Total Robots - Example - BX-24 Servo Control

BX-24 Servo Control

This application demonstrates how the DS-SXM16S Servo Control Module can be controlled by a BX-24 microcontroller, plugged into its onboard Controller Socket.

The BX-24 can be programmed while on board the DS-SXM16S by way of the programming header and programming cable.

This project shows how to control two Hitec HS-300 servomotors connected to the pan and tilt mechanism. On start-up the two servos move to their start positions. The tilt servo will then move up and down, followed by the pan servo moving right then left. The program then loops, continuously repeating the above mentioned servo movements.

The Tilt servo should be connected to the SV1 header.

The Pan servo should be connected to the SV2 header.

'***************************************************************************
'***************************************************************************
' Description: This application demonstrates how the DS-SXM16S servo expansion
' module can use a 24 pin BX-24 to control the servos from the on board micro
' controller socket. The BX24 can also be programmed on the board via the
' programming cable.
'
' Created: 09/01/03 Revision 1.0
' Written by: Total Robots (Jamie Finnan)
' Adapted from Netmedia Hobby Servo Example program.
'
'***************************************************************************
'***************************************************************************
Sub Main()
' This program exercises a servo by moving it back and forth through its
' position range, at about 1 cycle every 5 seconds.
Const ServoPin1 As Byte = 5 ‘Servo on SV1
Const ServoPin2 As Byte = 6 ‘Servo on SV2
Const NSteps As Integer = 100

' This is to generate a refresh rate of roughly 50 Hz.
Const RefreshPeriod As Single = 0.02
Dim i As Integer, Position As Single

Call PulseOut(ServoPin1,0.0015,1) ‘Start Positions for servo1
Call Delay(0.02)
Call PulseOut(ServoPin2,0.0015,1) ‘Start position for servo2
Call Delay(0.02)
Do
' Tilt down
For i = 40 To NSteps
' Nondimensionalize position.
Position = CSng(i) / CSng(NSteps)
Call MoveServo1(ServoPin1, Position)

Call Delay(RefreshPeriod)
Next
' Tilt Up.
For i = NSteps To 40 Step -1
' Nondimensionalize position.
Position = CSng(i) / CSng(NSteps)
Call MoveServo1(ServoPin1, Position)

Call Delay(RefreshPeriod)
Next

' Pan right
For i = 40 To NSteps
' Nondimensionalize position.
Position = CSng(i) / CSng(NSteps)
Call MoveServo2(ServoPin2, Position)

Call Delay(RefreshPeriod)
Next
' Pan Left.
For i = NSteps To 40 Step -1
' Nondimensionalize position.
Position = CSng(i) / CSng(NSteps)
Call MoveServo2(ServoPin2, Position)

Call Delay(RefreshPeriod)
Next Loop
End Sub
'***************************************************************************
Public Sub MoveServo1( _
ByVal ServoPin1 As Byte, _
ByVal Position As Single)
' Moves servo1 by sending a single pulse. The position is a nondimensional
' value in range 0.0 to 1.0.
Dim PulseWidth As Single
' Translate position to pulse width. Resulting range is 1.0 to 2.0 ms,
' centered at 1.5 ms.
PulseWidth = 0.001 + (0.001 * Position)
' Generate a high-going pulse on the servo pin.
Call PulseOut(ServoPin1, PulseWidth, 1)

End Sub
'***************************************************************************
Public Sub MoveServo2( _
ByVal ServoPin2 As Byte, _
ByVal Position As Single)
' Moves servo2 by sending a single pulse. The position is a nondimensional
' value in range 0.0 to 1.0.
Dim PulseWidth As Single
' Translate position to pulse width. Resulting range is 1.0 to 2.0 ms,
' centered at 1.5 ms.
PulseWidth = 0.001 + (0.001 * Position)
' Generate a high-going pulse on the servo pin.
Call PulseOut(ServoPin2, PulseWidth, 1)

End Sub
'***************************************************************************
'***************************************************************************

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