Although 3G/4G coverage is not prevalent in majority of villages afflicted by human-elephant conflict, GPRS (General Packet Radio Service) coverage is available in many of the villages. Thus, it may be possible to replace the RF communication configuration - involving elephant detection devices communicating via the field transmission stations to the village base station - with GPRS modems fitted to each elephant detection device.
In this alternative communications scenario, the elephant detection devices would transmit SMS messages, using their GPRS modems containing the following data:
- Is elephant detected (yes/no)
- Which elephant detection device is this (e.g. number 14)
These SMS messages could be sent to the village base station, where they would be processed, and the data regarding location of elephants output to the LED signboard, sent to villager's mobile phones, and uploaded to internet.
A suitable GSM/GPRS/EDGE modem is made by SparqEE [see here], along with a Raspberry Pi shield (total cost £70). Although slightly more expensive than the RF transmitters already chosen, this would eliminate the need for field transmission stations, thus reducing overall costs. In addition, the SIM900A MODEM WITH TTL is significantly lower-cost (Rs 875 / £9 gbp in India) and can be easily connected to the Raspberry Pi.
One of the main aims of the automated elephant-detection system is to be as flexible as possible regarding communication and hardware configurations, making it easier for afflicted villagers to adapt it their needs/budgets. In fact, at the final stage of the project, I plan to test multiple components, depending on what is easier for villagers to obtain locally. Thus, this alternative communications configuration will be tested subsequently to the planned RF configuration.