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Interfacing DHT11 sensor to microcontroller.

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dsk2858

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Hi,:?:
i actually bought a temperature cum humidity sensor(DHT11) which produces digital out put whose working voltage is from 3.5v to 5.5v.
But the MCU which i am using can produce only upto 3.3v from the output port pins.As this voltage can not power up the DHT11 .
could any one please provide me the solution for this.

thanking you in advance.
 

skogsjanne

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You run it from 5V and get the 3,3V for the MCU from an LDO regulator.
 

bigdogguru

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i actually bought a temperature cum humidity sensor(DHT11) which produces digital out put whose working voltage is from 3.5v to 5.5v.
But the MCU which i am using can produce only upto 3.3v from the output port pins.As this voltage can not power up the DHT11 .
could any one please provide me the solution for this.

What is the microcontroller you are using in your design? Be specific.

Does it have any 5V tolerant pins/inputs?

BigDog
 

dsk2858

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i am using RF200PD1 MCU by SYNAPSE,which is a Zigbee based MCU. it does not have any 5V tolerant pins/inputs.
I also attached the electrical characteristics of RF200PD1 MCU and DHT11 sensor.
please suggest me which LDO regulator suites my application.
RF200PD1.jpg
DHT11.jpg
 
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bigdogguru

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According to your attachment as well as two datasheets I have on the DHT11, the device has a normal operating voltage range of 3v - 5.5v DC, therefore you should be able to power the DHT11 at the same voltage as the RF200PD1 and no level translation/shifting would be necessary.

BigDog
 

dsk2858

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thanku
when i am connecting the sensor to the RF200PD1 mcu should i add a resister or a capacitor.
 

bigdogguru

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when i am connecting the sensor to the RF200PD1 mcu should i add a resister or a capacitor.

No, not inline.

However, you will need a pullup resistor on the data line from the DHT11 to the RF200PD1.

The datasheet sheets I have recommend a pullup resistor value of 5KΩ for runs less than 20 meters.

BigDog
 
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