Tamperproof sink

[pusur44017]

Hello all.
I'm hoping you'll find this backstory somewhat amusing, and I'm including it for the purpose of its entertainment quality and to see if anyone has any better ideas.

For context, please view this http://3.bp.blogspot.com/-ZHweCp1Yfr8/Tn-CTr0P6_I/AAAAAAAAB80/bixPQ7-yarM/s1600/nytt+bad21.jpg

Anyone having cats will understand the obvious attraction this marvel has to felines. Now I have two cats interested in it. Cat one will balance at the edge of the sink, yelling loudly to DEMAND having the water flow, cat two... not so much. Cat two will happily turn on the sink with her paw, and she doesn't really care about the amount of flow or temperature...

Besides the obvious waste, it could be dangerous with the hot water.

Closing the door to the bathroom isn't an option as the cats will claw at the door, it's a very popular spot because of the underfloor heating.

Using a rubber band or some other sort of obstruction works, but we forget to put it back on after using the sink and she'll chew through duct tape when we're on holiday. (It's like a time pencil: you can see how far she is from getting through)

I want to do solve this by using some water valve solenoids, a li-ion battery, switching regulator and some sort of timed button.
I want to be able to press a button, which turns on the NC solenoids for say 5 minutes. I'm having trouble finding the timed button. I also want it to be as power efficient as possible.

-pusur

 

[ex0r]

Instead of looking for a timed button, look for a timer IC. You can set it up so when it receives input from a button it goes to an 'open' state, and once the timer (which is pre-programmed) runs out, it 'closes' again. I am not exactly sure what's involved in doing all of that, but I wouldn't imagine it being too much. I know of a few things in my house that use this sort of stuff. Digital outlets for example, in which you want the outlet to not be active after 'x' amount of time or whatever).

A timer that I see mentioned alot is a 555 timer IC. It does require some electronics experience to build the circuit for it, but it's pretty simple and basic.

Here is a guide that explains how to build one for 1, 4, 10 minutes:

https://circuitdigest.com/electronic-circuits/1-minute-timer-circuit

 

[kellys_eye]

Time buttons are common - they are used for hall way lighting of communal areas.

http://www.cef.co.uk/catalogue/categories/wiring-accessories-and-devices-time-lag-switches

time lag, time delay etc - they are available as electronic or a simple 'pneumatic' version which will do the job more than adequately and will be both cheap and easy to fit as part of a solenoid operate water source.

 

[duke37]

Public toilets are often fitted with timed valves, press to operate and they will automatically turn off after a time.

 

[pusur44017]

A timer that I see mentioned alot is a 555 timer IC. It does require some electronics experience to build the circuit for it, but it's pretty simple and basic.

Here is a guide that explains how to build one for 1, 4, 10 minutes:

https://circuitdigest.com/electronic-circuits/1-minute-timer-circuit

Apologies for getting back so late. I have some experience with electronics, and I find the 555 timer to be versatile, but perhaps being a bit "strict" it dissipates 3mA. This is "much" more than I could do with a modified Arduino. (Which I'd really like to avoid this time around)

Time buttons are common - they are used for hall way lighting of communal areas.

http://www.cef.co.uk/catalogue/categories/wiring-accessories-and-devices-time-lag-switches

time lag, time delay etc - they are available as electronic or a simple 'pneumatic' version which will do the job more than adequately and will be both cheap and easy to fit as part of a solenoid operate water source.

I always find myself at a disadvantage for any electronic project because where I live does not commonly use this as far as I can see. I'd like to go for the pneumatic type, which I hope means I do not have to do anything but connect the wires. I'll have to import this because of the aforementioned problem. I can use this with 12V correct? http://www.cef.co.uk/catalogue/products/12186

Heres my plan:
2x 18650 Li-Ion batteries --- LM2596 based voltage regulator 7.4 v to 12 v --- Above switch --- 2x 12v Water solenoid

I realize using AC mains is easier but in this particular instance, there are access and water issues.

-pusur

 

[kellys_eye]

Yes, we do tend to take many easy-access parts for granted and tend to forget how difficult this may be for others.

Still, the option I suggested CAN be run on a low voltage and is as simple as can be made. Though if you can source the LM2596 boost converter board I'm sure you'll be able to find such 'simple' devices as pneumatic time switches locally too.

 

[pusur44017]

Yes, we do tend to take many easy-access parts for granted and tend to forget how difficult this may be for others.

Still, the option I suggested CAN be run on a low voltage and is as simple as can be made. Though if you can source the LM2596 boost converter board I'm sure you'll be able to find such 'simple' devices as pneumatic time switches locally too.

You'd think, right? I've been looking through every online shop I can think of for this, nothing locally. You do get the mechanical timer switches, looks like kitchen timers, and the electronic kind. Besides both of them being more expensive than importing, the electronic kind will likely consume energy while in standby.

The place where I'm thinking of sourcing the LM2596 board is only a year old and the prices are around 10 times that of say, Maplin. But 99/100 UK retailers won't deliver/has ridiculous shipping costs. This leaves me to order parts from China, but I will not order critical parts from these retailers due to the may be unreliable quality. Also, the parts take around a month to arrive. The other day I found a shop selling the EXACT same item from China at 16 times the price that *I* get. And they get a bulk price! They also still want me to pay for shipping! If I accepted these prices I'd never do any projects. Sorry for the off-topic ramblings, but It's so incredibly frustrating.

-pusur

 

[CDRIVE]

I think I love this topic. Humans that have been soooo unfortunate to have never loved pets will never understand why anyone would go to the lengths that this topic entails! I feel fortunate to be in the camp that does.

Chris

 

[kellys_eye]

and the prices are around 10 times that of say, Maplin.

What country are you located in?

Your distrust of Chinese for critical parts may well be justified but define 'critical' in your own application? The LM2596 module is ex-China isn't it? How critical do you consider that part to be? The stuff I order from China also takes a month (give or take a few days) to get to me in the UK so in that respect you're no worse off than anyone else really.

I get your frustration over the postage charges too - but that's also one area where the Chinese suppliers seem to score as their low, low prices are most often POSTAGE INCLUDED!!! Beats me how they do it - I can't buy the individual parts (an LM2596) here in the UK for less than the Chinese can DELIVER a complete, working module with all the bells and whistles included!!!

If you want to complete this project - and as a cat servant (to five of them) I know exactly where you're coming from and applaud your efforts to make your place safer for them (and you) - I suggest you swallow the 'wait' and get it all from China.

 

[pusur44017]

What country are you located in?

Your distrust of Chinese for critical parts may well be justified but define 'critical' in your own application?

Norway, so no worse off on the delivery, I know that, but it's still a month . Critical being things that have to do with mains power, battery cells, things where the potential for damage is large and mostly controlled by quality. Even though many li-ion cells from China are probably fine, I'd say for this project the critical parts are that and the solenoid valves. Because a failure could cause a water leakage. I'd like to get parts from shops here or not too far away both because of time, and also because of being reasonably protected by consumer law in Norway.

-pusur

 

[kellys_eye]

Try to find a ABB dealer in Norway - I'm sure Norway isn't so 'backward' as to make these switches unobtainium!

 

[gorgon]

Hello Pusur,
As a fellow Norwegian, I got interested in your problem.
If you have installed a valve you need to start in that end, to define the requirements to control this.
Can it be done with a battery operated switch control circuit at all?
The timer problem is the least, as I can see it.
If you need components I can help you with that.
In what area do you live? I live in Østfold.

TOK