Cheap and basic wireless sensors?

Projects General Guidance
1

Hi,

I'd like to build a system that allows temperature to be monitored at a dozen different locations simultaneously and recorded/logged at a central arduino node via some form of wireless communication.

I'm looking to build a number of battery operated wireless temperature sensors that can communicate across about 20-30meters to a single receiver. I only need one-way communication, and I don't need to send much data. (also, the data will change only very slowly)

I know I could use one of the wiFi arduinos, but to be honest that's overkill for my needs and probably too expensive. I probably need 10-12 sensors, so I really need to keep the costs down, what are my options?

Currently I'm thinking of an arduino pro-mini with a TMP35 temperature probe to gather the temperature (total cost about £10) but then I need some method of transmitting that data back to the central node.

Ideas please!

2

NRF24L01 is kind of the standard for that :slight_smile:

3

This Simple nRF24L01+ Tutorial may be helpful.

For low power consumption you may need to set each "sensor" as a transmitter so it can sleep most of the time. This creates a risk that two sensors wake at the same time and interfere with each other and your programming will need to take account of that. The failure to receive an acknowledgement will be the signal. The first example will be a suitable starting point for this type of system.

If low power consumption is not needed then the sensors can be set as listeners and the master can call each of them in turn. That will avoid any risk of data collisions. The second example (using the ackPayload technique) can be extended so the master can talk to many slaves.

...R

4

thanks guys - looks like just what I need.

cheers