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tgunn
03/15/2012, 09:05 PM
I'm currently building a nano tank for work, and have another temp tank setup so I can redo my 34g Solana. But these tanks have no ATO units. Rather than buying them I decided to try making them myself.

My basic design concept is a dual float unit, where the bottom float provides the main top off control and the top float acts as a backup to kill the circuit in case of a malfunction of the lower float. The floats switch a 5v DC power source to trigger a power relay which switches a pump on/off.

Supplies (for each unit) (all from DigiKey):
G5LA-1A4 DC5 - Omron SPST 10A NO relay with 5v DC coil - $1.46
You'll need two of EITHER OF THESE ($14.19 each):
LS01-1A66-PA-500W - Meder Normally Open Float Valve - with this type of float valve you can mount the float with the wires out the top and the float hanging below.
or
LS01-1B66-PA-500W - Meder Normally Closed Flaot Valve - I accidentally ordered this type; the circuit is closed when the float is at the end with the wires coming out; so I had to mount them upside down. durr

EPS050100-P5RP - Cheapest 5v switching wall transformer - $8.64
A bunch of PVC parts (elbows, pipe, etc)
A mounting box and wire.

Here's the general idea of how I'm going to mount the float valves:
https://lh6.googleusercontent.com/-9GNuAckruoE/T2KWbNHrRvI/AAAAAAAACQo/_04bCleyWos/s512/Web%2520Albums%2520App%2520Upload%2520-%25202012-03-15%25208%253A24%253A52%2520PM.jpg

I used 1/2" PVC elbows and a 1/2" PVC plug to provide a mounting point for each float. I drilled a small hole in the center of each PVC plug and screwed the float valve in. The float valve has a little rubber seal and a nut to clamp the valve down to make a watertight seal. I mounted each float and then filled each PVC plug with epoxy resin to help ensure water doesn't make its way in.

This is where the project has to stop today though -- my two jars of PVC cement were solidified, and apparently I left the lid off my PVC cleaner and it all evaporated. Lol oopps!

tgunn
03/16/2012, 05:50 AM
Here is a closeup of how I mounted the float valves into the PVC caps:
https://lh5.googleusercontent.com/-4ks-1fZoyEM/T2Mb3MtlclI/AAAAAAAACQ0/shctHX0lKv8/s512/IMAGE_42436C81-99C9-4BE7-900D-11345C9B947B.JPG

Here is the inside, which I filled with 2-part epoxy to help ensure a leak-free seal:
https://lh4.googleusercontent.com/-cj4dfu-86GM/T2Mb57JJqgI/AAAAAAAACQ8/v4rFKyr2fK8/s512/IMAGE_38595732-0C6C-4204-92EE-6E90C61A3EF2.JPG

tgunn
03/17/2012, 07:25 PM
I finally got around to getting some PVC cement; they only had grey -- I prefer clear.

Anyway, heres the two assemblies glued together:
https://lh3.googleusercontent.com/-D2Am8WLPmFE/T2U47C61FRI/AAAAAAAACYg/-aL-oku6qLo/s720/IMAGE_A6F3118B-DC38-4659-8837-C0AF9B024FDD.JPG

Next step: wire up the relays and outlets.

tgunn
03/20/2012, 06:46 AM
I finished wiring up one of the ATO units last night.
The relay and all the wiring were mounted inside a PVC outlet box. In retrospect I should have used a power supply mounted internally to the outlet box. It seems silly that the ATO has two cords :)

https://lh6.googleusercontent.com/-ZEGDKhb3qjM/T2hnnM6dXMI/AAAAAAAACaM/eelyHOkiB5M/s512/IMAGE_56DE6C64-8B10-4923-A147-C69A32896E86.JPG

Here it is mounted in the sump are of my temp 34g tank where the contents of my solana will soon be moved:
https://lh3.googleusercontent.com/-QhZgXLredyw/T2hnjeA9VVI/AAAAAAAACaE/akRjzJqGV_w/s640/IMAGE_5D0CA549-F89D-46C2-8928-7CBE9BE38740.JPG

SchnitzelReef
03/20/2012, 04:44 PM
How much did u spend total? Autotopoff.com sells the same dual kit for like $55. Cool DIY though


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tgunn
03/20/2012, 05:37 PM
How much did u spend total? Autotopoff.com sells the same dual kit for like $55. Cool DIY though


Sent from my iPhone using Tapatalk

Relay: $1.46
Floats: $24.66
Power supply: $8.64
Box: $5
Fittings: $2
--------------
Total: ~$41.76

I didn't do it because it was necessarily cheaper; when you include my time to assemble it was way cheaper to just buy from autotopoff.com. :)

I want to ultimately build up a super-deluxe arduino-based top off unit and thought I'd play around with a standard one first to proof out some of the concepts and try my hand at soldering something.

My end goal is to design a "learning" top off unit which will learn the normal evaporation rate and be able to detect when "abnormal" top off requests are being received. This will act as a sanity-check to the hardware, and also as a means of preventing a leak from causing the salinity to go out of whack or something like that.

jayinh
03/20/2012, 05:56 PM
very cool build. i built one similar and used internal P.S. to activate relays. its very cramped inside the box but all fits and one less external connection. i must admit i do perfer to build from scratch rather than a kit, but in the end the price is usually more.

http://i499.photobucket.com/albums/rr360/jayinh/ato007.jpg

tgunn
03/20/2012, 06:37 PM
very cool build. i built one similar and used internal P.S. to activate relays. its very cramped inside the box but all fits and one less external connection. i must admit i do perfer to build from scratch rather than a kit, but in the end the price is usually more.

http://i499.photobucket.com/albums/rr360/jayinh/ato007.jpg

Nice idea with the double box. I wish I had thought of that. The built-in power supply would be nice. I also like the addition of jacks to plug the floats in.

I managed to find the optical water level sensor the Tunze osmolatar uses. At 55 for that sensor alone I can see why they cost as much as they do

But for me DIY is half the fun. :)

Redman88
06/23/2014, 01:01 AM
Thanks for the idea. Been kicking around one like this in my head for a few weeks