How to interface humidity sensor with PIC18F45K80

[Djsarkar]

Hi
I have humidity module. I want to interface with



T microcontroller works on the digital signal. If the sensor gives an analog signal, the microcontroller will not be able to read it.

Do I need an external ADC?
Should I use inbuilt ADC in pic micro?

 

[Diver300]

The has a built in ADC, and that would be the easiest to use.

Almost all ADCs work best with a signal that changes over most of the range of the supply voltage. The will probably be running from 5 V, so the ADC will work best if the signal from the sensor covers a good proportion of the 0 - 5 V range.

You don't say what the range of the humidity sensor analog signal is, but if it's not a voltage in the range 0 - 5 V, and it if doesn't change by more than about 1 V in the humidity range you are interested in, then some sort of signal conditioning would be needed or would help.

 

[rjenkinsgb]

With an analog sensor, you would normally use an ADC within the PIC.

However, the module you show has a serial data output, not analog.
Data sheet here; the three and four pin versions work pretty much the same:

https://components101.com/sites/default/files/component_datasheet/DHT11-Temperature-Sensor.pdf

You need to use an I/O pin configured for "open collector" (or switch it between out and in using the TRIS bit), plus a pullup resistor from the data line to 5V.

Edit - here is an example for using one with a PIC18F:

DHT11 Sensor Interfacing with PIC18F4550. | PIC Controllers

Interface single wire DHT11 sensor with PIC18F4550 and read the value of Temperature and Humidity from DHT11. Display these Temperature and Humidity values on a 16x2 LCD.

www.electronicwings.com