Post 2 - Starter Schematic
Been a little over a week since I last updated. I have been working on drawing up a schematic for how I want to wire up the control system. My plan is to have a little Hoffman enclosure or something similar with some din rail, terminal blocks etc. Just a preliminary wiring diagram/schematic so comments are certainly welcome.
At the moment I have the top section divided by voltages (120VAC, 12VDC, 5VDC and 3.3VDC). I plan on bringing the 120VAC into the enclosure via a cord from a wall outlet, this will drive a 12VDC power supply (Phoenix Contact 2938756 for now...) and the filter, heater, etc. through relays. I had to try and find some low coil power relays for the Arduino to be able to drive via 5VDC without overdrawing on any given pin. I did not want to go through and use transistors or anything to drive the relays like I noticed on some sites. Currently planning on using some TE Connectivity R10-E1Z2-S140 relays for this as they should pull max 20mA from the pin which is acceptable.
Otherwise I drew up the I2C bus, going to need a UART to I2C converter for the flow meter. I realize I could probably just bring this in directly via UART to the Arduino, but for now I am going to try and do all communication via I2C. Going to try and use a NXP SC16IS741IPW,118.
Another note, I did some napkin calcs. I think all should be fine feeding the pump, heater, etc. from the one wall plug on my 20-40 gallon tank. Similar to a power strip but via terminal blocks. Any bigger than this and I might get a little nervous and would need to do some more in depth calculations. I plan on doing this, just haven't yet.
See attached for the PDF! When I am finished I will have this available in .dxf for whoever would like it in CAD. I am currently using QCad which is a nice setup, close enough to AutoCAD to pick up quickly.
Have a good one!