I want to be able to view the temperature readout of the probes either on my phone or on an LCD screen. I was thinking of using Bluetooth connections…
Would I need to use 2 arduino boards? one for the probes and the second for the LCD Screen.
Would I also need 2 Bluetooth Shields do accomplish this communication?
or should I look into Xbee devices?
I don’t think you have been resolute enough about what you want to do.
A plain-vanilla HC-05 Bluetooth should work well for this provided the range is OK. This is about 10m line of sight. In this event you can get by with one Arduino and one Bluetooth to do the all sensing and the transmitting. That rig can also do local display.
You can send to a phone, in which case no more Arduino is needed. Same applies to PC. If you can get by with three sensors, I use Bluetooth Graphics Terminal, which puts three little graphs onto an Android phone. It is excellent and the main reason for my getting the phone.
If the Bluetooth isn’t up to the job, you might need to consider Xbee or Zigbee. I believe some of that stuff can work as a stand-alone remote sensor, no Arduino needed, but you are likely to then need an Arduiono at the receiving end in order to make sense of it all. In that event, the receiving Arduino could then re-transmit to the phone via blue tooth, so still no LCD required.
Bluetooth is so simple and so cheap you ought to try that first.
The only time you need more than one Arduino or Bluetooth is when you need Arduino<>Arduino communication, which is not likely.