You might be able to install an NPN transistor between the reset pin, a digital pin, and ground, such that setting the digital pin high will cause the arduino to reset.
This is not recommend by AVR documentation and should be avoided.This is because using this method it's not granted the reset will ocur because it could be much faster than the avr clean all internal registers and RAM to a know state.
From atmel documentation:
You should not try to:
- Use another pin of the AVR to pull the external RESET line. The pins of the AVR are tristated halfway through the minimum reset time, this releases the RESET line and hence nothing happens.
- Jump to program location 0. Jumping to program location 0 does not clear all the registers and hence you do not have a "clean" reset.