Hi all,

I am looking for an electronic sensor+amplifier to detect humidity (leakage) on a laboratory test machine for baby diapers. The horizontal surface is 40 x 20 cm (could be an electronic board with
interlaced copper strips). The minima detection is a drop. The liquid is a water salt mixture.

Any idea ?

Thanks a lot

Vincent QUILLET
ASAlog
Ch. d=E9partemental 60
13320 BOUC BEL AIR
T=E9l :+33(0)4 42 94 06 87
fax : +33(0)4 42 94 06 88
e-mail : [email protected]

 

Hi Vincent,
What kind of accuracy do you need ? How does ambient temperature vary ?

Steve

 

Hi,

That's conductive enough that you could do without an amplifier. If you used your

interleaved copper strips for example, the board with one side grounded and a resistor to positive power. Sense from ground to the board-resistor junction with an analog input (A/D). Voila, you not only can sense a drop but would get some information about how large the leak is. Simply adjust the resistor for a detectable change with a single drop of your standard baby pee and the voltage would go down from there as more liquid accumulates. I can't help you when you get to testing "load" capacity though :^}

Regards

Curt Wuollet, Owner
Wide Open Technologies

 

The application seems interesting, you wrote for baby diapers. Note that if its for this baby comfort is also a point to be considered. For that if you use fine metal print pair of lines or helicals on a soft flexible plastic I hope it will work. The thickness and spacing between lines depend on the minima you desire.

Good luck,

Tanweer Ahmed
Phone: +9221-636 5519
Fax: +9221-568 2972
E-mail: [email protected]