- Microcontroller and allied circuitry: Microcontroller being an intelligent device can help anyone easily optimize the system at very low cost they have an exact understanding about the field requirements and technical blocks. It helps reduce the cost of the different electronic components in the peripherals and allied logics with the use of simple software commands. It intelligently replaces hardware logics built with diodes, transistors etc by the simple software simulations.
- DTMF decoder: This is a universal IC available in the market used for decoding the DTMF signals send from the mobile phone into the logical high levels.
- Tone Generator: Tone generator is also a low cost astable mode clock wave generator built around IC 555 and effectively used to deliver different tones using a single IC and multi switching logics.
- Driver stage and relay with isolation circuits: Driving the output relay requires special skills as it is very much important to prevent the resetting of the microcontroller circuit when the system is in high power application. Optical isolator circuits have been built around standard things available in the market.
- Output sensing stage: It is important for the farmer to understand whether the pump is really ON or OFF after sending the ON command. Many systems in the market provide a feedback from the MOTOR ON RELAY as soon as it is activated from the microcontroller command. This is a virtual acknowledgment before the pump starts. There is a possibility that due to low voltage or single phasing, Auto Switch does not start the pump and still he gets the feedback of MOTOR ON. Nano Ganesh – GSM actually senses the output voltage of the starter and converts the signal into the digital level with the help of voltage converters. Hence, farmer gets the MOTOR ON SMS or call only after the pump has been physically started and picked up.
- Infra red sensing and processing stage: It is a special pair of infra red diode circuitry to sense the opening of the panel door and physical movement of the person standing in front of the panel. This component allows farmer to get an alert call when unauthorized person opens the door. A pair of infra red Tx-Rx (transfer and receiver) is a low cost solution to achieve this utility.
- Antenna for GSM modem: As the whole system is installed inside the metal box, there is a strong need to boost the GSM signals with adequate matching antenna. There are so many GSM modems available in the market which provide antenna by just winding a coil of 14/36 SWG wire without appropriate connectors. Due to this, 80% of the transmitted and received signal power is wasted or leaked. To provide strong signals irrespective of low GSM signals in the rural area, a 50 ohm matching antenna and circuitry is incorporated in the antenna stage. Even for the length of 10 cm cable of antenna which carries signals from module to the connector, a properly designed R-C network with matching cable has been adopted.
Layout and Operation
Nano Ganesh- GSM is a wireless controller that receives the controlling demands from the farmer’s mobile phones. The controlling demands may be to turn the motor on or off, or to check the status of the power or the load. The GSM modem is installed in the starter panel which are normally made of galvanized or M.S. Sheets and are placed outdoor in the farms or near the water pumps. The unit contains a simple hinged door for the panel to secure it with lock and key arrangement. It also has an external antenna for the GSM unit. The power supply to the GSM unit is supported with additional battery back-up and the unit also contains relay contacts in order to control the no volt coil of the starter or auto switch. It is equipped with Auto/Manual switch in case of emergency need of irrigation. There is also an infra red sensor installed in the starter panel so that whenever a panel door is opened, an alert SMS or call is sent to the farmer’s mobile phone.
Mr. Ostwal says, “The Nano Ganesh – GSM unit comprises of state-of-the-art life tested technology for providing a feedback of power or load on-off status with the help of simple audio tones, hence making system linguistic free.” The GSM unit easily connects to the starter panel with one of it’s wire connected to the starter input and the other one to sense the status of the Load. Whereas the other control connection of the unit goes to the starter No Volt coil of the Auto Switch. It also has a neutral or an earth wire that must be connected to the GSM unit in order to generate 1 Ph, 230 Volts power supply.
