Robot power from two nicads
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Posts: 46,084
Hello all: I have a small robot I am building that uses a stamp II.
I really wanted to stick with 2, C-cell batteries only in the robot, due to
space limitations.
My drive motors were designed for 3 volts, or 2 nicads (2.5V) I only want a
simple forward and reverse for both motors, so bought a Texas Instruments
SN754410NE 1A Dual H-Bridge. This chip worked good when I tested it at 5
Volts, however I see it says it works with 4.5V-36 V and I can't get it to
work at 3V DOH.
I had planned to use a small dc-dc convertor to power the stamp at 5V for
the TTL and a few small sensors. (if I can get it built)
Now I am stuck at deciding what to do, since I need 5V for the Stamp, and
sensor, 2.5-3V for the motors, and want to do it all with only 2 batteries.
The motors draw about 200 Mah/3V each, my Sensor draws 40Mah/5v. the stampII
draws whatever?
If I build a higher amperage DC-DC convertor to supply the H driver chip,
and the stamp and sensors, then I need to turn around and lower the voltage
back down for the 3V motors. Seems like a waste raising voltage, then
lowering it again.
Am I missing something simple here? I thought of a seperate real tiny
battery pack for the stamp and sensor using 4 small AAA cells, but then I
still need an H-bridge for the motors.
I do have a pair of Motor mind B's but really wanted to save them for a
bigger robot, and I only want forward and reverse, no fancy speed changes.
One last question, if I power the sensor (40Mah) directly off the stamp
regulator, am I pushing my luck? I see the stampII can source 50Mah, but I
dont wish to wear it out either.
Thank you to everyone.
Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795
I really wanted to stick with 2, C-cell batteries only in the robot, due to
space limitations.
My drive motors were designed for 3 volts, or 2 nicads (2.5V) I only want a
simple forward and reverse for both motors, so bought a Texas Instruments
SN754410NE 1A Dual H-Bridge. This chip worked good when I tested it at 5
Volts, however I see it says it works with 4.5V-36 V and I can't get it to
work at 3V DOH.
I had planned to use a small dc-dc convertor to power the stamp at 5V for
the TTL and a few small sensors. (if I can get it built)
Now I am stuck at deciding what to do, since I need 5V for the Stamp, and
sensor, 2.5-3V for the motors, and want to do it all with only 2 batteries.
The motors draw about 200 Mah/3V each, my Sensor draws 40Mah/5v. the stampII
draws whatever?
If I build a higher amperage DC-DC convertor to supply the H driver chip,
and the stamp and sensors, then I need to turn around and lower the voltage
back down for the 3V motors. Seems like a waste raising voltage, then
lowering it again.
Am I missing something simple here? I thought of a seperate real tiny
battery pack for the stamp and sensor using 4 small AAA cells, but then I
still need an H-bridge for the motors.
I do have a pair of Motor mind B's but really wanted to save them for a
bigger robot, and I only want forward and reverse, no fancy speed changes.
One last question, if I power the sensor (40Mah) directly off the stamp
regulator, am I pushing my luck? I see the stampII can source 50Mah, but I
dont wish to wear it out either.
Thank you to everyone.
Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795
Comments
the voltage drop across the transisitors would be 1.5 to 2 v leaving about
3V across the motor which is what you need. I used a MOSFET h-brigde
because I wanted to drive 5V motors with a 5V supply (Rds is small and there
isn't much voltage drop across the mosfets.)
> Hello all: I have a small robot I am building that uses a stamp II.
> I really wanted to stick with 2, C-cell batteries only in the robot, due
to
> space limitations.
> My drive motors were designed for 3 volts, or 2 nicads (2.5V) I only want
a
> simple forward and reverse for both motors, so bought a Texas Instruments
> SN754410NE 1A Dual H-Bridge. This chip worked good when I tested it at 5
> Volts, however I see it says it works with 4.5V-36 V and I can't get it to
> work at 3V DOH.
> I had planned to use a small dc-dc convertor to power the stamp at 5V for
> the TTL and a few small sensors. (if I can get it built)
> Now I am stuck at deciding what to do, since I need 5V for the Stamp, and
> sensor, 2.5-3V for the motors, and want to do it all with only 2
batteries.
> The motors draw about 200 Mah/3V each, my Sensor draws 40Mah/5v. the
stampII
> draws whatever?
> If I build a higher amperage DC-DC convertor to supply the H driver chip,
> and the stamp and sensors, then I need to turn around and lower the
voltage
> back down for the 3V motors. Seems like a waste raising voltage, then
> lowering it again.
