hygrometer

Description: The sensor in question appears to belong to a specific family of sensors that may not be ideal for use with a PIC microcontroller, as it is considered a low-end sensor in terms of accuracy. Additional information can be found through provided links. The sensor is a capacitive type and requires integration into a circuit, such as an RC circuit. A table is necessary to determine the output values. The HIH-5031 sensor is mentioned as a preferred alternative, being slightly more expensive but compatible with ADC systems. Capacitive humidity sensors can perform well when combined with a 555 timer in monostable mode, allowing for a frequency output proportional to humidity. Achieving an output frequency range of 50Hz to 2kHz is feasible, making it manageable for a PIC microcontroller in Timer0/Timer1 mode. Honeywell sensors have been used successfully, but the current component is not suitable for the intended application. Recommendations for suitable alternatives include the HIH-4000 series from Honeywell, specifically the HIH-4000-003 or HIH-4000-004 models, though the desired accuracy has not been specified.

The HIH-5031 sensor is a capacitive humidity sensor that operates effectively in various applications, particularly when interfaced with microcontrollers such as PICs. This sensor outputs an analog voltage that correlates with relative humidity, making it suitable for direct connection to an Analog-to-Digital Converter (ADC). The sensor's design allows for a straightforward integration into circuits, especially when combined with timing components like the 555 timer in monostable mode, which converts the analog output to a frequency signal. By using the 555 timer, the output frequency varies with humidity levels, providing a digital signal that is easier to process with microcontroller inputs.

In practical applications, the output frequency can be calibrated to fall within a range of 50Hz to 2kHz. This frequency range is convenient for microcontrollers operating in Timer0/Timer1 modes, which can capture frequency changes with high precision. The choice of using Honeywell sensors, such as the HIH-4000 series, is recommended for applications requiring better accuracy and reliability. These sensors are designed for humidity measurement and offer multiple models that cater to different accuracy needs. The HIH-4000-003 and HIH-4000-004 models are particularly noted for their performance and compatibility with various circuit designs.

When designing a circuit with multiple sensor inputs, it is essential to ensure that the selected components can handle the intended configuration. The proposed schematic should accommodate four separate inputs, allowing for simultaneous humidity measurements. Careful consideration of the sensor specifications, including accuracy, response time, and output characteristics, is crucial for achieving the desired performance in the application.What you have sounds like something from this type family of sensors. Not really a good choice of sensor for use with a PIC and actually a pretty low end sensor as to accuracy. There is a little more information located here. Personally I don`t see it as a good choice as there are many good temperature compensated 3 wire devices out there that are

inexpensive. Anyway, the links may help. This is a capacitive type sensor and needs to be part of a circuit. Like an RC circuit. You thern need a table to determine the values outputted. I use the HIH-5031 sensor. Bit more expensive but work straight on ADC. Actually capacitive humidity sensors works pretty good if you couple it with a 555 timer in monostable mode. then you`d get a humidity versus frequency output. An output of 50Hz-2kHz is pretty easy to achieve, and it is trivial for a PIC in Timer0/Timer1 mode to read such frequencies.

I`ve used Honeywell`s, they work good. I intended to have four separate inputs using this schematic. But this component will obviously not work. Anyone got anything that is suitable for the above I intended to have four separate inputs using this schematic. But this component will obviously not work. Anyone got anything that is suitable for the above You may want to give this link a read as to the HIH 4000 series of Honeywell sensors available from Mouser here.

The HIH-4000-003 or HIH-4000-004 would do what you seem to be looking for. You don`t mention a desired accuracy