Strain Gauge

I'm a college student on a team that is building a BalloonSat, and we want to use strain gauges for our experiment. We will be testing the strain induced by the near space environment on a small piece of 3d printing plastic using an Arduino Uno, one gauge on the x-axis, and another on the y-axis. I've done some research already and know I'll need to use a wheatstone bridge circuit for the gauges, and a micro volt amplifier to make the small changes in resistance readable. How should I go about choosing gauges and a microvolt amplifier?

Thanks for your help.

The INA125 can be used for these situations. If you use a I2C chip with OpAmp combined with ADC (12-bit or 16-bit) you will have a higher resolution.

Just to clarify. Will the INA125 be used in conjunction with the I2C chip with OpAmp and an ADC, or are they two separate options? Thanks.

Even better, use an AD1231 ADS1231. It is designed for use with bridge-type sensors, and combines an EMI filter, instrumentation amplifier, and 24-bit ADC in a single chip.

brett_bender: Just to clarify. Will the INA125 be used in conjunction with the I2C chip with OpAmp and an ADC, or are they two separate options? Thanks.

INA125 is an instrumentation amp. It has no ADC so you would need to use a separate ADC or settle for the ATMega's 10bits.

dc42: Even better, use an AD1231...

dc42 meant the AD[u]S[/u]1231.

The INA125 is an accurate opamp that runs at 5V. It can be used with sensors and the output is connected to the Arduino analog input (which is 10-bits ADC).

For a strain gauge, the 10-bits is probably not enough. The ADS1231 is so much better.