The Micro-ADXL335 is a small, thin, low power, complete 3-axis accelerometer with signal conditioned voltage outputs compatible to ATmega328. It can measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion, shock or vibration.
The Load Cell Amplifier Micro-HX711 is a module that easily read load cells to measure weight. By connecting it to microcontroller (ATmega328) you will be able to read the changes in the resistance of the load cell, and you’ll be able to get very accurate weight measurements.