liudr:
Does the relay control have a ground that goes from arduino to breadboard then to relay control? Just checking.
The 5V relay control is currently powered by the same 5V/GND from the Arduino to the LCD & backlight. Is this correct?
About half an hour ago, the garbage character problem showed up again. It happened when I tried to turn on and off 17 solenoids (one by one in consecutive order with one second in between). But it did not happen again when I repeated the same steps. So the problem is evasive. BTW, I do not have the 10uF cap between Vcc and GND yet as I still need to get the part from the local store.