| DC motors can be controlled from the OOPic in a
variety of ways utilizing everything from relays to power
mosfets. This project shows how to configure two oPWMs and some oDIO1
Objects into a Virtual Circuit
that will control the speed of two DC motors. with simple
commands like M1Speed = 10 for a
slow speed, M1Speed = 255 for
full speed, and even M1Brakes = cvOn
to slam on the brakes! This Virtual
Circuit will be created for use with 2 LMD18200
H-Bridge ICs. These H-Bridges are capable of driving
a motor with a voltage range of 10V-DC to 55V-DC with up
to 3A continuous. It can drive the motor at a variable
speed and reversible direction. It also has current
sensing and thermal overload protection.
Several different Objects
can be configured into the Virtual
Circuit to change its behavior, including Thermal
overload detection and current sensing, but for this
project, we will use just speed control, direction and
brakes.
 This little robot base is the
project platform. It has two DC motors turning
two wheels, some batteries, an OOPic and the
project board with the 2 H-bridges.A circuit
board that holds the two LMD18200 IC can be found
at Magnevation
Magnevation also publishes the schematic
for this item.
The pin out of the LMD18200 IC is show below:
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| LMD18200
IC |
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The
Program
Dim M1Speed as new oPWM
Dim M2Speed as new oPWM
Dim M1Brakes as new oDio1
Dim M2Brakes as new oDio1
Dim M1Direction as new oDio1
Dim M2Direction as new oDio1
Dim x as new oByte
Sub Main()
Call SetUp
M1Brakes = cvOff
M2Brakes = cvOff
Do
' This will speed up the two motors
for x = 1 to 254
M1Speed = x
M2Speed = x
next x
' This will slow down the two motors
for x = 254 to 1 step -1
M1Speed = x
M2Speed = x
next x
Loop
End Sub
Sub SetUp()
M1Speed.IOLine = 17
M1Speed.Operate = cvTrue
M2Speed.IOLine = 18
M2Speed.Operate = cvTrue
M1Brakes.IOLine = 24
M1Brakes.Direction = cvOutput
M2Brakes.IOLine = 25
M2Brakes.Direction = cvOutput
M1Direction.IOLine = 26
M1Direction.Direction = cvOutput
M2Direction.IOLine = 27
M2Direction.Direction = cvOutput
End Sub
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Dual DC Motor Control
