More info on L4620 liquid sensor chip

[Nicmus]

Hi Brian,

Thanks for your input.
The main reason I was trying to use this chip is that with only a few external components you can safely detect if the level gasoline is under a certain level.
If I got the specs correctly the chip will do all the work if you use a capacitive sensor.
For fuel level detection in my case I’m limited by the size of the sensor and I’m not allowed to change any of the inner components.
I’m working on a similar sensor to the one presented on the site you suggested.
Due to very small change in capacitance from the sensor I’m targeting higher frequencies. So my tests show that a 14 stage binary counter with built in oscillator (MM74HC4060) might just do the job.
I will need a small PIC to process the output of the divided down frequency.
Unfortunately I didn’t have the chance to work on this project lately, so I don’t have too much progress to report.
I will post my findings as soon as I will have news.

Best Regards to all PIC users,

Nick

[tanksalot]

Brian:

I'm an electrical "newbie", but your post gave me some good ideas. I have a digital peristaltic pump which will turn on when the resistance on an input jack RISES to a certain point. Naturally a dead short will turn it off, but the "turn on" point can be adjusted. I'd LOVE, LOVE to use this pump to water plants when they need watering, and can envision a high-hanging pot with two stainless probes on opposite sides of the pot determining the need to water ( or not). The two probes would output a resistance that, when low enough, would cause the pump to turn off and stop watering. Then, when the plant dries to the point when it needs water, the pump would turn on.

How can I create a circuit using a 555 chip that will do this??

Hopefully, thanks in advance

Stan F.

[BrianT]

Take a look at

http://www.emesystems.com/OL2mhos.htm

HTH
BrianT