power consumption, so I believe you may still be better off with NRF24, which are.