This project demonstrates how to build a simple module to read analog sensor and send the data to PC using USB connection. The project uses ATmega48 as main processor and USB FTDI serial-to-usb cable. Simply put header pins on your device which you can plug into providing the microcontroller-computer link. No need for soldering surface-mount FTDI chips which gets expensive for large scale project.
This 5-channel real-time USB analog sensor can be used for a slew of electrophysiological experiments, but you can expand it for inexpensive multichannel digital oscilloscope.
For more detail: 5 Channel USB Analog Sensor with AVR using ATmega48 Microcontroller