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Plant Monitor

Tonight I threw together a quick plant monitor. I followed the directions for the Botanicalls Twitter DIY to build a moisture detection circuit (I used a 2N3904 transistor). It works pretty well. I found that the analog readings tend to be quite high and do not vary much (450 for dry soil, 545 for moist soil, 555 for a glass of water). I think these variables probably need to be adjusted to match individual conditions.

The plan is to move this quick and dirty Arduino prototype to an ATtiny13 with wireless data transfer and solar power. Using the tiny13, I should be able to monitor 3 plants (without disabling the reset pin). Here's my Arduino code and pictures.

int PROBE_PIN = 5;

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  int val = analogRead(PROBE_PIN);
  delay(1000);
  Serial.println(val);
}
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