Remote Controlled Circuit Breaker and Moisture detector

Hello All,

I am doing a project and I am responsible about safety for aquarium light system, I am supposed to have a moisture detector ( Could not find online) that detects if the prototype falls in the water of the aquarium. If it did, the sensor then sends a signals to open up the MAIN power supply which will result in shutting down the whole system including the moisture detector (since I am getting my power from the MAIN power supply) so I guess I will need my own power supply probably. For the circuit breakers, I have a “Latch Relay” dual coil switch (DSP1-L2-DC5V)that has a magnet where it will save the last state it had before tripping so the user can not reset the system by just plugging and unplugging the wire in the outlet. I will also have two mechanical push buttons, one normally open and one normally closed to be able to reset the system manually. I also need Remote Control Circuit Breaker (RCCB), I have searched for RCCB for over a week now and could not find one that has current rating between 60 mA to 250 mA. They all operate with current ratings from 5A to 100A which is away from ideal for my project.

Please, I need help in finding:
1) Moisture Detector
2) Remote Control Circuit Breaker: Current Rating between 60mA and 250 mA


Thank you

1) Moisture detector. That's going to be tough. Unless you use a dew point sensor or roll your own knowing the temperature of the surroundings, the surface temp and the humidity. You could make your own "water alarm". Place flat interdigitated fingers (PC layout) on all 4 sides. Usually you apply AC and detect the resistance change. Or Use a GFCI which is what I would recommend. The "water alarm" would detect it falling in.

2) Not sure of your need for a remote breaker and what you require for a remote breaker. Shunt trip? Voltage? Something that can be done is that you can "crowbar", i.e. short a DC supply with an SCR and trip a regular DC breaker.

I am somewhat lost with your request.

There are maybe a few ways you can look at this.

I don't see you needing a moisture detector or relative humidity detector as rest assured if this device falls into an aquarium the RH and moisture will go to 100% real quick as in dry to real wet.

The first would be to look at a few GFCI (Ground Fault Circuit Interrupt) circuit breaker schematics not to use one but to gain an understanding of how they work and use that concept. That scheme could likely be employed.

Another option might be to employ the use of a comparator circuit. If we can use a photocell to turn a lamp on at darkness using a comparator we can certainly use one to detect a flood. The comparator output could likely toggle a flip flop that either turns a relay on or off.

The sensor can be home brew with a few wires soldered to any conductive foil like copper foil. Years ago I would cut a US one cent penny in half and solder leads to the halves leaving a small gap. If the gap was bridged with water (like aquarium water) the open resistance would drop.

Anyway, those thoughts may help..........

Ron

Well, I am trying to protect my prototype (aquarium light system). I am placing the circuit breaker in the main power supply so when it trips it will open up that power supply and there will be no power for the whole system when it immerses in water. So, I need to directly and quickly open up the power supply before everything is in water!!!

options that I know: Latching Relays or remote controlled circuit breakers RCCB

Note that Latching Relays have a memory element to save the last state it was in and that is a nice feature in this type.

The relay you have chosen is a two coil latching relay (DSP1a-L2-DC5V) manufactured by Panasonic). Pulsing one coil will "latch" the relay and it will remain latched. A 5 volt pulse to the other coil will unlatch the relay. Really matters not that the latching is mechanical or magnetic. The point is when power returns the relay will be in the last state it was in. The relay will only change states when a pulse is applied to either coil. Note relays like this that latch are pulsed on or pulsed off. Constant current is not applied to the coil(s) for either state.

So you design the circuit with a push button on and a push button off but..... the push button off is in parallel with a sensor system that can also trigger the pulse for an off state. Use a "one shot" in parallel with your off push button. The light(s) are powered through the relay.

As to the circuit breaker aspect I don't get where you are going with that? There are circuit breaker types with DC coils embedded where the coil must be energized for the breaker to function but I don't see a need for what you want to do.

Ron