I got the PCB, soldered the components, and it worked! Now only one traffic light can be turned on at a time. My goal was to learn the tools for making a custom PCB, now when I have ideas for projects I can design a custom PCB instead of always having to use a breadboard and worry about loose wires.
Demo time...
Here you can see what happens when the Netduino code is cycling through the lights... (off [0], red [1], yellow [2], red+yellow [3], green [4], red+green [5], yellow+green [6], red+yellow+green [7], repeat.) This picture was taken when all three lights were cycled on. In this case, the relay board (not shown because it is under the metal mounting hole has three wires [red, yellow & green] which when sent logic low [0 volts] will turn on the associated light.)
In the picture below instead of the red, yellow and green wires being directly connected, they go into my PCB board (along with power and ground). The PCB board uses 3-input NAND gates to ensure only the light with the highest precedence is illuminated (with red having highest priority and green the lowest.) In this picture, the Netduino is sending logic low for all three lights (just like the above picture) but my circuit is only turning on the red light, it is keeping the yellow and green light off. With the wires going into the PCB the logic is now (off [0], red [1], yellow [2], red [3], green[4], red [5], yellow[6], red [7], repeat.) Two lights never turn on at the same time!
Here is a video of the PCB...
Here is a video of the lights & the board working as designed...
Comments