Hi
You can use AD7730 IC from @nalog devices to condition the low level strain signals and interface this chip with spi interface with any micro like as pic ,8051,avr.
I used AD7730 ,and worked nice for me.But I do offer other AD77 members ,always I had problems with them in noisy and industerial environments.
745 SEN
Sensor Instrumentation Design Approach Abstract:
Designing a precision signal conditioning circuit can be tricky if all areas of the design are not taken into consideration. In this class,a precision load-cell will be used as the signal source, with a full scale output of less than 10mV. An instrumentation amplifier consisting of discrete resistors and op-amps will be used as the signal conditioning circuit, and a stand alone 12-bit A/D converter will perform the data acquisition. Filtering and voltage reference tradeoffs will also be discussed. Each student will then program a PIC18F252 using the ICD2 to show a working system, displaying individual results on an LCD display.