As far as mounting and housing it I will breadboard it first to make sure everything is working properly. Then I will move it to a small pcb. I have a bunch of small project boards around that should work. I will choose an enclosure once I have a chance to size everything up. Did you have any specific suggestions here?
Now I have to take another look at that sensor and get it ordered.
In the means of what I had in mind. I had a PCB made for mine and is mounted in a single gange electrical box mounted to the wall behind my tank.
The lead time is worse case I believe I got mine in about a week.
The ebay item I would ask a few questions;
1st. Why is the bid starting at $14 when the manufacturers web site has the same part fo $95 (http://www.dwyer-inst.com/Products/Product.cfm?Group_ID=16&sPageName=Ordering).
2nd. Neither the manufacture or ebay state weather the output is high in air or in water. If it is high in water than the design will have to be modified.
The choice is yours.
[side note]
here is what I was thinking for the final board, the SSR would be mounted elsewhere's.
That PCB is pro! What does something like that cost and how long does it take to get done?
I will call the manufacturer on the sensor tomorrow and check the lead time. I don't want to take a chance so I think I will stick with your suggestions and go with the one you linked to. I hope this anemone doesn't have babies again!
I use batch PCB it is about a month for final product $10 setup fee and $13.30 for the board (so $23.30 would get you 2 boards). the link to the board if you want it is here.
That board is designed to fit nicely into this, and this cover drills nicely for the switch.
I think I am going to hold off on the board. It would definitely make the project look nicer but I really don't want to wait a month for it. Also the added cost is a consideration. I have had good luck in the past just using the generic project boards.
For future reference how do you make the custom PCB? Is there a program that you can enter a schematic and then it spits out the design? I love the look I just don't have the know how.
I use Eagle. It takes some getting use to but it works. The home page is here if you want to check into it. Also I attached the Eagle files for this project if you want to check them out as well.
Pam, that is an interesting idea. I just have a feeling by the time the aspirin dissolved there would be water on my floor...again. I need an instant solution.
Dustin, what is the cost like on those? I am unlikely to use them for this project since I have already ordered other parts but I am always looking for inspiration for future projects!
I think these units sell for $150 or so. However, I think the group could work out a DIY solution. As I understand their function, the 2 metal rods have a very small AC potential across them. When both are immersed in a conductive solution, current flows, triggering some internal logic, relay, etc. These work well for precision level control because you can make the leads different lengths. This allows you to (for a high-level alarm) to set the longer leg into the water and adjust the shorter leg to the exact cutoff point that you want. They make these units with leads up to 48" long (in stock models) and they can custom make units with leads however long you need.
They make a 3 legged model, which is the one I use at work most often. I can set 1 leg to be very long and 1 leg to be slightly shorter. This serves as a low-level alarm. Then I set the last leg to be very short, giving me a high-level alarm. It is very simple and more elegant than float switches.
I'm pretty committed to the design that has been laid out at this point. I was originally thinking about going the way you mentioned, Ken, but I couldn't find a simple circuit. I was also worried about probe corrosion. I understand that AC current prevents corrosion due to (what I understand to be) electroplating, but I am worried due to the fact that they will be in very close proximity to salt water. The salt water obviously corrodes stuff badly, electrical or not. The IR sensor is sealed tight and the rest of the circuit can be safely away from the water.
I appreciate everyones input for this. Keep those suggestions coming!
Kyroguy,
I'm an electroplating chemist, and while I normally work in the DC world, I've never had any of my purchased sensors fail due to corrosion. Then again, my probes are either stainless steel or titanium . . . ;-)
To add to Dustin's post, I used ER316L stainless steel TIG welder filler rod for my electrodes. 316 has "excellect" corrosion resistance and is used in saltwater environments.
Then again, if you have sealed sensors, all the better.