Peter, Old_Grey and others -
Thanks again for all the help with the two boards I have been working on. I think I am ready to order, and will be using Fritzing. The seamless process is worth the time in shipping. I have looked at the image files that they create for silk screen, drill holes and copper top and bottom traces. It seems that all holes are plated through … as I would want.
Final thoughts about the additions I have made, and a question about using mini contactors.
For background, the boards are for remote monitoring of an Aquaponics project. The remote sensors will be attached to the “stereo” plugs and may have 20 feet or so of 26 ga. 3 conductor stranded wire to put them in place. I have also added a second power jack to monitor the “native” power in the building and look for a power outage. The main power jack for the electronics will be plugged into a UPS to maintain internet connectivity.
I chose to use two mini contactors (Omron G5V-1) … one to sense the power failure by “releasing” a set of contacts which are normally held closed when power across the coil is present. I have added a resistor to the 5VDC power source because the coil amperage rating is 30ma and the “wall wart” power supply by default is 2000ma … and I added a second resister to drop the 5 VDC to 3 VDC so I would not overpower the digital input pin (D8). Have not calculated the size resistor needed
, but I think using Ohms law, I can figure that out (hopefully).
The second mini contactor is used to sound a buzzer … again when some condition exists that would need notification. I have used D5 as the pin which I will set “high” to act as the trigger to energize the coil which powers the buzzer. I feel I can use this to sound the buzzer when any “digital read” condition is out of bounds. I felt that I should add a “pull down” resister to that pin (or perhaps in the code I could set that option).
I do not have a lot of experience with the need for diodes or capacitors and thank you all for you help and patience.
Attached are the Fritzing files as they exist now.