controlling voltage in outputs?
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This may be a dumb question...My school just purchased a BS2p40. It
takes, or it is recommended, that a 7.5 dc line in be used for
power. If you have motors, lcds, whatever on the output side that
require something different than 7.5 volts, say something less or
even more, how do you tell the bs2p40 what voltage to output and
then to what 1/0's? Besides this, does anyone know if accessories
from makingthings.com are compatible with the bs2p40...for some
reason we have a whole bunch of gizmos from that site delivered to
us. thanks for the help. mark
takes, or it is recommended, that a 7.5 dc line in be used for
power. If you have motors, lcds, whatever on the output side that
require something different than 7.5 volts, say something less or
even more, how do you tell the bs2p40 what voltage to output and
then to what 1/0's? Besides this, does anyone know if accessories
from makingthings.com are compatible with the bs2p40...for some
reason we have a whole bunch of gizmos from that site delivered to
us. thanks for the help. mark
Comments
<markmcleod50@y...> wrote:
> This may be a dumb question...My school just purchased a BS2p40. It
> takes, or it is recommended, that a 7.5 dc line in be used for
> power. If you have motors, lcds, whatever on the output side that
> require something different than 7.5 volts, say something less or
> even more, how do you tell the bs2p40 what voltage to output and
> then to what 1/0's? Besides this, does anyone know if accessories
> from makingthings.com are compatible with the bs2p40...for some
> reason we have a whole bunch of gizmos from that site delivered to
> us. thanks for the help. mark
Hi Mark,
The 'control logic' power is 5 volts. period.
you can send a signal out to a darlington transistor like a PN2222
and that will act like a switch.
the 2222 can have 20 volts in on the collector and power your 20 volt
motor. But, on the base, the control input line, it only needs 5
volts.
a MOSFET, around a buck, might be rated for 200 volts, 20 amps, but
switch on and off from your 5 volt control signal.
Similarly, an electromechanical relay may operate with 5 volts, but
the input and output 'power' lines might be 460 volts AC.
As you will quickly find out, you are limited to the power output or
current output of each pin and the whole chip. Actually the whole
chip is less than the mathematical total of all the pins.
But by using external chips, you can do the same thing we do every
night Pinky. Try to take over the world!
Dave
wrote:
> --- In basicstamps@yahoogroups.com, "sponsitility"
> <markmcleod50@y...> wrote:
> > This may be a dumb question...My school just purchased a BS2p40.
It
> > takes, or it is recommended, that a 7.5 dc line in be used for
> > power. If you have motors, lcds, whatever on the output side that
> > require something different than 7.5 volts, say something less or
> > even more, how do you tell the bs2p40 what voltage to output and
> > then to what 1/0's? Besides this, does anyone know if
accessories
> > from makingthings.com are compatible with the bs2p40...for some
> > reason we have a whole bunch of gizmos from that site delivered
to
> > us. thanks for the help. mark
>
>
> Hi Mark,
>
> The 'control logic' power is 5 volts. period.
>
> you can send a signal out to a darlington transistor like a PN2222
> and that will act like a switch.
>
> the 2222 can have 20 volts in on the collector and power your 20
volt
> motor. But, on the base, the control input line, it only needs 5
> volts.
>
> a MOSFET, around a buck, might be rated for 200 volts, 20 amps, but
> switch on and off from your 5 volt control signal.
>
> Similarly, an electromechanical relay may operate with 5 volts, but
> the input and output 'power' lines might be 460 volts AC.
>
> As you will quickly find out, you are limited to the power output
or
> current output of each pin and the whole chip. Actually the whole
> chip is less than the mathematical total of all the pins.
>
> But by using external chips, you can do the same thing we do every
> night Pinky. Try to take over the world!
>
> Dave
Pinky, are you thinking what I'm thinking?
"I think so, Brain, but where are we going to
get rubber pants in our size?"
wrote:
> --- In basicstamps@yahoogroups.com, "Dave Mucha" <davemucha@j...>
> wrote:
> > --- In basicstamps@yahoogroups.com, "sponsitility"
> > <markmcleod50@y...> wrote:
> > > This may be a dumb question...My school just purchased a
BS2p40.