> Am I missing something simple here? I thought of a seperate real tiny
> battery pack for the stamp and sensor using 4 small AAA cells, but then I
> still need an H-bridge for the motors.
> I do have a pair of Motor mind B's but really wanted to save them for a
> bigger robot, and I only want forward and reverse, no fancy speed changes.
> One last question, if I power the sensor (40Mah) directly off the stamp
> regulator, am I pushing my luck? I see the stampII can source 50Mah, but I
> dont wish to wear it out either.
> Thank you to everyone.
>
>
>
> Sincerely
> Kerry
> Admin@M...
> WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> Kerry Barlow
> p.o. box 21
> kirkwood ny
> 13795
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
Have ever seen a voltage doubler? Diode and cap combo. might do the trick as
long the current is low.
Brian
Original Message
From: "Kerry Barlow" <admin@m...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, April 10, 2001 12:22 PM
Subject: [noparse][[/noparse]basicstamps] Robot power from two nicads
> Hello all: I have a small robot I am building that uses a stamp II.
> I really wanted to stick with 2, C-cell batteries only in the robot, due
to
> space limitations.
> My drive motors were designed for 3 volts, or 2 nicads (2.5V) I only want
a
> simple forward and reverse for both motors, so bought a Texas Instruments
> SN754410NE 1A Dual H-Bridge. This chip worked good when I tested it at 5
> Volts, however I see it says it works with 4.5V-36 V and I can't get it to
> work at 3V DOH.
> I had planned to use a small dc-dc convertor to power the stamp at 5V for
> the TTL and a few small sensors. (if I can get it built)
> Now I am stuck at deciding what to do, since I need 5V for the Stamp, and
> sensor, 2.5-3V for the motors, and want to do it all with only 2
batteries.
> The motors draw about 200 Mah/3V each, my Sensor draws 40Mah/5v. the
stampII
> draws whatever?
> If I build a higher amperage DC-DC convertor to supply the H driver chip,
> and the stamp and sensors, then I need to turn around and lower the
voltage
> back down for the 3V motors. Seems like a waste raising voltage, then
> lowering it again.
> Am I missing something simple here? I thought of a seperate real tiny
> battery pack for the stamp and sensor using 4 small AAA cells, but then I
> still need an H-bridge for the motors.
> I do have a pair of Motor mind B's but really wanted to save them for a
> bigger robot, and I only want forward and reverse, no fancy speed changes.
> One last question, if I power the sensor (40Mah) directly off the stamp
> regulator, am I pushing my luck? I see the stampII can source 50Mah, but I
> dont wish to wear it out either.
> Thank you to everyone.
>
>
>
> Sincerely
> Kerry
> Admin@M...
> WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> Kerry Barlow
> p.o. box 21
> kirkwood ny
> 13795
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
Shop online without a credit card
http://www.rocketcash.com
RocketCash, a NetZero subsidiary
doubler. Not very practical here. Typically this is done from within the
H-bridge package.
Original Message
> Have ever seen a voltage doubler? Diode and cap combo. might do the trick
as
> long the current is low.
> > Hello all: I have a small robot I am building that uses a stamp II.
> > I really wanted to stick with 2, C-cell batteries only in the robot, due
> to
> > space limitations.
of a 3V to 5V stepup converter on the LT111 page.
www.linear-tech.com/prod/datasheet.html?datasheet=303
Rodent wrote:
>
> Only works with AC. You would need some sort of oscillator to drive the
> doubler. Not very practical here. Typically this is done from within the
> H-bridge package.
>
>
Original Message
>
> > Have ever seen a voltage doubler? Diode and cap combo. might do the trick
> as
> > long the current is low.
>
> > > Hello all: I have a small robot I am building that uses a stamp II.
> > > I really wanted to stick with 2, C-cell batteries only in the robot, due
> > to
> > > space limitations.
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Original Message
From: Rodent <daweasel@s...>
Date: Tuesday, April 10, 2001 6:52 pm
Subject: Re: [noparse][[/noparse]basicstamps] Robot power from two nicads
> Only works with AC. You would need some sort of oscillator to
> drive the
> doubler. Not very practical here. Typically this is done from
> within the
> H-bridge package.
>
>
Original Message
>
> > Have ever seen a voltage doubler? Diode and cap combo. might do
> the trick
> as
> > long the current is low.
>
> > > Hello all: I have a small robot I am building that uses a
> stamp II.
> > > I really wanted to stick with 2, C-cell batteries only in the
> robot, due
> > to
> > > space limitations.
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>