Main components | Part number | Source | Cost (US$) |
Microcontroller/cellular board | Feather 32u4 FONA | Adafruit Industries | 45 |
Cellular antenna | Sticker-type GSM | Adafruit Industries | 3 |
Rechargeable battery | 3.7 V LiPoly, 2500 mAh | Adafruit Industries | 15 |
Terminal block | Spring terminals | Adafruit Industries | 3 |
Low-power timer | TPL5110 | Adafruit Industries | 5 |
Weatherproof enclosure | NBF-32002 | Mouser Electronics | 9 |
Miscellaneous (protoboard, headers, resistors, connector) |
| 5 | |
Total |
|
| 85 |
Soil-moisture sensors (4) | Watermark 200SS | Irrometer Company | 120 |
SIM card, cellular data plan | 1 MB/month, 1 year | Embedded Works | 30 |