controlling a DC motor AND a servo with 4 wires?
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I want to use my Stamp to control a small model car, tethered to the
stamp with a phone cord. I am limited to using a phone cord, because
I am using a telephone detangler as a slip-ring to compensate for the
cord twisting up. Therefore, I have four wires to work with.
Wires #1 and #2 will drive the DC motor in the rear wheels, both
forwards and backwards, using an H-Bridge. The steering will be
accomplished with a micro servo hooked to the front wheels. Wire #3
will provide the servo with a dedicated 5V, and wire #4 will provide
the servo signal. My problem is how to connect the servo to ground.
Since the polarity on the motor wires will reverse depending on the
direction of travel, ground could be either wire #1 or #2. I had
considered hooking on to wires #1 and #2, running each through
diodes, and running them BOTH to the ground terminal of the servo,
which would ensure that the current to the DC motor will never flow
into the ground terminal of the servo.
Can anyone see a problem with this, or does it sound like it will
work? Any better ideas would be welcomed!
Thanks in advance,
--alex
stamp with a phone cord. I am limited to using a phone cord, because
I am using a telephone detangler as a slip-ring to compensate for the
cord twisting up. Therefore, I have four wires to work with.
Wires #1 and #2 will drive the DC motor in the rear wheels, both
forwards and backwards, using an H-Bridge. The steering will be
accomplished with a micro servo hooked to the front wheels. Wire #3
will provide the servo with a dedicated 5V, and wire #4 will provide
the servo signal. My problem is how to connect the servo to ground.
Since the polarity on the motor wires will reverse depending on the
direction of travel, ground could be either wire #1 or #2. I had
considered hooking on to wires #1 and #2, running each through
diodes, and running them BOTH to the ground terminal of the servo,
which would ensure that the current to the DC motor will never flow
into the ground terminal of the servo.
Can anyone see a problem with this, or does it sound like it will
work? Any better ideas would be welcomed!
Thanks in advance,
--alex
Comments
I did almost exactly what you are speaking of (not wired, but limited by
the number of channels on a rc setup) and it worked just fine. YMMV
-John
Original Message
From: robot_geek1138 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=N5Iws2XwrpOfKiY1Z4elfLMA3LZnwLZ5oavmacZxQLZVmSAwM-fku8yjHZnw32h3Sa8Y6OBQLxWN3xZCpQk]robot_geek1138@y...[/url
Sent: Friday, January 02, 2004 9:43 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] controlling a DC motor AND a servo with 4 wires?
I want to use my Stamp to control a small model car, tethered to the
stamp with a phone cord. I am limited to using a phone cord, because
I am using a telephone detangler as a slip-ring to compensate for the
cord twisting up. Therefore, I have four wires to work with.
Wires #1 and #2 will drive the DC motor in the rear wheels, both
forwards and backwards, using an H-Bridge. The steering will be
accomplished with a micro servo hooked to the front wheels. Wire #3
will provide the servo with a dedicated 5V, and wire #4 will provide
the servo signal. My problem is how to connect the servo to ground.
Since the polarity on the motor wires will reverse depending on the
direction of travel, ground could be either wire #1 or #2. I had
considered hooking on to wires #1 and #2, running each through
diodes, and running them BOTH to the ground terminal of the servo,
which would ensure that the current to the DC motor will never flow
into the ground terminal of the servo.
Can anyone see a problem with this, or does it sound like it will
work? Any better ideas would be welcomed!
Thanks in advance,
--alex
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mini motor controller; then you get this:
1 - Power
2 - Ground
3 - Serial Signal to MMC
4 - Servo pulse
-- Jon Williams
-- Parallax
Original Message
From: robot_geek1138 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=rFPf1qYNoXFravDx4B2X7V9Ul6Sm32Fqq1JVO-SadQW-g24pI1MEROl6viPCNdMErMhWo1l9jzTnoUbn19L13gnS-Q]robot_geek1138@y...[/url
Sent: Friday, January 02, 2004 9:43 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] controlling a DC motor AND a servo with 4 wires?
I want to use my Stamp to control a small model car, tethered to the
stamp with a phone cord. I am limited to using a phone cord, because
I am using a telephone detangler as a slip-ring to compensate for the
cord twisting up. Therefore, I have four wires to work with.
Wires #1 and #2 will drive the DC motor in the rear wheels, both
forwards and backwards, using an H-Bridge. The steering will be
accomplished with a micro servo hooked to the front wheels. Wire #3
will provide the servo with a dedicated 5V, and wire #4 will provide
the servo signal. My problem is how to connect the servo to ground.
Since the polarity on the motor wires will reverse depending on the
direction of travel, ground could be either wire #1 or #2. I had
considered hooking on to wires #1 and #2, running each through
diodes, and running them BOTH to the ground terminal of the servo,
which would ensure that the current to the DC motor will never flow
into the ground terminal of the servo.
Can anyone see a problem with this, or does it sound like it will
work? Any better ideas would be welcomed!
Thanks in advance,
--alex
To UNSUBSCRIBE, just send mail to:
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and Body of the message will be ignored.
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