> It
> > > takes, or it is recommended, that a 7.5 dc line in be used for
> > > power. If you have motors, lcds, whatever on the output side
that
> > > require something different than 7.5 volts, say something less
or
> > > even more, how do you tell the bs2p40 what voltage to output
and
> > > then to what 1/0's? Besides this, does anyone know if
> accessories
> > > from makingthings.com are compatible with the bs2p40...for some
> > > reason we have a whole bunch of gizmos from that site delivered
> to
> > > us. thanks for the help. mark
> >
> >
> > Hi Mark,
> >
> > The 'control logic' power is 5 volts. period.
> >
> > you can send a signal out to a darlington transistor like a
PN2222
> > and that will act like a switch.
> >
> > the 2222 can have 20 volts in on the collector and power your 20
> volt
> > motor. But, on the base, the control input line, it only needs 5
> > volts.
> >
> > a MOSFET, around a buck, might be rated for 200 volts, 20 amps,
but
> > switch on and off from your 5 volt control signal.
> >
> > Similarly, an electromechanical relay may operate with 5 volts,
but
> > the input and output 'power' lines might be 460 volts AC.
> >
> > As you will quickly find out, you are limited to the power output
> or
> > current output of each pin and the whole chip. Actually the whole
> > chip is less than the mathematical total of all the pins.
> >
> > But by using external chips, you can do the same thing we do
every
> > night Pinky. Try to take over the world!
> >
> > Dave
>
> Pinky, are you thinking what I'm thinking?
>
> "I think so, Brain, but where are we going to
> get rubber pants in our size?"
I realized I didn't go the other way.
If you need to send a really fast pulse, you might set up a single
shot pulse circuit and with a single output signal, it can make that
circuit send that pulse.
or, if you want to send an ultral low value that is contorlled, you
might signal an op-amp and that will output the low value.
And the 4066 chip is an analog switch. you can switch analogue
values to another device without inteferring with the signal.
So, just like your finger and and a wall light switch, the Stamp
output does not touch the power in the circuit, but is only the
signal.
Dave
Pinky, Are You Pondering What I'm Pondering?
Well, I think so Brain but if Jimmy cracks corn and no one cares, why
does he keep doing it?
> takes, or it is recommended, that a 7.5 dc line in be used for
> power. If you have motors, lcds, whatever on the output side that
> require something different than 7.5 volts, say something less or
> even more, how do you tell the bs2p40 what voltage to output and
> then to what 1/0's?
None of the BS2's can adjust the voltage out of the on chip regulator. Most
motors and LED's can run off of the unregulated (7.5V DC) power but their
connection to that power has to be controlled by the BS2. Depending on the
amount of current require this can be a direct connect (LED? less than 20
mA), thru a small transistor wo/heatsink (LED arrays or smallest motors,
usually 1/4 amp or less). A larger transistor with a head sink (up to 1 amp
motors). Power FET's, Darlington pairs, H-Bridges, etc. (Larger motors) or
relays (A/C motors).
The BS2 can only output a binary (0/1, yes/no) output. This can be used to
turn LED's, motors, etc. on/off. It can also use Pulse Width Modulation
(PWM) to control the speed of a motor or brightness of an LED. This works by
toggling the output control pin on/off at a ratio that corresponds to the
speed/brightness. For example, if you want a LED lit at 90% brightness then
the PWM output cycles between on 90% of the time and off 10% of the time. It
does the very fast (thousands of times a second) so that you don't see it
turning on and off. The LED is just percieved to be 10% dimmer.
Another form of PWM is servo control. A servo uses the phase of the PWM
signal to tell the motor to what position to drive the servo. (This a bit of
an oversimplification, but it's essentially true. ;-)
> Besides this, does anyone know if accessories
> from makingthings.com are compatible with the bs2p40...for some
> reason we have a whole bunch of gizmos from that site delivered to
> us.
The main telco board talks to a PeeCee via USB. As far as I know none of the
BS2's will talk USB. The main board talks to all the other boards via a 250
kb/s RS-485 connection. While you can probably wire up a BS2 to do RS-485 I
don't think any of the BS2's can handle 250 kb/s.
--
Enjoy,
George Warner,
Schizophrenic Optimization Scientists
Apple Developer Technical Support (DTS)