How they work
The KIRACCS provides a reading by measuring the electrical resistance of the sensor. The sensor is provided with a 3v3 and the reading derived by measuring the sense voltage relative to ground. The lower limit is zero resistance (ie short to ground) to provide a reading of 0% and the upper limit of maximum resistance (short to 3.3v) provides a reading of 100%.
The Keene Sensor board provides the ability to measure light (light dependant resistor), temperature (thermistor) or open or closed condition (magnetic reed switch). A jumper switch selects the desired sensor and connection is via 3.5mm jack.
The thermistor will provide an approximate reading of 93% at 100 degC 50% at 25 degC and 15% at 0 degC. Select this option by placing the jumper across J1 (only).
The LDR will provide an approximate reading of 0% in complete darkness and 100% in extremely bright light. Select this option by placing the jumper across J2 (only).
Magnetic Reed Switch
The Reed switch will give a reading of 100% when activated (magnet closer than 2cm) and 0% when open (magnet more than 2cm away). Select this option by placing the jumper across J4 (only).
The above data is proximate and is designed to give you enough information for initial set-up. For precise control it is recommended to connect the sensor and take note of the readings over a period of time as and when the desired conditions are met.
Can I use other sensors?
Of course. There is a connection point labeled J5 on the sensor board. This can be connected to a soil moisture sensor, or other sensor that provides a variation in resistance , ideally within the range 0 ~ 50Kohm. If the sensor resistance is outside of this range you will likely find that it provides such a small fluctuation in readings it may not be suitable. Before connection ensure that any jumpers are removed from J1, J2 or J4.
The diagram of the sensor board is provided for your reference. If you have any detailed technical enquiries please get in touch.