Automatic rain gauge MS&E - Rain2
The project was started in 2000 and was completed in 2001 caused by a need to provide modern automatic rain gauge to evaluate the experiment in stimulating the precipitation of EA "Hail Suppression".
The project was started in 2000 and was completed in 2001 caused by a need to provide modern automatic rain gauge to evaluate the experiment in stimulating the precipitation of EA "Hail Suppression".
Until 2001 in the meteorological network in Bulgaria for measuring timing of liquid precipitation it is used only classic rain gauge type P-2 (production of the former USSR), which are of the type "floating" with a reception area 500 sqcm. The record is on paper tape.
In floating rain gauge  liquid precipitation falling in float chamber where is a light float. When rising water level in the chamber, the vertical displacement of the float is converted from a mechanical system in the movement of a recorder graph paper tape. The tape is placed on a drum driven by a mechanical clockwork. To avoid a very large volume of the floating chamber the system provides for involuntary discharge upon reaching a certain level of water in it. Used by siphoning device type.

I.    Choice of sensor
Sensor MS&E PIV-4 for automatic rain gauge MS&E-Rain2 is the kind of "Tipping Bucket" (self-pouring) with a reception area 200 sqcm. It's s development and production of Consortium "MS&E".
Rain gauge  of "Tipping bucket" type are with a simple mechanism. Lightweight, metal (or plastic) container, divided into two sections, is set in unstable equilibrium. Under normal circumstances, it is based on one of the two limiter, preventing him to tumble around.
Rainwater falls from the host surface in this section of the container, which is currently above. After a specified amount of water gets into this section, the container loses stability and turn upside to the down position. The collected water is poured from it. At this time the water starts filling the other section. The process continues until there is rainfall. Using different contact devices pulses are received and their number is equal to the number of reversals of the container.
The sensor`s MS&E PIV-4 contact device is optoelectronic, which allows achieving a resolution of 0.1 mm. The presence of a heater under the receiving surface and the electronic thermostat control enable measurement of solid precipitation - snow and hail.

    II.  Developing Data Logger
Microprocessor unit (Data Logger) of the automatic rain gauge MS&E-Rain2 must perform the following functions:
- To measure the amount of precipitation for the current 24 hours and the intensity of precipitation for the current moment and showing them on LCD screen;
- To calculate and display on the LCD the maximum intensity of rainfall and time of its registration for the current day (through key);
Have the following specifications:
- Recording format: year, month, day, hour, minute; rainfall (for each additional minute);
- Storage capacity up to 3900 records;
- Storage of the records in case of power loss - at least 1 year;
- Determination of intensity - for every minute;
- Measuring cycle: starts automatically with the advent of rain, and ends when 5 minutes has been recorded precipitation;
- Input / Output: RS 232 port
At night and in low visibility, when you press the button for the light, it will be switched on and after 30 seconds automatically switched off.

Self-pouring sensor mechanism of MS&E PIV-4