Hi, about the relayboard, i have updatet the post whit some infos.. TheBoard is one of >this< wich has optocouple isolation. But i dont know if i have to use the 3.3V or if i can use the 5V at the VCC because the relays switch on at LOW state. >Here< is the cirquit.
The problem is that Teensy outputs 3.3 at HIGH state not 5V, so there are already 1.7V.
The coils need 5VDC (JD-VCC), wich i can separate from the optocoupler (VCC).