Resistance to Frequency Board
The resistance to frequency board takes
a resistive sensor and converts the resistance seen into a frequency.
The resistance sensor could be a cadium sulfide solar cell (Light
Dependent Resistor) , a thermistor for a heat to resistance reading, a
gypsum block soil moisture sensor, a moisture to resistance sensor, a
potentiometer for motion to resistance and so on. Below you will find a
resistance to frequency plot. The RtoF board is used with a companion
board to supply voltage to the RtoF board and also to take the board's
output and switch a transistor on and off with the frequency generated.
The companion board also provides an amplifier so you can hear the
frequency as it changes.
The RtoF board provides an AC signal across the resistive sensor so
items such as moisture to resistance and gypsum block soil moisture
sensors can be safely used without corrosion.