Look into the shift register (74hc595 for instance). Using 2 or 3 pins to control as many solenoids as you want in any order with SPI or bit banging (shiftOut()). Another route is the I2C port expander (2 pins ,A4 and A5 on Uno).
Look into the shift register (74hc595 for instance). Using 2 or 3 pins to control as many solenoids as you want in any order with SPI or bit banging (shiftOut()). Another route is the I2C port expander (2 pins ,A4 and A5 on Uno).