Power supply problem
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I am having a problem with the stamp2. All along for expermental
purposes I have been running my stamp off a 6 V battery. Also powering
the servos with the same. I now have built a regulated power supply,
Step down trans, full bridge Rectifier, 4700 uF Cap, and a 5 volt
regulating chip. When I connect it to the stamp and servo, all I get
is the servos shaking. I tried doubling the caps but still no good.
If I also connect the batttery, it works fine. Seems to me that the
caps are not evening out the voltage. I checked the caps, they seem
fine. Any Ideas ???
Donald Brunner
purposes I have been running my stamp off a 6 V battery. Also powering
the servos with the same. I now have built a regulated power supply,
Step down trans, full bridge Rectifier, 4700 uF Cap, and a 5 volt
regulating chip. When I connect it to the stamp and servo, all I get
is the servos shaking. I tried doubling the caps but still no good.
If I also connect the batttery, it works fine. Seems to me that the
caps are not evening out the voltage. I checked the caps, they seem
fine. Any Ideas ???
Donald Brunner
Comments
> I am having a problem with the stamp2. All along for expermental
> purposes I have been running my stamp off a 6 V battery. Also
powering
> the servos with the same. I now have built a regulated power
supply,
> Step down trans, full bridge Rectifier, 4700 uF Cap, and a 5 volt
> regulating chip. When I connect it to the stamp and servo, all I
get
> is the servos shaking. I tried doubling the caps but still no good.
> If I also connect the batttery, it works fine. Seems to me that
the
> caps are not evening out the voltage. I checked the caps, they seem
> fine. Any Ideas ???
>
>
> Donald Brunner
Voltage may not be your problem..whats the current required by all
your loads? Whats the rating of the transformer? Whats the current
rating of the regulator? The regulator could be folding back
Good luck
have to change the power supply pin from 24 to 21, as applying 5 volts to
pin 24(pwr) would not be enough voltage to operate the stamp.
At 01:59 AM 09/30/2000 -0000, you wrote:
>--- In basicstamps@egroups.com, The Brunner Family <drb@c...> wrote:
>> I am having a problem with the stamp2. All along for expermental
>> purposes I have been running my stamp off a 6 V battery. Also
>powering
>> the servos with the same. I now have built a regulated power
>supply,
>> Step down trans, full bridge Rectifier, 4700 uF Cap, and a 5 volt
>> regulating chip. When I connect it to the stamp and servo, all I
>get
>> is the servos shaking. I tried doubling the caps but still no good.
>> If I also connect the batttery, it works fine. Seems to me that
>the
>> caps are not evening out the voltage. I checked the caps, they seem
>> fine. Any Ideas ???
>>
>>
>> Donald Brunner
>
>Voltage may not be your problem..whats the current required by all
>your loads? Whats the rating of the transformer? Whats the current
>rating of the regulator? The regulator could be folding back
>
>Good luck
>
>
>
>
>The transformer is rated at 1.3 amps, the regulator is rated at 1 amp. I
>don't believe the problem is current since I do not see a voltage drop at
>the power input. It reads a steady 5 v
>
>Do servos take 6 v or will they do fine at 5 v. someone told me that the
>servos require 6V.
General R/C Servo Comments:
Usually 4.5 - 6.0 is safe. More "punch" at the higher voltages. It might be
observed in the genearal case that these generally (in the non-robotics
world) operate from batteries; thus the need for a wide permissable voltage
range on R/C boats, and planes.
Various vendors/manufacturers will specify their servos performance at a
particular voltage, That should no way be construed as the maximum or
optimal voltage for any given application. It is important to stay below
the provider's stated maximum, and above the minimum (common sense, and
good practice).
Testing a particular servo, power source, and circuitry with your
particular application will prove what works best for you.
Some applications prefer lowered power, and are willing to sacrifice some
degree of speed. Others require speed, and care less about power. YMMV -
based on your particular needs.
Hope that gives you some overview.
Sorry I have no specific answer for your problem.
Hint: Always make sure the ground path is solid through-out !
Regards,
Bruce Bates
>Jay Kobelin wrote:
>
> > --- In basicstamps@egroups.com, The Brunner Family <drb@c...> wrote:
> > > I am having a problem with the stamp2. All along for expermental
> > > purposes I have been running my stamp off a 6 V battery. Also
> > powering
> > > the servos with the same. I now have built a regulated power
> > supply,
> > > Step down trans, full bridge Rectifier, 4700 uF Cap, and a 5 volt
> > > regulating chip. When I connect it to the stamp and servo, all I
> > get
> > > is the servos shaking. I tried doubling the caps but still no good.
