LEGO MINDSTORMS Robots User Manual (English)

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only upload fifty datalog values at a time. If you have larger datalog, it must be uploaded in pieces.

The relevant Spirit.ocx function is UploadDatalog, which takes a starting index and a length. The first (zero-th) item of the datalog contains the length of the datalog. It's the first thing

SaveDatalog reads:

data = .UploadDatalog(0, 1)

length = data(2, 0) -1

The actual data length is one less than the reported length, because the zeroth item is not a data point.

The data returned from UploadDatalog is an array. Each datalog item is represented by three numbers. The first two numbers indicate the source and number of the value; source and number

have exactly the same meaning here as they do for Poll. The third number is the actual value stored in the datalog.

SaveDatalog writes the source, number, and value for each datalog item out to a text file. Each line of the text file represents one item from the datalog. On each line, the source, number, and

value of the item are separated by commas. This example interprets the source of each value, then converts it to a descriptive string before writing it out to the file. The output file will look

something like this (depending, of course, on the contents of the datalog):

Variable, 1, 2

Timer, 0, 543

Variable, 2, 8

Variable, 8, 368

Sensor value, 1, 33

Watch, 0, 7

A plain text file of comma-separated values is usually pretty easy to import into a spreadsheet or statistical analysis program. You can use your robot to gather data, use this example program to

upload it to your PC, and then use some other program to analyze or graph the data. Some people have built optical scanners based on RIS using these techniques.

The example is comprised of three parts. The SaveDatalog subroutine does most of the work. It uses the min function to calculate a minimum and the getTypeString function to convert

the datalog item source number to a descriptive string:

Sub SaveDatalog(filname As String)

Dim data As Variant

Dim index, length, stepSize As Integer

Dim line As String

With DummySpiritForm.Spirit1

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' Open the output file.

out = FreeFile

open filename For Output As #out

.InitComm

' First get item zero, which describes the length of the datalog.

data = .UploadDatalog(0, 1)

length = data(2, 0) - 1

' Now upload 50 items at a time.

index = 0

While (index < length)

' Find the smaller of the remaining items or 50.

stepSize = min(length - index, 50)

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LEGO MINDSTORMS Robots Specifications

General

Product Line	LEGO MINDSTORMS
Category	Toy
Age Range	10+
Batteries Required	Yes
Memory	64 MB RAM, 16 MB Flash
Connectivity	Bluetooth, USB
Sensors	Touch, Color, Gyro
Battery Type	AA
Interactive Features	Programmable, Remote Control
App Compatibility	iOS, Android
Processor	ARM9
Pieces Count	601
Battery Count	6
App Name	LEGO MINDSTORMS EV3 Programmer App