Hmmm good idea. You can detect snow with antenna radar but you want a sensor.
How about a combination of a sensor to decide a) presence of water b)presence of temperature and c) presence of reflection and triggering or better a microcontroller will decide if all are true
a) and b) can be done easily, even people have posted tens of design in web. hmmm let me think for c)
May be the deicing sensor concept can help. Basic parts are temperature sensor, precipitation sensor and logic circuit. Temperature sensor can be made by means of NTC resistor. Precipitations sensor is made as two poles greed on PCB and heated to about 40 degree Celsius. Rain, snow and high air humidity (fog) will increase conductivity of greed.
Snow can fall at temperatures from 4 deg. C and lower. At higher temperatures falls usually rain.
Where is the snow you are detecting. Are you above the ground and want to see if snow is on the ground. Have you collected snow in a container (like rain gauges)? If it is collected, your container can have a screen on the bottom so that rain empties and snow stays.
Hello Koky and all the others.
The epsylon of the water is very high. The epsylon of the ice should also be very high.
High epsylon means high capacitance. Probably just a capacitance meter can do the job.
We had discussed before something similar. The idea before was to measure water level.
You can use a simple oscillator made with a cmos inverter 74hc14. A resistor (like 1M) from the output to the input. And a capacitor from the input to ground.
This capacitor is made out of 2 copper ( or any other metal ) bars or wires equally spaced and vertically placed. Spacing=2 mm, lengh = 50cm should be a good start....The copper wires can be those used in house electrical installations, The plastic isolation may be left to prevent shorts... it should still be possible to see good capacitance variations even with the plastic insulation...
The output frequency is proporcional to the capacitance ( ~1/RC). This frequency may be measured by a microcontroller like a PIC.
From the capacitance you should be able to get the snow level.....etc..
Try to measure such a capacitor using one of those new multimeters that can measure capacitances,etc...
Greetings to all.
S.
thanks for suggestion,
the two way that i think are:
A)
themperature, reflection light or color detection and humidity detection
B)
radar detection, i have found a cheap radar module at 24ghz , 20 mt (15€), i will test it with little rain of polystirole with themperature condition
about capacitive metode, i have a perplessity, becouse the snow on the road must be detected early, and capcitive metode want some centimeter for measure