How to identify x type capacitor?  Are these better than polyester capacitors? I used polyester type but never used X type ones.

Thanks in advance.

If you want to build your own SSR, you can refer http://electroschematics.com/6267/do-it-yourself-solid-state-relay/

Thanks for sharing!!!!!

Hello,  I am looking for w5100 ethernet shield or clone. Any one knows if its available in Bangalore and cost?

Thanks in advance.

Replace the USB hub with some other load like 25Watt bulb and check.

Thanks for Sharing.  Nice app!

Another method you can think of measuring the water level is capacitive sensor method.  Capacitance will increase proportional to the water level.  You can use capsense library from arduino play ground for the same.

You are welcome :-)

You need to connect PIN10 to VCC.

I used a PIR sensor module for the motion detection for a security light and fixed everything in a small transparent plastic box (PIR sensor module also inside the box).  It is working fine without any issues.  Whenever there is a motion it switches on the light.  So I believe it works for your case as well with out any issues from behind the clear glass. Just give a try!!

You are welcome :-)

Yes, you are right.  S is where you will connect your digital output.  Also you can refer link for more knowledge on relays http://arduino.cc/playground/Main/InterfacingWithHardware#Output

You can use any of the digital outputs, use/define the same pin in the sketch to operate the relay.  Good Luck!!!

Thank you dc42 and Mike for your detailed explanation.  It's a great learning.  I have chosen a 75°C @ 15W (natural convection) heat sink for my application. I believe its bigger than what is needed, but I feel its no harm.

If you want to use only Ultrasonic, you can give a try replacing the existing sensors with water proof sensors.  Have a look at this link http://www.alibaba.com/product-gs/575210695/40KHz_waterproof_ultrasonic_transducer.html?s=p