Low water level warning device

A

adub

New Member
My wife's pond skimmer inlet sometimes becomes blocked by floating plants and the pump will empty the skimmer and suck air....expensive pump and I'd like to make it last...so...

1. How can i sense the water level in the skimmer?

Would the soil moisture sensor that demonicpicaxeguy worked out here:
http://www.picaxeforum.co.uk/showthread.php?t=9528&highlight=soil+moisture&page=2
be the thing?

Opinions?

2. I will obviously need this to be outside....how would you go about sealing a project box to protect it all from moisture......

3. What method of alert would you use? Siren...too many neighbours. Flashing ir beacon and reciever too sunny, rf?

This is going to be fun. Get to dust one of my 08Ms off.

Arvin
 
P

papaof2

Senior Member
How big is the skimmer?

Would a float switch fit inside it (or partially inside it)?

Example switches:

http://cgi.ebay.com/Liquid-Level-Float-Switch-for-Aquarium-Auto-Top-Off_W0QQitemZ180266366672QQcmdZViewItem?hash=item180266366672&_trksid=p3286.m14.l1318

http://cgi.ebay.com/Float-Switch-Low-Liquid-Level_W0QQitemZ250273655617QQcmdZViewItem?hash=item250273655617&_trksid=p3286.m14.l1318

http://cgi.ebay.com/Water-Level-Sensor-Liquid-Float-Switch-Tank-Pool-B_W0QQitemZ330253612434QQcmdZViewItem?hash=item330253612434&_trksid=p3286.m14.l1318

http://cgi.ebay.com/Water-Level-Sensor-Liquid-Float-Switch-Tank-Pool-G_W0QQitemZ330255302805QQcmdZViewItem?hash=item330255302805&_trksid=p3286.m14.l1318

http://cgi.ebay.com/Hartell-J-100-Low-voltage-float-switch_W0QQitemZ130239892276QQcmdZViewItem?hash=item130239892276&_trksid=p3286.m14.l1318

http://cgi.ebay.com/ebaymotors/FLOAT-SWITCH_W0QQcmdZViewItemQQ_trksidZp3286Q2em14Q2el1318QQhashZitem320277354077QQitemZ320277354077

A couple of these are $1US plus $5US shipping. Others are $8US but the seller ships world-wide.

The GEMS brand float switches I've used outdoors have survived well, project here: http://www.picaxe.us/WaterLevel-08.html

John
 
W

westaust55

Moderator
A search for "PICAXE" and within that "Water Level" will find many posts across the internet.

here is a sample:

http://www.picaxeforum.co.uk/showthread.php?t=5313

about three-quarters of the way down page at:
http://www.electronics-lab.com/blog/?m=200802&paged=2

http://www.picaxe.us/WaterLevel-08.html

I have seen a (US ?) company advertising water level kits based on the PICAXE . Just arrived at work and only have the link at home.

Some further details on space and variation in water level etc may help others give more details.

There are IP56 and IP65 rated enclosures available at a price from suppliers in the electrical power industry. These are designed to keep dust and water out and usually incorporate a neoprene or similar gasket betwen the base and lid and use with weather proof cableglands.
Alternatively standard hobby type plastic box could be used and sealed with silicone.


For an alarm,

You could have a tune played by the PICAXE using the TUNE command. might be a bit more community friendly that a buzzing sound. Have two piezo speakers on outside and another inside the house so you can keep the volume down?
 
Last edited:
A

adub

New Member
westaust55 said:
about three-quarters of the way down page at:
http://www.electronics-lab.com/blog/?m=200802&paged=2
Click to expand...
That's pretty much what I need. I was so excited about using an 08M for such a practical solution I just jumped on here before doing any searching. My bad. :rolleyes:

It's a small pond and the skimmer is about 8"x12" with a basket to catch leaves and a filter medium in the bottom and the pump threaded on below that. Not much room for a switch or float.

The skimmer works great and solves the problem of the filter on the submersible pump becoming clogged and having to be pulled up from the bottom and cleaned every couple of nights. Not pleasant. The wife has a bad knee so unless I want to do the kneeling I need a skimmer. Now how to keep it from emptying itself. I don't need to measure how deep the water is just set a sensor to the level where the buzzer needs to sound.

I definitely like the tune route. Much more pleasant than a buzzer.

I have some thin aluminum bar stock that I could lower into the skimmer close to the wall so it won't be interfering with the basket.

I guess I will do a simple flashing LED as a test. Might be enough....we are both at that age were a good night's sleep means only getting up once to make a trip to the facility :eek: , so looking out the window for a flashing led should do the trick.

Ideally, I'd like to turn off the pump with a relay. That would mean a latching relay. Anyone have a suggestion of relay to use. 93 watts at 115v pump is only 0.8 amp if not stalled. I don't know what the stall amperage is. It's a magnetic impeller so even if it jambs the motor still runs till it over heats and shuts off. Don't want that, though that would be better than running dry.

Now to come up with a good way to make an electrical connection to the Al.

Sorry so Long.
thanks for all your input.
arvin
 
E

eclectic

Moderator
Coincidentally, I've just received a pack of those relays.
Excellent for the price.

However, page 3 of the datasheet, from the link, shows

maximum current 0.5 A at 125 V AC.

Therefore, too small for Arvin's task.

e
 
W

westaust55

Moderator
good spot eclectic.

Jaycar have a latching relay with max contact voltage rating of 240Vac and max current rating of 2A contacts but not clear if these both apply together.
CAT. NO. SY4060

nominal rating is 12Vdc for the coil.
Stated Maximum voltage for set and reset is stated as 8.4Vdc so might just work at 5Vdc or 6Vdc.
Needs research to check contact ratings are really suitable.
 
M

Michael 2727

Senior Member
Hi Arvin,
Here's what I'd use-
There is a more complicated AC version where the probes will
last indefinitely, but this should last a few seasons.
The hard part will be the power supply, cutout relay 110V side etc,
waterproof enclosure and wiring it all up. :)
 

Attachments

hippy

hippy

Technical Support
Staff member
A 0.5A 125VAC relay should be able to switch current to the coil of a much bigger relay though which handles the final motor/pump. The two combined makes for one high-load bearing latching relay.

That's how I control my heating system. It's not latching but a small 5V relay switches mains to the coil of the chunky 20A 250VAC relay. It's also why vehicles have relays because the switches themselves aren't rated for the current being switched.
 
You must log in or register to reply here.
Top