GLOBE Soil Moisture Meter
GLOBE Soil Moisture Meter
| Desc | Quantity |
| 68 k ohm resistor | 1 |
| 6.8 k ohm resistor | 1 |
| 15 ohm resistor | 1 |
| 2.2k ohm resitor | 1 |
| 1.2k ohm resitor | 1 |
| 0.1 µF capacitor | 2 |
| 1000 µF capacitor | 1 |
| 1N4733 5.1V Zener diode | 1 |
| 555 timer IC | 1 |
| LM324 IC | 1 |
| Enclosure (at least 1"x5"x3") | 1 |
| alligator clips | 3 |
| banana plugs | 2 |
| SPST normally open pushbutton switch | 1 |
| 4P4T slide switch (or two DPDT switches) | 1 |
| 9v Battery | 1 |
| 9v Battery Clip | 1 |
| 14pin solder tail IC socket | 1 |
| 8pin solder tail IC socket | 1 |
| solderable breadboard (at least 2"x3" ) | 1 |
Other useful supplies:
22 guage solid core connection wire
soldering iron
solder
flux paste
DMM
| Soil Moisture Content | AC Voltage |
| > 90% | < 0.20v |
| 80% | 0.45 |
| 70% | 0.675 |
| 60% | 0.9 |
| 50% | 1.125 |
| 40% | 1.35 |
| 30% | 1.575 |
| 20% | 1.8 |
| 10% | 2.025 |
| Dry as a bone | > 2.25v |