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Hello everyone …
I am back here after a long time…
I have used ADC of atmega15 to interface moistue sensor.When i am connecting the ADC input to vcc and groung,its giving me correct output that is 5v and 0v resp.
My moisture sensor is also workng perfect independently. But when i connect my sensor output to ADC input,my sensor output goes low and output of ADC is 0v…Plz help….
The moisture sensor i am using is a simple voltage divider.
Two resistance of 10k and 1k in series. Output from the junction of both. One side Vcc other side probes with one probe ground.
When the probes goes into moisture,the probes get shorted and we get output.When there is no water , the output is Vcc
It is given in the datasheet like “The user is recommended to only use low impedance
sources with slowly varying signals, since this minimizes the required charge transfer to the S/H
capacitor”.
So try changing the value of resistors to small value, still keeping the ratio same.
If its not working, may be your sensor is getting loaded while connecting to the ADC. Try connecting a high valued resistor like 100k in series.
hello frndz…
can anybody help me to interface moisture sensor using 8051……i need the circuittry of sensor
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