Wiring a float switch inline on 5v pump? (No relay)

Shon

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I came across this:

There are many 3-5v water pumps and float switches found for dirt cheap. Looking at the pump in the link above and knowing most float switches are low voltage dc, can it work? Just splice the wire inline, no relay needed.

Example pump (4.5v, .18a, .91w):


Example float switch (Max Contact 10W, Max Carry Current 1.0A):


I know it's all cheap Chinese made, but 5 diy pumps for 20$... Compared to the 65$ for 1.. Always nice to have backups.. especially with cheap stuff..
 

Jamie814

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They would probably work at least for a while. The problem is when the switch fails it will most likely be in the closed "ON" position as the contacts will "weld shut." Running any kind of load through those switches isn't really a good idea. There best used for just a signal to tell something to turn on.
 
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Shon

Shon

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There best used for just a signal to tell something to turn on.
Was thinking of ATO use, actually. So it'll work but probably use better grade switches..

Trying to piece together a USB powered live food system. Brine shrimp, growing bbs to adulthood.
 

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I came across this:

There are many 3-5v water pumps and float switches found for dirt cheap. Looking at the pump in the link above and knowing most float switches are low voltage dc, can it work? Just splice the wire inline, no relay needed.

Example pump (4.5v, .18a, .91w):


Example float switch (Max Contact 10W, Max Carry Current 1.0A):


I know it's all cheap Chinese made, but 5 diy pumps for 20$... Compared to the 65$ for 1.. Always nice to have backups.. especially with cheap stuff..



Without question it will work! I've done my fair share of float switch DIY's and all of the micro float switches I've built run off 12 V DC....so 3-5 volts, no problem. Other than some crazy Triac (drops AC voltage) setup I once had, I've exclusively used relays to run 120 Volt stuff. That all said, a couple suggestions. Micro float switches will fail. To greatly reduce the chances of some catastrophy, use two, and slightly offset, and wire in series. So when the primary switch fails, the second one will save you. Here's the one I use for my skimmate container:

1701540713573.png


The other issue is that these inexpensive micro switches are truly not waterproof where the wires come out of the top. If your build requires the switch to be submerged, or spend some time under water, I'd recommend mounting in CPVC pipe with an endcap that's been drilled and tapped...if I remember correctly, M8 with a 1.0 pitch. Here's two examples, again, doubled up and wired in series:

1701541042934.png


Best of luck and let us know how it turns out.
 
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Shon

Shon

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use two, and slightly offset, and wire in series.
Ok, will do. I assume wired inline on the black/ground wire?

On route.. probably won't be here till New Years..

Decided on a diaphragm water pump: (5v, .3a)

M10 thread aquarium float switches: (1a working current)
 

redfishbluefish

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Ok, will do. I assume wired inline on the black/ground wire?

.......

Not quite. Every float switch I've ever purchased had two of the same colored wires coming out of them. You simply want to take one of the wires and attached to a second float switch wire....in series. The majority of failures of float switches are them being "stuck" in the ON position. Here's an example of the float switches in series. Note this diagram was for my skimmer pump with the float switches in a skimmate container. So disregard the outlet and relay.

1701614108126.png



For your application, the relay would be your mini pump that's wired to the voltage supply and float switches. The small little trapezoid shapes are wire nuts. Hope this helps.
 

redfishbluefish

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I just double checked the threads on my float switches and found that they are 8 mm with a 1.25 pitch (not 1.0 as I stated above).

Float Switch Threads.jpg


What's important, if you have metric taps, is to use the correct one for your application. Now I realize I'm the wierd'o having metric taps and dies. If you don't have them, the other option is to drill a hole that will fit the float switch and now use an o-ring on the outside and a nut on the inside. Many float switches I've purchase came with both the o-rings and nuts. Do this before you glue the end cap to the pipe.
 
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your mini pump that's wired to the voltage supply and float switches.
I understand. I was referring to the voltage supply, in my case, a 2 wire USB. I was taught to remove the negative on a car battery first. I know that a boat battery switch is also wired to the negative.

So I assume the floats should also be wired to the black/-?

The current idea in my head looks like this.

IMG_20231203_135210414.jpg

I have a few 5.5/2.1 jack assemblies laying around.. also triangle for wire nut ;)

I realize I'm the wierd'o having metric taps and dies.
That's not weird at all if you're using them. I have and use a sae/metric set myself. What is weird is buying a specialty tool to use once and banish to the back of a tool drawer for eternity.. like that ridiculously priced GM oil sensor socket..
 
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Pump came in a week early. Still waiting on floats..

It's so tiny!
IMG_20231213_182347391.jpg
And common aquarium air hose fits it.

...

Also came across:

I feel stupid to not think of putting the pump in the box. So I'll definitely borrow that idea.
 

redfishbluefish

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You can buy project boxes, but if you are handy enough to make a cover, use inexpensive electrical boxes (with the tabs cut off). You can see how I used them in THIS THREAD where I DIY'ed a mini pump......exactly what you're doing.
 
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You can buy project boxes, but if you are handy enough to make a cover, use inexpensive electrical boxes (with the tabs cut off). You can see how I used them in THIS THREAD where I DIY'ed a mini pump......exactly what you're doing.
Don't know how I missed seeing that. I googled variations of "reef dc no relay ATO", maybe it's buried somewhere in the search. But yeah, very much the same diy project.

When I do the build post, I'll quote it and post on your thread since both threads are relevant with the other. Also will do so when I do the brine shrimp build.

Currently hacking up my old surge bucket to reuse, drawing up a simple stand while waiting on the last piece of the physical portion of the build, epoxy coated magnets.


IMG_20231214_044037041.jpg
Just missing floats for the power portion, I have 2 dual USB 3.0 outlets to power:
Submersible pump
Air pump
Led
ATO
 
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Shon

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Still waiting on floats switches.. expected by Jan7.. soon..

Thought about how to connect wires to the little contacts. Soldering I suppose. I don't think I ever did electrical soldering before, only copper pipes.. I'm used to crimps, wire nuts and lever connectors.

I have some soldering stuff that I inherited with my dad's tools. This says acid flux? That says plasticizers? Err.. Okay, this one says rosin for electrical..

IMG_20231222_095104125_HDR.jpg

Then I watched a few YouTube videos. One RC motor looked to be the easiest method. I used some wire from a broken buzzer, stripped, twisted and fed through the small hole and twisted it back together. Used a drop of solder to secure the braid.. and then spent almost an hour pulling down boxes and buckets looking for my small tackle box of spade connectors, heat shrink and liquid electrical tape.. cannot find it.. so that's on hold for the moment.

IMG_20231223_094240150_HDR.jpg

Some change in plans.. I'm going to use this ATO on the 10g aio quarantine and use the 4-6v dosing head for the brine shrimp. Since for the shrimp it's more of a feeder. I have a spare USB outlet and a 12-48v dc timer somewhere to help automate the doser.

I'll just add the USB doser as a +1 to this.
 
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Shon

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Just so happened to look at a piece of 3/4 PVC fitting and the little pump friction fit well, so I'm thinking to use a tee as the holder with pump on bottom with a dab of glue, float connection on the 90 and USB sticking out the top..
 
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Shon

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Ordered a 5v led dimmer to see if it'll work with the doser. Still can't find my heat shrink, so I'll be buying a roll this weekend.
IMG_20240221_091437881.jpg
IMG_20240221_091445344.jpg
IMG_20240221_091551619.jpg
Probably add some 3/4 pipe and coupler to extend and hide the wago.
IMG_20240221_092229754.jpg
Need heat shrink to contain this wire mess.. went with a double float switch. Most likely will cut a square of PVC board and attach float to it for the aio tank. Used a 3x3 wago, tied one set to center and used the outsides for the -/+
IMG_20240222_073250958.jpg
And the "dumb doser", waiting on USB dimmer to see if it can be dialed down or not.
IMG_20240222_073405110.jpg

Hope I can test this soon.. Hopefully can also get some of my 40b stand work done and/or the brine shrimp tank this weekend.
 

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