Servo Noise Isolation

LoopyByteloose

I have been looking at a generic wheeled robot design in December Nuts and Volts and it shows using a diode from the +V and a large capictor from +V to goung in order to block servo motor noise from going into the power supply.

Like this:

+5 volts supply >

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<Diode for blocking Noise>

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+5 to R/C type servos
················································································· |
··················································································| +
················································································===·· 330 mF capacitor
· ··············································································· | _
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················································································· V···· To Ground (-)


Alternatively,

Is it just okay to separate the BasicStamp from the servo motor supply by providing a separate 7805 with appropriate capacitors·to the motor and allowing the Stamp to use its on-board regulator for the digital?

It seems to me that it would be as good or better?

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G. Herzog in Taiwan

allanlane5

Yes, a separate 7805 for the Servo's provides sufficient isolation.

Make sure the BS2 and Servo's have a common ground, though, the Servo uses the common ground to correctly read the commanded pulse width.

And I don't think Servo's are nearly as noisy as 'pure' electric motors. They do pull current in 'pulses' though.