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dchild

Auto topoff - relay + float swtich

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Hi, I saw a thread in the sale section saying a float switch would be a great DIY project.  I built one recently for a total cost of <$25 (not including the powerhead).  I wrote it up on nano-reef so I could include pictures.

 

http://www.nano-reef.com/forums/showthread.php?s=&postid=389085

 

The basic idea is that you can get cheap float switches from floatswitches.net but they are only reliable if you run low voltage and current through them (we here have a very low tolerance for float switch failure).  So you need a relay to control the power.  Radio Shack sells a nice little 10A relay, but the coil runs on 12 VDC.  In this thread I built my own power supply at a savings of like $2 over a wall wart but you can substitute the wall wart with no problems.  I believe floatswitches.net has a fixed shipping cost so it's easy to get extras to make this as redundant as you want.

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A few things.

I have a similar setup. I can run up  to over 500W gadget.

A voltage lower than 12V is better in salt water. I run a 9V relay.

 

But here is another option. There is a solid state relay, where the

trigger voltage is like only 3V and can stand 100's of millions of switches

unlike the electro mechanical one.

 

My next one is gonna use that.

 

-krish

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Krish,

What brand and where can you get this setup?

I need to get a couple of topoffs ASAP!

 

Howard

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Here's an relay I use that can handle up to 10 amps! Can probably get a bunch of them fairly cheap if there's demand.

About 5.x1.5x2".  Kinda big, but reliable and screw terminals!

 

124relay.JPG

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I like this idea, and nice relay Doug. I have a couple of 10 amp but they're 110V and there is no way I 'm going to put them near my water.

 

Chris

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Doug.

That looks like a power relay. The mouser catalog shows look alikes that are around $20+.

There are just one too many choices at this point.

 

Relays

------

Omron subminature SIP solid state relay

Input voltage -5v DC

 

Can Control - 100-220VAC load and upto 2Amps.

This would be good enough to run pumps like a mag7 etc.

Cost - $3.85

Mouse part# - 653-G3MB-202PL-DC5

 

This appears to be the cheapest option i guess.

Folks that want to control quite high output like 500W can just add 3 of these in parallel.

 

But what are you going to control?. Btw, this is a Printed circuit board mounted one.

Is pretty easy to rig up.

 

I just control a solenoid. So just one will do for my application.

 

There are other cheaper higher amperage choices like the magnetic relays as well.

 

These should last a long while as well and can go like 10+ Amps and we can similarly

have 2 of these in parallel to run higher wattage.

 

So here are the things one would need.

 

1) Relays 1 or 2 or N

2) AC to DC adapter 6VDC/200mA = $3.99

3) A small PCB - $3 or 4 from rat shack or else where.

4) Some wires.

5) 2 float switches - $14

6) A 3 pin socket and an enclosure from rat shack.

 

-krish

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Hey, I know it's a power relay, but it works...

 

Sorry, work was throwing out multipacks of these, so I got a handful for free. Our price was only about $9 each, but we bought in bulk. I'm sure it would take plenty of simultaneous powerheads on at once to burn one out though. I am also fond of overkill, even if turning on MH's.

 

There you go again krish, being all smart and economical.

 

[ws]

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By the way, while we are talking frugal, our manufacturing facility throws away boxes of extra power switching supplies. 12V 5A range gallore! If anyone needs for switches, fans, etc.., just ask. Not sure about how many of the lower voltage ones they chuck, but I will check.

 

I feel like I'm at a hamfest.

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Hi Doug,

 The 12V can be converted to any voltage up to say 9V by the use of regulator chips.

 

 The regulator chips are available in rat shack and are cheap.

 

 You can get different of these and get anywhere from 2 to 12V.

 

 I would love to jump in and pick a few, but then will have trouble storing stuff.

 

The power relay block you have is pretty cheap for the price.

 

-krish

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Ok I am a troglodite when it comes to this stuff- I would love to attend a DIY party to see it wired together and am totally in agreemnet that we have to have dual float switches, to reduce the chances to near zero of flooding.

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Well here's the wireing diagram I was going to use. It includes 2 floats and a relay. Would this work with this switch.

 

Top off

 

 

I also wanted to setup a couple to turn off the main pump in case of a flood I use overflow boxes and thought I could setup a float in the tanks that would turn off the main pump in case the overflow, lost siphone. This switch would have to be a lacking circuit with a manual reset.

 

Chris

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wow!  this is turning out pretty well.  krish, I agree that the lower the voltage the better, and also that solid state would be ideal.  I think for most of use it wouldn't make a huge difference though, esp for the price difference.  Jameco sells a 10A relay with 12VDC coil for $1.09.  Mechanical life expectancy is 10 million operations.  Electrical expectancy is lower at 100,000 operations but that is at the rated loads (120VAC @ 10A = 1200W) - since we will most likely run far less that, the electrical life expectancy should start to approach the 10 million.

 

For comparison, this guy (http://www.californiareefs.com/home.htm) sells float switches that look like he runs not only 120VAC through the switch, but runs the entire operating current through it!

 

If there is interest in having a "float switch party" we should buy the relays online as a group order since shipping is such a high percentage of order costs with electronics.  Grab a 6-pack and a soldering iron and we're good to go.

