I have a traffic light that Im looking to control with an arduino. I programmed the arduino to cycle 3 digital pins the amount of time that I want each lamp to stay lit. I picked up a relay board of off ebay to control the AC voltage. The board had 4 channels that include a relay, transistor, and resistor for each channel. The problem is that channels stay engaged while another lights. I have hooked a digital pin straight to the input pin on the relay board and run my AC through the common and NO contacts of the relay. Im a little confused as to why Im having more than one channel engaged at a time. The software is fine. I tried it using LEDS before I hooked up the relay board. Any ideas to get me going?
No schematic...pretty simple board really. If I unhook digital pin 13 all is well with the other pins. I tried another 328 and it is the same thing. Thinking about trying another digital pin.
Welp, figured it out. The relay board has 1 bad transistor and one of the relays on another channel sticks at times. I guess that is the price you pay for some of the cheap junk on Ebay! I only need 3 channels so I might remove the bad relay and sub the other one in.