I am a musician experimenting with a sound effect. I need a dpdt switch that continually switches between two effects. I get the sound I like using a dpdt manual switch but I need to have the switch continually move between the two sources. I've read about an "h-Switch" but have been unable to find one that continually switches. I want to be able to adjust the rate of the switch from 2 times per second upto 100 times per second. Is there one for sale or should I build one. Finally, I need it switch to work using a 9 volt battery. Help me Obie Wan. You're my only hope.