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[nana]  [beer2]  [nana]

Lets Do it!!!!

 

Howard

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Here's a tentative parts list from jameco:

 

This is a mini power supply to drive the relay.  It's a 5VDC coil on the relay, so only 5V will run through the float switch.  Relay is rated at 10A for 125VAC.  Transformer supplies 10VAC, the rectifier and cap convert it to DC and the 7805T regulates it down to 5.

 

BRIDGE RECTIFIER 1.5A100V  279515 W10G $0.34

CAP,RADIAL,1000uF,16V,20% $0.16

RELAY, G5LE-1 DC5   $1.49

IC, 7805T  51262 7805T               $0.35

TRANS,POWER, (120VAC - 10VAC, 120mA)   $2.95

 

total cost ~$5.50.  Shipping will double that if we just bought one set, so it's worth it to see if there are a couple interested parties.

 

We will also need boards - RS sells a decent $1.60 protoboard

 

Electrical supplies, if you like the blue plastic box from my link above I think the box, outlet, cord and cover ran about $4-5 from HD

 

and of course float switches, $6 each from floatswitches.net

 

I do not have the space to host anything unfortunately, but I can attend and explain how I did it/teach you how to solder/etc.

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Guys,

My place is a wreck with the remodeling going on, but I would like to host this anytime, Sunday the weekend of the 9Jan?

I have a good amount of space in the basement now, HD is right around the corner for last minute needs.

Interested?

 

Something, I also looking to do, though might aready start before you get here is setting a control panel in my "aquarium filtration room" closet behind my tank. (another discussion later)

 

Game?

Howard

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Sunday 9 Jan works for me.  ctreptow, it looks like that diagram turns on the pump when the lower float switch falls and then doesn't turn it off until the water level reaches the top one.  It does that to provide a buffer so the pump isn't on and off all the time.  However, that introduces some salinity flutuation in your tank.  That also means that despite 2 float switches there is no redundancy.  Also I don't think it's necessary as some powerheads (maxijets) can handle it - if they can work for years as wavemakers they will work for years in this application.

 

Krish - where do you find the $4 6V AC adapters?  That would be easier than building our own power supply and the same price.

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DChild,

What is your real name? Update your profile mystery person  :)

 

Anytime during the day 9th will be good, will have the NFL Playoffs on the tube or if everyone thinks we can get together sooner, the 3rd would be good too, either is fine?

 

I'll let you Electronic Wiz's figure out what is needed, LMK when your ready to order or what you need to pickup?

Tools, I have alot of construction tools, but no soldering irons?

Howard

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You guys looking for power supply or transformers?  I got few Plug In Class 2 transformers available, Input 120VAC and Output 12VAC at 1000mA rate.  LMK if this works or they can be used for the flow switches.

Jacob

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I also got two maybe three DPDT 5AMP 6 to 12 VDC relays available.   And we got wires by the millions and colors.  Again LMK if this will work.

Jacob

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I'm in. And can supply irons, solder. I may have enough of these big relays to just donate, depending on demand (3-24V DC input). Will see if I can get 5V supplies, but if I get the 12's we probably should regulate it (by 7805's or resistor+zener?).

 

Cant we just buy the 5V DC power supply from the shack if we cant get donated, and skip the rectumfriers, craps, etc...

 

Just need to get float switches and relays (again, if not donated)

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I am in - let me know when and where- Looks like your house Howard?

I still say there needs to be redundancy in the shut down- like two float switches, which is what  see as he weakest link.

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IMO,

I'm looking at 2 Topoffs for the redundacy. Back up I think should be mandatory.

 

FOLKS< Would Sunday the 3rd be a better date, Anyone with a problem with that?

 

Can someone start a wish list of supplies that knows what we need:

Just an example:

Description/Source                                Cost    

Topoffs Switches                                  $6.00 www.floatswitches.net

Bridge Rectifier 1.5A100V  279515 W10G   $0.34

CAP,RADIAL,1000uF,16V,20%                  $0.16

RELAY, G5LE-1 DC5                               $1.49

IC, 7805T  51262 7805T                         $0.35

TRANS,POWER, (120VAC - 10VAC, 120mA) $2.95

 

Howard

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If you guys are pressed for space we can do it at my house, I have a huge basement and we can watch football on the big screen too.  LMK  I am open Jan 3 and 9th as well as 10th.  Lee this is a good opportunity for you to come and see my set up.  Also I live between Springfield and McLean kind of in the middle between Lee and Howard.

Jacob

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We can use a wall wart, 9V is $3 at jameco, still ought to regulate down to 5 to minimize voltage inside the tank.  The reason I suggest the other way is for neater presentation.  With the wall wart either you have to have 2 things plugged into the wall (the wart and the power cord) or you have to fit the wart into the enclosure.  It is more soldering but not much - just a rectifer and capacitor (6 wires) - if we are going to regulate the 9V down to 5.

 

We also need to think about how to mount the float switches.  HD sells a pack of 4 plastic clamps for like $3 with which you can clamp the wires to the side of the sump.  In my link in the first post I show how I made one with a homebrew racking cane clip - I can get those for 2 or 3 apeice.

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