not sure how to go about this...

ok i just recently got an arduino based microcontroller (the freeduino 1.22). anyway, ive been playing alittle bit with it… and i really want to figure out how to incorporate this with my aquarium setups. i want to start off by water level notification… 3 lights to show level (all 3 on… high…2 on…gettin low… etc)… and i was thinking of doing a homemade float switch idea, but im not sure how to make the sensor(s) i was kind of thinking using IR leds and have them hooked up to as the water level went lower a lever would start to block a set…causing a light to go out… any help would be great

If you havent already found this:

You should checkit.

yea thats really the only one im come across… he uses a companys float switch… where as i want to kinda make my own but just not sure what to use for “sensors”

What sort of accuracy do you need?
You could make something really simple with a two or three pairs of LEDs and photodiodes and a float in a tube.

You could use a float in a tube and measure the inductance of the coil. This would change with a change in water level as the magnet (or just iron) was lowered more into the coil. Although I first drew this as wake detector it will actually measure levels as well if you drive it like I say.

well my approach at it was more like the floats you see in toliets. so in this case…being itll be way smaller… the float would be a ping pong ball, attactched to an arm. i was thinking of 3 “zones”… so when the tank was full… all 3 notification leds would be lit and the other end of the float arm would not be blocking the ir leds… or w.e sensors… then as the float went down… the other end of the arm would brake a connection to a set of the ir/led’s/etc… causing a notification light to go off…

if your going that route just use a micro switch on the end of the arm, when its above a level it turns off the switch

not very precise but A)cheap B)easy

Why not try using a ultrasonic sensor to measure the water level, such as the Ping((( (sorry can’t find the website to buy these from). It would be the simplest to set up (edit: in terms of hardware, should be a simple plug and play) but I don’t know if your fish will get really annoyed with the sonar (I imagine it could be as if some kid was tapping on the glass so fast you couldn’t even see it!) although depthfinders for fishing don’t seem to scare the fish away (now that would be pointless :o )

or this:

If you had a piece of twin core flex with resistors soldered across each 1/2 inch .As a resistor dried out the total resistance drops. Sense the resistance with an arduino pin .

I think the answers from Osgeld and MikMo are the best. Use three switches or three floats if you want that many. It would still be cheap and simple.

How about this float switch:

I’ve never used it, but bought a lot of other stuff from this seller and all was good with them.


Yeah, the ebay evel switch looks like its smaller and less intrusive than the one from seeedstudio.

Ooooh! You could hook the ping pong ball/arm assembly to a potentiometer dial! As the water level drops, the resistance would change in the pot and you could use a RGB led to fade from green to red! Now that would be cool!

Haha, it’s probably not the best solution… but it looks fairly accurate…

I hope your fish don’t mind having a Wii-mote pointed at them at all times… :stuck_out_tongue: