Standalone Data Logger Based on AVR Butterfly

The AVR Butterfly is utilized to create a data logger that can be used to monitor temperature, light, battery voltage, and external sensors that can come from digital signals, analog voltages, or a frequency.
The various data logging parameters can be adjusted using the RS232 and joystick as the data logger can be configured via RS232 interface. The flash memory logs and stores the data as a 2-byte binary value while the contents are viewed as graphics. A binary download option was added to allow the data to be read from the device very quickly due to the increased memory size and download times.

There are 4 analog voltages from 0-VCC that are included in the current usable sensors and are accessed on the JTAG port of the Butterfly. The USI port on the Butterfly has been added with a SHT75 sensor along with the onboard temperature, light, and voltage sensors. The standard voltage reader is simply a standard ADC channel with formatted output that is connected to the battery.

The two diodes are used to connect the onboard coin cell and external power input to VCC for redundant power system.

Rest of the project