This is an extension of a previous post concerning me building a water tank level indicator.
After much searching and evaluating different solutions I have come up with three questions that I would like to pose to the more senior members.

1. The voltage range for several solutions run from 5 volts up to 24 volts. As I do not want to have a automatic pump connected to this circuit I believe that the voltage required with be in the 5 - 12 volt range.
My question is, should I use AC or DC voltage?
A few designers call for AC versus DC as there are concerns regarding corrosion or a build up on the tank water level indicators.

2. There are several design considerations as to the type of wires that will be immersed into the tank.
From what I have been able to find out using aluminum wire is preferred to copper. A couple of designs call for the use of brass screws or bolts as the connection points.

Years ago one could find aluminum wire easily but due to past problems it is a rare item or so I believe. If I was to go that route (Aluminum) is there a ready source of wire available i.e. CAT 5 cable etc.

3. Most designs call for a buzzer to be installed to notify of a full water level. Some use a Piezo speaker, others a buzzer and even one using a door bell. I believe that the selection of the alarm will depend upon personal choice and voltage used.

I am sorry about the length of this post but I want to provide as much information as possible.

Here are few links to water level indicators:
http://s2ptech.blogspot.com/2012/04/simple-water-level-indicator.html#.UU0eWjd3fa1

http://www.extremecircuits.net/2011/09/simple-water-level-indicator-cum-alarm.html

http://archive.siliconchip.com.au/cms/A_30607/article.htm

http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt6.shtml

http://www.brighthubengineering.com...3-build-your-own-home-made-water-level-meter/

 

Uncoated (uninsulated) stanless steel wire, or aluminium wire, are easily available from someone who does MIG or TIG welding, they buy these wires on large spools and should be happy to sell you a couple of metres of wire.

 

I agree with Roman on stainless steel electrodes. My favorite AC driven liquid level detector circuit:
http://www.simplecircuitdiagram.com/2010/10/19/cd4093-water-level-sensor-detector/
I've built several versions. That one is for just one level. But, you can use one oscillator (on the right) and multiple detectors (on the left) for multiple levels.

Ken

 

Looks like it is a 3N100 or a 3N108. Some high voltage SMDs from Motorola.
Google the Datasheets. Easy to find.

 

Looks like it is a 3N100 or a 3N108. Some high voltage SMDs from Motorola.
Google the Datasheets. Easy to find.

Wrong thread?

Ken