We decided to start the build process with the power control box. Each of the boards are mounted in place using 4-40 countersink screws with a small washer, nylon spacer, and nut (all of which were purchased at Lowes). Using a countersink drill bit allows for the face of the box to remain flat, and that will be essential when a graphic is applied to it later on. I didn't use any fancy method for measuring the best position to place the boards. I simply put them where I thought it would be best and marked the hole positions prior to drilling. The relay board is slightly off center to allow for additional cables. I then removed all of the old cables from the surge protector circuit and soldered new ones to accommodate the required lengths. The on/off switch had to be taken off the board to be moved to another location in the box.
July 3, 2014 UpdateFirst and foremost we need to see what this analog pH sensor can do. We ended up getting this sensor for approximately $30.00 from robotmesh.com; however, we need to make sure that it is going to be accurate enough to use in our design. Our initial impressions right out of the box are very positive. I was able to get a test up and running in under a minute using the provided Arduino sketch and a few wires. The sense wire (blue) was connected to the Analog Pin 0 and the Ground (black) and Positive (red) wires were connected to there appropriate places on the Arduino. After uploading the sketch, I was taking measurements every 800 milliseconds and outputting the reading to a serial monitor window.