Motor Controller and Speed Control

Archiver

Hello,

I have this situation:

I need to build the circuit for controlling 6-12V motors
I am aware of how to build an H-Bridge using transistors as long as I
find the right ones to handle current and the voltage.

Problem is that I need to control the SPEED of the motors using a
connection from the model R/C unit I have. The receiver of course has
the connections for the servos. The motor control circuit can be
easily designed to handle PWM, BUT can the connections meant for the
servo deliver PWM and work exactly like a PIC or stamp to control the
motors and provide SPEED control. Model Control Devices in Ontario
provides motor controllers with speed but I am interested in building
my own. All references to motor control talk about PIC and stamps but
I need to use my transmitter with the two joysticks much like
controlling a tank. One channel/line for forward and reverse and one
channel for speed (One joystick). Schematics or a link would be
great. A lot of sites also refer to speed control through POTs and if
this can be used, I can just connect the servos and move the POTs but
electronic control is prefered over this.

My motors are 6V but I am unaware of the current needs. This is for a
robotics project and the two motors need to move approximately 50-60
lbs.

Thanks

Gary

Archiver

At 9/25/2000 +0000 05:02 AM, you wrote:
>Hello,
>
>I have this situation:
>
>I need to build the circuit for controlling 6-12V motors
>I am aware of how to build an H-Bridge using transistors as long as I
>find the right ones to handle current and the voltage.
>
>Problem is that I need to control the SPEED of the motors using a
>connection from the model R/C unit I have. The receiver of course has
>the connections for the servos. The motor control circuit can be
>easily designed to handle PWM, BUT can the connections meant for the
>servo deliver PWM and work exactly like a PIC or stamp to control the
>motors and provide SPEED control. Model Control Devices in Ontario
>provides motor controllers with speed but I am interested in building
>my own. All references to motor control talk about PIC and stamps but
>I need to use my transmitter with the two joysticks much like
>controlling a tank. One channel/line for forward and reverse and one
>channel for speed (One joystick). Schematics or a link would be
>great. A lot of sites also refer to speed control through POTs and if
>this can be used, I can just connect the servos and move the POTs but
>electronic control is prefered over this.
>
>My motors are 6V but I am unaware of the current needs. This is for a
>robotics project and the two motors need to move approximately 50-60
>lbs.
>
>Thanks
>
>Gary

Gary -

I realize you have 6 volt motors, and, in the end, you will find that to be
a MAJOR problem; at least I did. Most larger platforms are using 24 VDC
(and UP) motors today. That's why the 6 VDC motors are often so cheap (no
reflection on yours). Rather than re-invent the wheel, you might want to
look at a manufactured unit, but one which is surplus, and reasonably
priced ($40.00).

There are still some 12-volts units available BUT at a MUCH higher price.

Check these units:

http://members.tripod.com/~divelec/hbridge.html

While YOU are there, check the MCB interface, and all the Applications
notes. They will show, in great detail, all the things you can do with this
VERSATILE board. The interfacing is DIRECTLY from a Stamp or a PIC, with
PWM and ramp-up/down included on some of them. RF control is shown as well.

I have NO connection with Carl, except to say I am a VERY satisfied
customer, and I Beta tested his most recent products that he manufactures
himself. TOP quality and a FAIR PRICE - what more can I say.

Hope that shows whats available today in the MCB marketplace, and what
options may be availalble, if you choose the non-DIY route.

Regards,

Bruce Bates
.

Archiver

Hi Gary,

Please see my web pages at http://members.tripod.com/~divelec/r3rcjs01.html
and http://members.tripod.com/~divelec/pwm1mtr.html and
http://members.tripod.com/~divelec/pwm2mtr.html .

Hope this info will help you.

Carl
Diverse Electronic Services

---

Original Message

---

From: Gary Companion <gcompanion@h...>
To: <basicstamps@egroups.com>
Sent: Monday, September 25, 2000 1:02 AM
Subject: [noparse][[/noparse]basicstamps] Motor Controller and Speed Control


> Hello,
>
> I have this situation:
>
> I need to build the circuit for controlling 6-12V motors
> I am aware of how to build an H-Bridge using transistors as long as I
> find the right ones to handle current and the voltage.
>
> Problem is that I need to control the SPEED of the motors using a
> connection from the model R/C unit I have. The receiver of course has
> the connections for the servos. The motor control circuit can be
> easily designed to handle PWM, BUT can the connections meant for the
> servo deliver PWM and work exactly like a PIC or stamp to control the
> motors and provide SPEED control. Model Control Devices in Ontario
> provides motor controllers with speed but I am interested in building
> my own. All references to motor control talk about PIC and stamps but
> I need to use my transmitter with the two joysticks much like
> controlling a tank. One channel/line for forward and reverse and one
> channel for speed (One joystick). Schematics or a link would be
> great. A lot of sites also refer to speed control through POTs and if
> this can be used, I can just connect the servos and move the POTs but
> electronic control is prefered over this.
>
> My motors are 6V but I am unaware of the current needs. This is for a
> robotics project and the two motors need to move approximately 50-60
> lbs.
>
> Thanks
>
> Gary
>
>
>
>
>
>