oSpeedOMeter Object

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Description
Operation
Properties

Examples
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Description:

An Object that reads a Speedometer.

The following table lists the size and availability of the oSpeedOMeter Object.

	Object	Size	Description	A1	A2	B1	B2	C1
	oSpeedOMeter	6 Bytes	Reads a Speedometer.			x	x	x

Operation:

The oSpeedOMeter Object handles all the necessary I/O timing requirements to read a speedometer.

The oSpeedOMeter Object monitors the I/O line specified by IOLine property. As long as the Operate property is 1, the oSpeedOMeter Object will continually update its Speed property. The Speed property is updated each time a new high-going pulse is received from the Speedometer.

When the speedometer's axel is turning, the Speed property is set to a value from 1 to 255 which indicates the Speed and the Turning property is set to 1. As the rate of turn increases, the value of the Speed property increases. When the Speedometer's axel is not turning, or is turning at less than 1 round per second, the Speed and the Turning properties will be set to 0.

The Speed property is calculated from the following formula: Speed = (256 - (283 / RevolutionsPerSecond))
Inversely, the Revolutions-Per-Second can be calculated from the Speed: RevolutionsPerSecond = (283 / (256-Speed))

Note that the Speed is not linear. As the Revolutions-Per-Second goes up, the Speed property increases at a quicker rate. Thusly, while the the oSpeedOMeter Object is capable of measuring up to 283 Revolutions-Per-Second, it is best at measuring less than 5 Revolutions-Per-Second. (See Speed property table)

The Timer property is an instance of the oCycleTimeL object which is created when the oSpeedOMeter Object is. The oSpeedOMeter Object uses the timer object to read the signal generated by the Speedometer. Modifying any of the properties of the oCycleTimeL instance will affect the oSpeedOMeter Object's operation. See the oCycleTimeL Help for more detail on how the oSpeedOMeter reads the Speedometer's signal.

Properties:

The following table lists the properties of the oSpeedOMeter Object:

Property
Description

Speed

A value that indicates the Speed that the speedometer's axel is turning.

Object Class: oByte Value Range: 0 - 255

Data Type: Numeric Default Value: 0

The Speed is determined using the following formula: Speed = [256 - (283 / RevolutionsPerSecond)

Speed Description

0 The axel is turning slower than 1.1 revolution per second.

1 The axel is turning 1.105 revolutions per second.

2 The axel is turning 1.110 revolutions per second.

3-252 The axel is turning between 1.110 and 93.33 revolutions per second.

253 The axel is turning 93.33 revolutions per second.

254 The axel is turning 141 revolutions per second.

255 The axel is turning 383 revolution per second or faster.

Turning

A value that indicates that the speedometer's axel is turning.

Object Class: oLogic Value Range: 0 - 1

Data Type: Numeric Default Value: 0

Operate Constant Description

0 cvFalse The axel is not turning.

1 cvTrue The axel is turning.

IOLine

A value that specifies which I/O Line is connected to the Speedometer.

Object Class: oIOLine Value Range: 0 - 31

Data Type: Numeric Default Value: 0

Some I/O Lines have special purposes. Be sure to see oIOLine help file for details.

Operate

A value that selects whether or not the Speedometer is being read.

Object Class: oOperate Value Range: 0 - 1

Data Type: Numeric Default Value: 0

Operate Constant Description

0 cvOff The properties are not updated.

1 cvOn The properties are updated.

Timer

The I/O function object used to read the Speedometer.

Object Class: oCycleTimeL Value Range: 0 - 255

Data Type: Numeric Default Value: 0

Address

Returns a pointer to the address of the oCounter Object instance.

Object Class: oAddress Value Range: 0 - 127

Data Type: Pointer (Read Only) Default Value: Address of Object

Examples:

In the following example, the oSpeedOMeter Object is used.

Visual Basic Syntax

C and Java Syntax

'This program reads how fast 
'an axel is turning with an  
'oSpeedOMeter Object and 
'outputs the value as a tone

Dim A As New oSpeedOMeter
Dim B As New oSpeaker
Dim C As New oDIO1

Sub Main()
  A.IOLine = 15
  A.Operate = cvTrue
  B.Operate = 1
  C.IOLine = 8
  C.Direction = cvOutput
  Do
    B.Tone = A.Speed * 250
    C.State = A.Turning
  Loop
End Sub

//This program reads how fast 
//an axel is turning with an  
//oSpeedOMeter Object and 
//outputs the value as a tone

oSpeedOMeter A = New oSpeedOMeter;
oSpeaker B = New oSpeaker;
oDIO1 C = New oDIO1;

Void Main(Void){
  A.IOLine = 15;
  A.Operate = cvTrue;
  B.Operate = 1;
  C.IOLine = 8;
  C.Direction = cvOutput;
  Do{
    B.Tone = A.Speed * 250;
    C.State = A.Turning;
  } While (1)
}

Basic Syntax

'This program reads how fast 
'an axel is turning with an  
'oSpeedOMeter Object and 
'outputs the value as a tone

A As oSpeedOMeter
B As oSpeaker(0,cvOn)
C As oDIO1(8,cvOutput)

A.IOLine = 15
A.Operate = cvTrue

Do
  B.Tone = A.Speed * 250
  C.State = A.Turning
Loop

Connections:

The oSpeedOMeter uses the single I/O line specified by the IOLine property. The I/O line can be any 1 I/O line of the ooPIC's 31 I/O lines as long as it is not being used by another function. As shown, a magnetic reed switch is used in conjunction with a rotating axel with a magnet mounted on one side. Each time the axel rotates one revolution, the reed switch will close, and the oSpeedOMeter will calculate a new Speed value.

Note that a rotational speed of less than once per second will result in a Speed value of 0. If the wheel is revolving at less than this speed, the sensor needs to be mounted somewhere in the gearing or multiple magnets need to be used.