Mac connection for data logging - WiFi or Bluetooth

I am new to Arduino. I am looking to create a data logger for our solar heating with 5 or 6 thermistor inputs. I want to capture values every minute and send data to my Macbook. However I don't want to leave the laptop connected to the Arduino board (a Leonardo) all the time with the serial cable and there is no wired ethernet close to the service cupboard where the Arduino needs to sit.

So I am thinking of using either WiFi or bluetooth to connect with the laptop. Does anyone have view on which is easiest and/or cheapest for a relative novice? I envisage storing the logged values on the Arduino (for say up to a day) with a process periodically running on the laptop to upload the latest data. I guess I might need an SD card on the Arduino to hold sufficient data - which leads me to think of a 3rd alternative which would be to periodically (say once a week) move the SD card to the laptop to manually move the data.

I would be grateful for any suggestions.


The Leonardo differs only in detail from the common or garden varieties of Arduino, and everything you suggest is doable. For reasons I don't understand, a wifi shield will cost more than the rest of your Arduino kit combined, and more than ten time as much as a bluetooth module. But I guess it can be your last choice anyway.

SD card modules come included on ethernet and display shields.

The files and comms are universal and the Macbook should be just as servicable as a computer. I use a cheapo JY-MCU bluetooth and a freebie terminal RealTerm for real-time datalogging. There is bound to be a Mac equivalent of RealTerm.

Even with time and date stamping, a 2G card would hold about a year of data, so you might not need to consider any communication.

Logging to SD card is a good way to go if you don't need live connection.

For wireless, I've had good luck with bluetooth for data logging and control.


Logging to SD card is a good way to go if you don't need live connection.

And a really good idea even if you do use a live connection. Once you have the initialisation sorted, SD is the reliable backup....

Thanks everyone - bluetooth with an SD card as back up it its then! :slight_smile: