I bought the sensors at Digi-Key (digikey.com) for a little over $5 ea.. Digi-Key is not the best (least expensive) place to buy electronics but it was the only place I could find them, which is usually the only reason I buy things from them.
As for the software. I wrote the software for the 8051 microcontroller (in 8051 assembly) for this project myself. It only reads the sensors, converts them to ASCII text messages and sends these messages and some LCD control messages to the serial LCD display to show the results. There is no reason these results couldn't be sent to the PC through the serial port instead (and it would also give you something to use the serial ports for
) and displayed in a pop up window say using Visual Basic. I have not written any software to do this. MBM5 looks for known sensor IC's on the SMBus (a system maintanance bus that uses a slight variation of the I2C bus) . SMbus headers have been on nearly all motherboards for several years now. I don't know if the newest generation of motherboards intend to include it or not. Since my setup is not common and does not use the SMbus, MBM5 would probably not see it. Even if the hardware was changed to use the SMbus, MBM5 would probably not recognize it. And since MBM is no longer being maintained, and the source code is not being released, there is no way to add it.
I have also designed and written the software for a variation that can read eight temperature sensors and sense eight fan tach outputs and output ALL of them once every second. It could also control (on/off) up to eight fans. The fan tach outputs require more math than the 8051 can handle in one second to convert them to RPMs, so this would have to be done by the PC. I have considered using serial, USB, and SMbus to get this information to the PC where it would be displayed on the monitor instead of an LCD display much like MBM5. The original plan was to market it, but this has gotten nowhere.