> > > If I also connect the batttery, it works fine. Seems to me that
> > the
> > > caps are not evening out the voltage. I checked the caps, they seem
> > > fine. Any Ideas ???
> > >
> > >
> > > Donald Brunner
> >
> > Voltage may not be your problem..whats the current required by all
> > your loads? Whats the rating of the transformer? Whats the current
> > rating of the regulator? The regulator could be folding back
> >
> > Good luck
don't believe the problem is current since I do not see a voltage drop at
the power input. It reads a steady 5 v
Do servos take 6 v or will they do fine at 5 v. someone told me that the
servos require 6V.
Jay Kobelin wrote:
> --- In basicstamps@egroups.com, The Brunner Family <drb@c...> wrote:
> > I am having a problem with the stamp2. All along for expermental
> > purposes I have been running my stamp off a 6 V battery. Also
> powering
> > the servos with the same. I now have built a regulated power
> supply,
> > Step down trans, full bridge Rectifier, 4700 uF Cap, and a 5 volt
> > regulating chip. When I connect it to the stamp and servo, all I
> get
> > is the servos shaking. I tried doubling the caps but still no good.
> > If I also connect the batttery, it works fine. Seems to me that
> the
> > caps are not evening out the voltage. I checked the caps, they seem
> > fine. Any Ideas ???
> >
> >
> > Donald Brunner
>
> Voltage may not be your problem..whats the current required by all
> your loads? Whats the rating of the transformer? Whats the current
> rating of the regulator? The regulator could be folding back
>
> Good luck
sargent@s... wrote:
> when you switched your stamp power supply from 6 volts to five, you would
> have to change the power supply pin from 24 to 21, as applying 5 volts to
> pin 24(pwr) would not be enough voltage to operate the stamp.
>
>
>
> At 01:59 AM 09/30/2000 -0000, you wrote:
> >--- In basicstamps@egroups.com, The Brunner Family <drb@c...> wrote:
> >> I am having a problem with the stamp2. All along for expermental
> >> purposes I have been running my stamp off a 6 V battery. Also
> >powering
> >> the servos with the same. I now have built a regulated power
> >supply,
> >> Step down trans, full bridge Rectifier, 4700 uF Cap, and a 5 volt
> >> regulating chip. When I connect it to the stamp and servo, all I
> >get
> >> is the servos shaking. I tried doubling the caps but still no good.
> >> If I also connect the batttery, it works fine. Seems to me that
> >the
> >> caps are not evening out the voltage. I checked the caps, they seem
> >> fine. Any Ideas ???
> >>
> >>
> >> Donald Brunner
> >
> >Voltage may not be your problem..whats the current required by all
> >your loads? Whats the rating of the transformer? Whats the current
> >rating of the regulator? The regulator could be folding back
> >
> >Good luck
> >
> >
> >
> >
> Jay, you may have hit the nail on the head with current. I just
tried to
> power up the stamp by itself and wrote a simple program with debug
just to see
> if the stamp itself was running. It did, perfectly. But as soon
as I added
> the servos to the circuit, it went crazy. Current has to be the
problem. I
> checked with a digital meter the current draw, but is only shows
about a 450 mA
> draw. But it might spike up above the one amp so quickly that it
does not show
> on the meter for amps or in voltage drop. I am going to see if I
can build a
> bigger power supply, maybe one just for the Stamp and one just for
the servos,
> bringing both grounds together.
>
> Don
Another problem you may have, as you noted when the servos were
connected, may be noise generated by the servo, getting on the DC and
driving the STAMP nuts. It reminds me of the investigation of the
killing of transistors when relays were first switched with them. The
famous diode across the relay coil thus solved that problem by
circulating the back EMF at the coil, not thru the transistor.
If you play with the power supply voltage and can tweak it a shade
higher (.7v), you may want to try a steering diode (or 2). Keep in
mind you will drop .7v thru each diode. Ensure the diode can handle
the current being pulled.
The digital meter to read current is fine but you're seeing RMS.
You'll never catch surges, peaks or transients with that instrument.
If you have an oscilloscope, use that.
power up the stamp by itself and wrote a simple program with debug just to see
if the stamp itself was running. It did, perfectly. But as soon as I added
the servos to the circuit, it went crazy. Current has to be the problem. I
checked with a digital meter the current draw, but is only shows about a 450 mA
draw. But it might spike up above the one amp so quickly that it does not show
on the meter for amps or in voltage drop. I am going to see if I can build a
bigger power supply, maybe one just for the Stamp and one just for the servos,
bringing both grounds together.
Don