Hello. I'm currently working on my school project; a water deposit simulator made with logic gates, that can simulate a container that retains or leaks water. But now i'm taking it to another level, i'm gonna try to build with someone's help, a real water container with eight water level meters. In the end of that sensor/meter there would be a bcd encoder, but i don't know exactily if there are commercially available encoders.

I tried to use a salty water to enable a logical state, but it seemed unstable with ttl circuits.

I'm really sorry for my bad english, i can't express myself with the right words.

 

Have you considered using float switches instead of using salt water?

Conversion to BDC is usually done with software. However, if you have only eight levels, then no conversion is required. "7" in hexidecimal is the same as "7" in decimal. Your LED display driver won't know the difference. You would not have a problem until the eleventh level (the "A" level).

 

Hi.
Float switches are much more expensive than other solution, as this is a simple and cheap project. I considered to use salt water because it's an easy soluction to activate a logic state, altough it seems unstable to keep that logic state, because the voltage on the end of that circuit is not stable.

I'm using a 74LS191 as a water container simulator. I'm planning, in the real water container, to make load (in the 74191) of the sensors data.

 

Originally posted by espeon@May 19 2006, 05:35 PM
Hi.
Float switches are much more expensive than other solution, as this is a simple and cheap project. I considered to use salt water because it's an easy soluction to activate a logic state, altough it seems unstable to keep that logic state, because the voltage on the end of that circuit is not stable.

I'm using a 74LS191 as a water container simulator. I'm planning, in the real water container, to make load (in the 74191) of the sensors data.

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you should use comparators, it is bette solution than measuring with TTL. And if you don´t plan it for some longer time (because of the electrodes) you can use higher current for measuring.