I've been building a circuit where I'm controlling a motor using a bluetooth module + phone. I've been having some problems, which mostly are fixed (see topic: previous topic).
The main problem I'm facing at the moment is that the DC motor is causing quite some noise on the power line (even if I power the motor directly from V+). I've managed to reduce this by limiting the motor current (using resistor R13) and put in some capacitors + a diode (D3) over the motor. However there is still siginificant noise.
Therefore I would like to know if there is a way to reduce the noise on the power line even more beside having these capacitors and the diode(D3), when the motor switched on (or have additional capacitors)? And what capacitors are best in reducing noise?
See schematic below: 
Answer
I've been testing with bigger capacitors, and a 1000uF (C5) solved all the issues. Unfortunately I won't have enough space in my casing for such a big capacitor. But even a 100uF made it a lot better. I will see what I can squeeze in.
@ Sean Houlihane, I'm not able to solder directly to the motor or very close to the brushes. The motor is placed in a very tight space in the casing and a couple cm away from the print. Luckily replacing C5 did the trick well enough.
@JWL, unfortunately the pie filter won't be an option, since the motor is also powered from the 3.3v so they share the same power source. I don't want to power it directly from the LIPO battery since the current the motor draws at 4.2 volt is too high. At 3.3 volt the current stay nice and even.
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