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Author Topic: DHT11 with external power  (Read 428 times)
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Hi, my DHT11 temp sensor works properly if my arduino is powered by a usb connected to a pc. But if it is powered by other external power the reading of DHT11 bounce.
How can I fix this problem? This problem doesn't occur on my other sensors like photocell.
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Shannon Member
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Sounds like either your alternate power is not stable, or you have shared the ground wire from Arduino to both
supply and sensor - keep sensor ground wiring separate from any ground wiring that takes significant current.
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External power should be at least 7Volts and max 12V
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Rob Tillaart

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I tried using a DC 9V adapter and a 5V phone power bank. But both give me the unstable DHT11 readings.
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Can you post a drawing how you connected everything?
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Rob Tillaart

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