Hi there all
I have build a device which needs to rotate a tube slowly (using a 28BYJ-48 unipolar stepper motor; driven by a ULN2003A) while an ADC (ADS1115 connected to microcontroller by I2C) collects data from a number of sensors' outputs.
My problem is noise collected by the ADC that is worse when the motor is running ---- this results in a saw-tooth pattern superimposed on the signal collected.
The motor itself is distant to the ADC and sensors so thus I assume the magnetic fields in the vicinity of the motor are not at fault.
More likely causes for this phenomenon:
> Unstable power supply to sensors which result in fluctuations in output signal
- This I hope to address by supplying the ADC and sensors with their own linear regulator and some filtering caps
My question is whether or not the circuit would benefit from additional flyback diodes (over and above those within the ULN2003)?
> If so, also some advice as to an appropriate (smallest possible SMD) diode and schematic for connection.
Thanks in advance.
I have build a device which needs to rotate a tube slowly (using a 28BYJ-48 unipolar stepper motor; driven by a ULN2003A) while an ADC (ADS1115 connected to microcontroller by I2C) collects data from a number of sensors' outputs.
My problem is noise collected by the ADC that is worse when the motor is running ---- this results in a saw-tooth pattern superimposed on the signal collected.
The motor itself is distant to the ADC and sensors so thus I assume the magnetic fields in the vicinity of the motor are not at fault.
More likely causes for this phenomenon:
> Unstable power supply to sensors which result in fluctuations in output signal
- This I hope to address by supplying the ADC and sensors with their own linear regulator and some filtering caps
My question is whether or not the circuit would benefit from additional flyback diodes (over and above those within the ULN2003)?
> If so, also some advice as to an appropriate (smallest possible SMD) diode and schematic for connection.
Thanks in advance.