Hi, my circuit is as follows.
When I disconnect the Bluetooth module from the system, I measure room temperature as 25 C.
However, when I connect BT module to system, there is a noise in circuit. This will cause high voltage on LM35 pins and false measurement of temperature. Also, this noise increases time by time.
Can someone help me?
Thanks in advance.
Where are the bypass capacitors for your devices to the noise is shunted to ground?
One is between BT terminals(5V-gnd) and other one is between Arduino terminals(5v-gnd)
Both are 680nF
Then where do you find the noise?
May 29, 2021, 12:57am
The BT module should not be connected to the TX/RX pins of the Nano.
Those pins are already used by the USB<>Serial chip.
Use SoftwareSerial on two different pins.
You didn't post any code.
Did you use the more stable 1.1volt Aref for the LM35 ?
What are you trying to do with that microphone.
A boost converter could introduce switching noise into the setup.
Between ground of arduino and ground of boost converter
While I was uploading code to arduino I disconnect RX-TX. However, during normal operation, it has serial communication with bluetooth. So those pins should be connected.
With some piece of code, I detect coughs of user with microphone. It works fine
September 29, 2021, 6:15am
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