Connecting a DHT11 sensor with XBee Series 2 without external microcontroller using Java

Question

Hi! I am working in a project with Xbee Series 2 and Java, and I would to know how can I connect the digital output of DHT11 to a Xbee module's input and read the samples from my Java app, because I have been looking for a Java library for DHT11 and I haven't found anything clear. Thanks in advance!

Answer 1

Your sensor is outputting more than 3.3V. You will need to use a level shifter to lower the peak voltage of 4.2V down to 3.3V or what ever your VREF is at.

Comments

Thanks for your reply, but my question was rather that once everything is connected, it is possible to read without microcontroller the samples send by the DHT? and if that is possible how could I do it?
Sorry for the misundestanding.

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Yes it is. You don't need an external processor between the XBee and the sensor.  All you need is the proper circuit on the remote side. As for the other side, you code only needs to be able to read the radios ADC packets and convert it accordingly.

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My code is able to read the ADC packets because I've already done with other analog sensors, the problem is that DHT is a digital output sensor and I've no idea how to read it because I haven't found any library for Java. Any idea?

Answer 2

From what i am reading, it is sounding more and more like it is not using a standard UART interface. I would suggest you contact the manufacture of the device and verify what the output of this device is. If they are using a Digital IO line for both input and output as it seems to indicate, then you will need to use an external processor that is capable of using the same pin for both Input and output and then convert that to 3v CMOS level interface for the XBee.

Comments

Ok thank you so much for your effort. I will follow investigating about the issue.