diy auto top off
- Thread starter illnino
- Start date
Stile2
New member
I think about 1/2", which is less than I thought.
So as I was also thinking about that problem. I found what is called a Dual Pole, Dual Throw, Dual Coil, Latching Relay. That is a relay that must be turned on and turn off with power on opposite coils.
The purpose of this relay is so I can have two float switches about 2" apart (vertically) and the lower switch turns on the water, and the top switch turns off the water.
I am drawing up a schematic now and will post in a day or so.
Keith
So as I was also thinking about that problem. I found what is called a Dual Pole, Dual Throw, Dual Coil, Latching Relay. That is a relay that must be turned on and turn off with power on opposite coils.
The purpose of this relay is so I can have two float switches about 2" apart (vertically) and the lower switch turns on the water, and the top switch turns off the water.
I am drawing up a schematic now and will post in a day or so.
Keith
tekknoschtev
New member
Stile2 said:
Maybe I'm missing something but isn't this sort of defeating at least one part of the purpose of an auto top off - to keep levels more stable. I've never had an auto top off, but am in the works for building one, and I would thing 1/2" variance would be much more prefered than 2", especially as far as "shock" goes to the tank - 1/2" of freshwater is much less added to the tank - albiet more often - than 2".
Stile2
New member
Prugs,
I know that there are LED Liquid Level Senors, all plastic. With my new schematic and two of those you could position them as close together as you wanted. At lest it is one solution.
Tek,
I think it depends on how big your return section is. Say that we use just the 1/2" float switch we would need a return section that is 10"x15" to have a 0.3 gallon difference between low level and high level. But if I have a 2" difference then my return section can be only 4.5"x7" also 0.3 gallon.
So all I am trying to do is save valuable sump real estate.
Ben,
The web site is relay
Part number 850-5073 and is $14.14
Here is my lasest schematic, a whole new design. The lowest float switch turns on the water, the middle float switch turns off the water, and the top float switch is the fail safe to turn off the system.
I will post pics as I build and install, which may take a while. I need to build the stand next.
Keith
I know that there are LED Liquid Level Senors, all plastic. With my new schematic and two of those you could position them as close together as you wanted. At lest it is one solution.
Tek,
I think it depends on how big your return section is. Say that we use just the 1/2" float switch we would need a return section that is 10"x15" to have a 0.3 gallon difference between low level and high level. But if I have a 2" difference then my return section can be only 4.5"x7" also 0.3 gallon.
So all I am trying to do is save valuable sump real estate.
Ben,
The web site is relay
Part number 850-5073 and is $14.14
Here is my lasest schematic, a whole new design. The lowest float switch turns on the water, the middle float switch turns off the water, and the top float switch is the fail safe to turn off the system.
I will post pics as I build and install, which may take a while. I need to build the stand next.
Keith
tekknoschtev
New member
So is it just preventing high freqency switching of the pump? My area is somewhere like 9x12 or 11x12, if I could redesign it to be smaller, I'd still only want 1/2" variance. More stability as far as the entire system goes... correct? Unless its to prevent the on off cycle of the pump, I dont see the need to complicate it. Though I do like the idea of having the dpdt latching relay, seems to be a bit more of control.
Stile2: nice work on the drawing. 
Tekknoschtev: the purpose of the relay is exactly for keeping the pump running for a little bit of time. Otherwise the circuit will quickly switch on and off (especially if there are any waves in your tank), which will burn out the pump / float / etc. He is using a momentary push toggle relay though instead of a latching. Interesting way to accomplish the same goal.
Tekknoschtev: the purpose of the relay is exactly for keeping the pump running for a little bit of time. Otherwise the circuit will quickly switch on and off (especially if there are any waves in your tank), which will burn out the pump / float / etc. He is using a momentary push toggle relay though instead of a latching. Interesting way to accomplish the same goal.
prugs
Moving Out
http://www.reefcentral.com/forums/showthread.php?s=&threadid=307636&highlight=optical+sensor
Found this thread on optical sensors. For a small tank without a sump, these should be the ticket.
Found this thread on optical sensors. For a small tank without a sump, these should be the ticket.
PetPirate
Premium Member
Are you sure your transformer is "DC out"? Transformers are AC components. You may need to rectify the signal with a diode bridge and smooth it with a cap. Even if it already does these steps for you (i.e. a wall wart), it might be a nice idea to put a smoothing cap in there anyway.
Although it's not that critical for this circuit, if it's a wall wart, check it for regulation under a light load.
EDIT: Also, fuses (on both sides of the transformer) are never a bad idea.
Although it's not that critical for this circuit, if it's a wall wart, check it for regulation under a light load.
EDIT: Also, fuses (on both sides of the transformer) are never a bad idea.
Stile2:
I just ran some numbers on your LED's for what the current limiting resistor values should be. For the yellow LED, it should be 270 ohms. The green LED should be 330 ohms. The red LED should be 560 ohms.
