Rain Sensor

[grkmr]

Hi all,

I'm responsible to build a rain sensor with the help of PIC programming. However, I don't know in which stage I should use it.
Project is simply to detect water and run an engine using the data that comes from the sensor. I plan such a circuit basically:

Water ---> Sensor ---> PIC ---> (Amplifier if needed) ---> Engine

The main problem is that I don't know what kind of code should I use in PIC, what is the purpose of PIC? Will it work as an DAC(Digital to analog circuit)?

Thanks!

 

[KMoffett]

What's your sensor? Is it conductive...sensing rainwater forming an electrical path between two metal electrodes? Or something else?

Ken

 

[grkmr]

I haven't bought it yet. I also need suggestions about this issue. Do you have any suggestions for the sensor?

 

[KMoffett]

There are many sensors for rain. It depends on what you want to know.
Intensity: http://www.instructables.com/id/Make-an-acoustic-rain-gauge-disdrometer/
Volume: http://www.edcheung.com/automa/rain.htm
Surface wetting, Capacitive: http://www.egr.msu.edu/classes/ece4...ocuments/ECE480_Design_Team6_Final_Report.pdf
Surface wetting, Resistive: http://stargazerslounge.com/diy-astronomer/117125-simple-rain-sensor.html

From your original post, you are looking at surface wetting detection.

Ken

 

[rob_croxford]

What is the purpose of the Engine in the circuit? If your circuit is simply to detect rain then i can see no reason why a pic would be needed. However if u are planning on measuring the amount of rain and changing the speed of a motor respectivly (for insctance) then a pic would be needed. Can you explain more?

 

[grkmr]

actually I want to change the speed but since I couldn't find any sensor that can sense the intensity of the rain, I'm about to change my mind. In all circuits that i found in the internet, they use two wires set up as a spiral on an insulator sheet. (When water drops, those wires will be short) So there's no chance to adjust speed with such arrangement. If u have any creative ideas or circuit elements that can sense the intensity of the water, I'm waiting for recommendations.

 

[(*steve*)]

To measure the intensity of rain, one way is set up a funnel to collect the rain over an area, and direct the water to a tipping bucket rain sensor (sort of see-saw cup arrangement) and interpret the pulses.

The cups are designed so that the water is directed into the cup on the "up" side of the see-saw. When the see-saw overbalances and gets pushed down, the cup empties. An optical sensor is used to detect when the see-saw flips from side to side.

The rate at which rain is falling is determined by either the time between impulses from the sensor, or the number of pulses in a given time period.

 

[grkmr]

Thanks, Steve

I don't think that I have enough time to set up that complex mechanical structure. I'm an electronics engineer and my instructor told me just to sense the water and run an engine which is connected to a lid to open and close it. I just thought that making my circuit sensitive to speed of rain would raise my grade. I think it's not completely necessary, but on the other hand, I don't want my circuit to be a very simple one neither. Looks like it will be.. Whatever.. Thank you all

 

[KMoffett]

Did you even look at this: http://www.instructables.com/id/Make-an-acoustic-rain-gauge-disdrometer/
I think you can gut one of these for the piezo element. http://www.radioshack.com/product/index.jsp?productId=2062397 Amplify (if necessary) and count the output pulses with the PIC. Or integrate the pulses and measure the voltage level with an ADC in the PIC.

Ken

 

[(*steve*)]

Did you even look at this: http://www.instructables.com/id/Make-an-acoustic-rain-gauge-disdrometer/

That is just so cool.

I might just go out and get myself some piezoelectric elements so I can try this.