If you use electrodes for sensing the problem of scaling electrodes comes into picture if you use a simple dc for sensing. I suggest you can use a toilet flush arm with a float and connect it to a sealed potentiometer and sens the resistance. And sending the data can be done by sending pulses on the power line to sensor controller. Effectively only two twisted wires can be used between overhead tank and the control unit with out any polarity on wires ( wires can be connected in any direction )- Use a bridge on the sensor unit for dc power.
just follow three things, i am sure it may help you in your projects..
1. check the resistance of water using multimeter e.g. 10k per cm ... etc.
2. three wires of ground for measuring hi.. medium ... low should be there along with one wire foe 5 v power supply..
3. if possible use ULN 2803 for amplification of current.. though its output is inverted .. but you can use not gate between microcontroller and uln...
just follow three things, i am sure it may help you in your projects..
1. check the resistance of water using multimeter e.g. 10k per cm ... etc.
2. three wires of ground for measuring hi.. medium ... low should be there along with one wire foe 5 v power supply..
3. if possible use ULN 2803 for amplification of current.. though its output is inverted .. but you can use not gate between microcontroller and uln...
the flush arm idea is good.
but there is also nother way is to use reed switches outside the bucket ot tank and use a magnet attached to the inside wall of the tank which can slide over it means you need a plastic base under it.
this mechanism will give you more life but not that precision which u may find in pot resistance.
best of luck
bye
nice idea.
even if it indicates the level using some led it will be enough for me.
but the documentation provided with the idea is not clear.
where and what shld i connect the two coils with?
i am doing the project of liquid level control usinf pic16f877a. in the circuit diagram we are having dac ad7302 and powe amplifier LM675 but these components are not available in market. can any one sugest any other component for these cpmponents
How about rigging a passive float, maybe riding up and down a vertical rod at the side of the tank. Then use a **broken link removed** or similar to measure the distance to the float.
I've seen a few articles (like **broken link removed**) where guys measure salt levels in their water softeners with various IR or ultrasonic sensors. They don't need a float since salt reflects both IR and sound just fine.
Ultrasonic might bounce off liquid ok, I've never tried it. IR might, but probably not. I guess it would depend on what liquid you're measuring too.
**broken link removed** I don't know. I just click on the link and there it is. I open my eye and read. I've never been to hometoys.com before, so I can't imagine how I could have signed up for anything.
Anyway, the Maxbotix sensors are dead easy to use. Get one and try it for yourself.