Blazer88:
I (amps) = V (volts) / R (resistance)
To calculate for I, we need to know the total resistance of the circuit. Worse case is you have turn on float closed, which gives 3 paths for the electricity to flow. We know the V = 12 volts, so we need to solve for the total resistance of the circuit.
1 / Total R = (1 / R1) + (1 / R2) + (1 / R3)
R1 = Yellow LED + 270 ohm resistor = 270 ohms (LED is near nothing)
R2 = Green LED + 330 ohm resistor = 330 ohms (LED is near nothing)
R3 = Relay = 88 ohms
So:
1 / R total = (1/270) + (1/330) + (1/88)
R total = 1 / ( (1/270) + (1/330) + (1/88) )
R total = 55 ohms
So going back to the original:
I (amps) = V (volts) / R (resistance)
I = 12 / 55
I = 0.22 amps
So there you have it... minimum required amps from the 12VDC adapter is 0.22 amps, although it is smarter to get one rater higher than that. I would go with a 0.4 or better if you have it
I just ran some numbers on your LED's for what the current limiting resistor values should be. For the yellow LED, it should be 270 ohms. The green LED should be 330 ohms. The red LED should be 560 ohms.
Blazer88:
I (amps) = V (volts) / R (resistance)
To calculate for I, we need to know the total resistance of the circuit. Worse case is you have turn on float closed, which gives 3 paths for the electricity to flow. We know the V = 12 volts, so we need to solve for the total resistance of the circuit.
1 / Total R = (1 / R1) + (1 / R2) + (1 / R3)
R1 = Yellow LED + 270 ohm resistor = 270 ohms (LED is near nothing)
R2 = Green LED + 330 ohm resistor = 330 ohms (LED is near nothing)
R3 = Relay = 88 ohms
So:
1 / R total = (1/270) + (1/330) + (1/88)
R total = 1 / ( (1/270) + (1/330) + (1/88) )
R total = 55 ohms
So going back to the original:
I (amps) = V (volts) / R (resistance)
I = 12 / 55
I = 0.22 amps
So there you have it... minimum required amps from the 12VDC adapter is 0.22 amps, although it is smarter to get one rater higher than that. I would go with a 0.4 or better if you have it
Stile2
New member
Jhong,
Sorry about that, that is just my lack of electrionic know how showing. I don't really mean it is a transformer, it is a 120v ac to 12v dc adaptor from an old set of computer speakers.
And I fairly confident that a cell phone charger that was 12 v would work.
Reef55,
Thanks for running the numbers for me. Again my lack of knowledge showing. What will happen if I just use the 470 ohm on all three LEDs.
Thanks
Keith
Sorry about that, that is just my lack of electrionic know how showing. I don't really mean it is a transformer, it is a 120v ac to 12v dc adaptor from an old set of computer speakers.
And I fairly confident that a cell phone charger that was 12 v would work.
Reef55,
Thanks for running the numbers for me. Again my lack of knowledge showing. What will happen if I just use the 470 ohm on all three LEDs.
Thanks
Keith
Blazer88
Premium Member
That's for the nice demonstration of ohms law, I didn't feel like adding it up I'm going to order the floats and dig around for that charger. Does that relay you have linked need to be the one used for this to work? I'm going to build everything into a nice box and mount the LED's. Should look nice and most importantly, functional.
I'm going to order the floats and dig around for that charger. Does that relay you have linked need to be the one used for this to work? I'm going to build everything into a nice box and mount the LED's. Should look nice and most importantly, functional.Stile2:
LED's have three things that are very important for them to operate correctly... 1, their polarity is wired correctly. 2, they are supplied the correct voltage. 3, and more importantly than 2, they are supplied the currect current. The resistors are there to limit current and drop voltage. If an incorrect value is used, the LED will either be very dim, or worse it will quickly burn up because too much current is being passed through it. In your case, the LED's will be very dim.
The DPDT relay is important in that it is momentary dual coil, also sometimes called a latching relay.
LED's have three things that are very important for them to operate correctly... 1, their polarity is wired correctly. 2, they are supplied the correct voltage. 3, and more importantly than 2, they are supplied the currect current. The resistors are there to limit current and drop voltage. If an incorrect value is used, the LED will either be very dim, or worse it will quickly burn up because too much current is being passed through it. In your case, the LED's will be very dim.
The DPDT relay is important in that it is momentary dual coil, also sometimes called a latching relay.
melev
Well-known member
Okay, let me chime in. Using a relay is safer. I'm sure somewhere in page 2 to 5, it was mentioned, but to sum it up briefly, the relay will run the float switch as 12v instead of 110v. Then when the switch indicates that water is needed, the relay allows 110v to go to the outlet.
I just purchased an AquaLifter from PremiumAquatics for $10.25. It is a small pump that looks like an air pump. You can place it on top of your top off container, and it will suck up water via airline tubing and pump it into the tank. It uses 3w of power.
I just purchased an AquaLifter from PremiumAquatics for $10.25. It is a small pump that looks like an air pump. You can place it on top of your top off container, and it will suck up water via airline tubing and pump it into the tank. It uses 3w of power.
