You seemed to have outlined a good solution above. If the only thing holding you back is the AD590's requirement for a 4 volt power supply, you can run your Arduino at 5 volts or use level shifting circuitry between your Arduino and the temperature sensor.(Some text removed for clarity)To reduce its significance temperature compensating circuit is included comprising a temperature sensor, the AD590, an amplifier and two variable capacitance diodes, BB809s. The resultant stability is 1 in 10^4 per degree C. For the middle of the range this is about equivalent to .02 per cent water content per degree C.
You posted a schematic in Post #29 clapp oscillator with compensation What specifically is it that you need that this circuit does not do for you?but i' using arduino to read the frequency output of my oscillator , not for temperature compensation !! the frequency of my oscillator will be variable with soil moisture ( by electrodes ) , how can i change my oscillator to VCO with variable capacitance of the electrodes ?
by Jake Hertz
by Jake Hertz
by Jake Hertz
by Jake Hertz