Programming WebBrick

Developing your own WebBrick site

Getting started with the Simple programs

WebBrick comes with some simple programs that you can install in program slots 1-5.

Slot 1: Run motor A backward for 5 seconds
Slot 2: Run motor A forward for 5 seconds
Slot 3: Run motor B backward for 5 seconds
Slot 4: Run motor B forward for 5 seconds
Slot 5: Beep, then run motor C forward for 50 seconds

Turn on your brick and place it near the IR tower. It is easiest to start with a set of programs included with WebBrick. You can download these from the menu, but keep in mind that they will erase any programs you have in your brick. Select Simple from the Download menu, and it will install these programs for you. In the appendix at the end I have included the code used for these programs.
Attach motors to A and B. Edit the Test.html file to set your IP address. Open the Test.html file in a recent version of a browser that supports JavaScript. Press the buttons, and watch to see if the motors are activated.

Troubleshooting:

WebBrick does not start correctly:

Check to make sure the regular Lego software is working correctly.
Afterwards, shut down the Lego software and start WebBrick.
Check to make sure your machine is on the network.
Check the COM port in WebBrick to make sure it is correct.
Are you running Win98, Win2000, WinNT? WinME or Win95 might have problems.

Pressing buttons on the sample webpage code does not work:

Make sure you edited the URL to be the URL of your machine.
Do you have a firewall that is blocking connection attempts?
Do you have a proxy server that is doing something strange?
Is JavaScript enabled on your browser? Are you using a browser that supports JavaScript?

WebBrick lights flash green when buttons on the web page are pressed, but the RCX does not respond correctly.

Is the IR close and in a clear line of sight to the brick?
Does the brick work well with the regular Lego software?
Has the brick been programmed correctly? Do the programs run properly when manually selected?

Making your own interface

It helps to know a little bit about JavaScript, but you can make a pretty good user interface of your own design with only a little knowledge. The correct way to do this is with the WebBrick Javascript API. This provides some standard functions you can use in your code that work across different browsers and that make interacting with WebBrick easy. You can get the WebBrickAPI.html Version 1.0 here. It includes some examples of how you can interact with WebBrick from JavaScript.

Cut and paste the API code into your web page interface. You will then be able to use simple JavaScript commands to control your brick.

Executing Programs

To execute a program, use the DoExecute function. You can call this from a button. The syntax is DoExecute(program,task). For example:

<FORM>
<INPUT TYPE=BUTTON VALUE="Run Program 1" ONCLICK="DoExecute(1,0)">
</FORM>

Getting Feedback from the Brick

To check the sensor values or to see if the motors are running etc, you use the DoPoll command. The syntax is DoPoll(source,number,on_reading), where on_reading is some JavaScript code you want to execute when the brick responds. This code can also use the special variable Reading, which will contain the result of the response from the brick. Currently, DoPoll can only read positive values. For example:

<FORM NAME="read_sensor">
<INPUT TYPE=TEXT VALUE="No reading yet" NAME="sensor_reading">
<INPUT TYPE=BUTTON VALUE="Get Sensor Reading" ONCLICK="DoPoll(9,1,'document.read_sensor.sensor_reading.value=Reading')">
</FORM>

The following table has a list of codes you can use in DoPoll

Poll source and number codes

0 Variable (0-31)
1 Timer (0-3)
2 Unused
3 Motor status (0-3)
4 Unused
5 Cybermaster tacho (0-1)
6 Cybermaster tacho speed (0-1)
7 Cybermaster motor current (2)
8 RCX Current program ID
9 Sensor Value (0-2)
10 Sensor Type (0-2)
11 Sensor Mode (0-2)
12 RCX Sensor Raw (0-2)
13 RCX Sensor Bool (0-2)
14 RCX clock (0)
15 RCX PBMessage (0)
16 Cybermaster AGC

Setting Variables

Use DoSet to set the values of variables. The syntax is DoSet(variable,value). Variables are a little tricky to use. The brick code uses the variables, and you need to determine which ones are safe for you to access from JavaScript. The code on the brick may be using the variables for its own purposes, so be careful when you set them. Here is an example that lets the user type in a value, and that value is set in variable 10.

<FORM NAME="setvar">
<INPUT TYPE=TEXT VALUE=0 name="varvalue">
<INPUT TYPE=BUTTON VALUE="Set Variable 10" ONCLICK="DoSet(10,'document.setvar.varvalue.value')">
</FORM>

Check here for code examples.

Appendix 1.

These are the C programs that are set into the 5 slots when you download them from WebBrick

// Slot 1: Run motor A backward for 5 seconds
				m_Spirit.SelectPrgm(0);
	 			m_Spirit.BeginOfTask(0);
					m_Spirit.Off("motor1motor2");
					m_Spirit.SetRwd("motor0");
					m_Spirit.On("motor0");
					m_Spirit.Wait(2,50);
					m_Spirit.Off("motor0");
				m_Spirit.EndOfTask();

// Slot 2: Run motor A forward for 5 seconds
				m_Spirit.SelectPrgm(1);
				m_Spirit.BeginOfTask(0);
					m_Spirit.Off("motor1motor2");
					m_Spirit.SetFwd("motor0");
					m_Spirit.On("motor0");
					m_Spirit.Wait(2,50);
					m_Spirit.Off("motor0");
				m_Spirit.EndOfTask();

// Slot 3: Run motor B backward for 5 seconds
				m_Spirit.SelectPrgm(2);
	 			m_Spirit.BeginOfTask(0);
					m_Spirit.Off("motor0motor2");
					m_Spirit.SetRwd("motor1");
					m_Spirit.On("motor1");
					m_Spirit.Wait(2,50);
					m_Spirit.Off("motor1");
				m_Spirit.EndOfTask();

// Slot 4: Run motor B forward for 5 seconds
				m_Spirit.SelectPrgm(3);
				m_Spirit.BeginOfTask(0);
					m_Spirit.Off("motor0motor2");
					m_Spirit.SetFwd("motor1");
					m_Spirit.On("motor1");
					m_Spirit.Wait(2,50);
					m_Spirit.Off("motor1");
				m_Spirit.EndOfTask();

// Slot 5: Beep, then run motor C forward for 50 seconds
				m_Spirit.SelectPrgm(4);
				m_Spirit.BeginOfTask(0);
					m_Spirit.PlaySystemSound(1);
					m_Spirit.Off("01");
					m_Spirit.SetFwd("2");
					m_Spirit.On("2");
					m_Spirit.Wait(2,500);
					m_Spirit.Off("2");
				m_Spirit.EndOfTask();