Haq, make no mistake, developing such an instrument is scientific work. You will not succeed very quickly but will have a lot of work to do.

If you want to measure the specific resistance of semi-metals then you should use the "Van der Pauw" method or the "4 peaks" method. Sorry, I don't know the correct translation of the latter method. Such an instrument contains electonics to generate a current and to measure a voltage drop. Afterwards lots of numerical calculations have to be done, which can be the job of a microcontroller very well.

One simple method to measure (or better estimate) the heat conduction properties of a material is by using a rod which is thermally isolated and heated at one side. Then you measure the temperature difference between two separated points along this rod. Fouriers approach is used to calculate the heat conductivity then.

There are many many methods you can use. Which is best suited depends on the actual shape of your samples.

Kai