Yesterday, I went to PVIT, an engineering club at my School. WE were working on an arduino robot, and were trying to wire up 2 h bridges to it.They would take 4 pins(1 pwm) each normally, but as our project also was using a GPS module, limit switches, an ultrasonic sensor, and a servo so far, we decided to save pins. We were setting it to go in forward and reverse, for forward, the 4 pins on the h-bridge had to be fed 100(PWM) and for reverse 01(PWM)0. THe pins that would occasionally need pwm would need thier own pins, but the others were as simple as an output and a NOT gate. Not having any IC, I built a NOT gate out of a 2n2222 transistor and 2 resistors according to a diagram I found on http://www.kpsec.freeuk.com/. I tested this with LEDs, and have drawn a diagram of it for next week’s meeting.