ezsystem elab16m Light Sensing Robot

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Lorraine Tyler
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1 ezsystem elab16m Light Sensing Robot ezsystem The aim of ezsystem is to enable Creativity and Innovation at an early age in a Problem Based Learning (PBL) approach. ezsystem integrates ezcircuit Designer, ezcorechart and the elabtronics PIC microcontroller boards into a user friendly training system. ezcircuit Designer speeds up the design of the hardware. ezcorechart uses menu based FORMS to speed up the programming of the microcontrollers. Learning Outcome This workbook provides the user with hands on experience on how to use ezsystem to design, build, test and program a Light Sensing Robot as well as give a brief introduction to PIC microcontrollers and electronics. Equipment for workbook Computer PC running Windows 2000 SP4 or higher with USB connections Software Microsoft.NET Framework V2 or higher ( Required to run ezcircuit Designer ) ezcircuit Designer Version or higher CoreChart Version or higher Hardware elab16m Controller Board elabtronics USBP Programmer with USB Cable elabtronics robot base and 4x AA batteries 2x Light Dependent Resistor (LDR) Piezo buzzer Small flat head screwdriver 1 ezsystem elab16m Light Sensing Robot

Step 1: Design the Light Sensing Robot The robot will use Light Dependent Resistor (LDR) sensors to control its motors.

The robot project will then be extended to incorporate an additional LDR so the robot will move toward sources of light. a. Start ezcircuit Designer.

In the chip selection window click on elab16m in the model column and click OK. Click OK on the confirmation window. e. Select Buzzer in the Circuit Groups menu and click pin A0.

Select LDR in the Circuit Groups menu and click pin A3. g. Rename the LDR to LightSensor_L h.

2 Step 1: Design the Light Sensing Robot The robot will use Light Dependent Resistor (LDR) sensors to control its motors. This will allow the robot to follow a line dividing a light and dark surface. The robot project will then be extended to incorporate an additional LDR so the robot will move toward sources of light. a. Start ezcircuit Designer. On the menu click File and select New to start a new project. b. In the name field type Light Sensing Robot and click OK. c. On the menu click Options and select Chip Selection d. In the chip selection window click on elab16m in the model column and click OK. Click OK on the confirmation window. e. Select Buzzer in the Circuit Groups menu and click pin A0. Figure 1.1 a. Right click on Buzzer20 and select Rename b. Type Buzzer and press enter on the keyboard. Figure 1.2 f. Select LDR in the Circuit Groups menu and click pin A3. g. Rename the LDR to LightSensor_L h. Select LDR again in the Circuit Groups menu and click pin A1. i. Rename the second LDR to LightSensor_R 2 ezsystem elab16m Light Sensing Robot

3 j. Select Motor Driver in the Circuit Groups menu and click on the pins B4, A7, A6 and B5 in this order. k. Rename Motor1Forward8 to Motor1_Forward, Motor1Reverse9 to Motor1_Reverse, Motor2Forward2 to Motor2_Forward and Motor2Reverse3 to Motor2_Reverse. Figure 1.3 Step 2: Build the Light Sensing Robot Build the project by following the design created in ezcircuit Designer. The power supply, buzzer, two LDRs and two motors are required to build the light sensing robot. Connect them as follows: a. Place the four AA batteries into the battery holder under the robot base. b. Connect the large white 3 pin power plug on the robot base to the white socket near the ON/OFF switch on the controller board. c. Connect the 2 pin motor connectors as shown in figure 2.1. Take note of the red and black wires orientation. KEY Figure 2.1 Motor1 = Black A6 + Red B5 Motor2 = Black B4 + Red A7 3 ezsystem elab16m Light Sensing Robot

d. Connect the white wire of the buzzer to terminal A0 and the black wire to the negative ( - ) terminal. e.

rst LDR to terminal A3, the black wire to the negative terminal and the red wire to the positive ( + ) terminal. f.

2 Step 3: Test the Outputs The light sensing robot has been designed and constructed.

4 d. Connect the white wire of the buzzer to terminal A0 and the black wire to the negative ( - ) terminal. e. Connect the white wire of the first LDR to terminal A3, the black wire to the negative terminal and the red wire to the positive ( + ) terminal. f. Connect the white wire of the second LDR to terminal A1, the black wire to the negative terminal and the red wire to the positive terminal. Figure 2.2 Step 3: Test the Outputs The light sensing robot has been designed and constructed. Testing will check that the output circuits and the controller board are connected and working correctly. a. Check that ezcircuit Designer is running and the Light Sensing Robot project is open. b. To send the design to ezcorechart, select the Options drop down menu and click on Send to CoreChart. Alternatively click the Send to CoreChart icon in the icon bar. 4 ezsystem elab16m Light Sensing Robot

When a design is sent from ezcircuit Designer to ezcorechart, a test subroutine is automatically generated for each of the output circuits in the design. Figure 3.1 c.

5 When a design is sent from ezcircuit Designer to ezcorechart, a test subroutine is automatically generated for each of the output circuits in the design. Figure 3.1 c. Save the ezcorechart program by selecting File on the menu and click Save As. In the name field type Light Sensing Robot and click Save. d. Connect the USB cable of the elabtronics USBP Programmer to the USB port on the computer. e. Connect one end of the 10 pin programming cable to the USBP Programmer and the other end to the elab16m controller board. f. Check that the battery pack is connected and the power switch is ON. g. Click the Send Program To Chip button. When prompted to save the program click OK. h. Wait for the program to download to the chip. If the download is successful the status bar will turn green and Write Successful will be displayed. The USB programming window will close automatically. i. On the elab16m controller board switch the power OFF. j. Disconnect the controller board from the USBP Programmer. After a few seconds switch the power ON k. To run the test program push and release the push button switch on the elab16m controller board. The test program will separately turn each of the outputs on for two seconds and then turn them off. 5 ezsystem elab16m Light Sensing Robot

Step 4: Program the Light Sensing Robot The light sensing robot is initially programmed to use a

shift on the keyboard, select the last test subroutine (icon 3). b.

6 Step 4: Program the Light Sensing Robot The light sensing robot is initially programmed to use a LDR to follow a line that separates a light and dark surface. a. Delete the test subroutines by selecting the first test subroutine (icon 2) and while holding shift on the keyboard, select the last test subroutine (icon 3). b. Click delete in the icons bar or push the delete key on the keyboard c. When prompted to confirm the delete click OK d. Select Inputs in the ICONs menu. In ICON Properties click AnalogConv. e. Click the black arrow below START MAIN to place the AnalogConv. Figure 4.1 f. Double click AnalogConv to open its options form. g. In the SOURCE field select LightSensor_L and in the DESTINATION field type Light_Left. Figure ezsystem elab16m Light Sensing Robot

h. In the ICONs menu select Numbers and in ICON Properties click Compare. i. Place the compare below icon 2 and double click on it to open the options form. j.

7 h. In the ICONs menu select Numbers and in ICON Properties click Compare. i. Place the compare below icon 2 and double click on it to open the options form. j. In the SOURCE field select Light_Left and in the COMPARE WITH field type 3v. Select the Above and Below check boxes and click OK. Figure 4.3 k. Place an OnOffPin below the IF Below (icon 4). In the icons options form select Motor1_Forward and ON. l. Place another OnOffPin below the first (icon 5). In the icons options select Motor2_Forward and OFF. m. Click on icon 5 and while holding shift key on the keyboard click icon 6. In the ICONs menu select Group and in the Group_Name filed type Turn_Right and click the Create New Group button. n. Double click on either the first or last icon of the subroutine to return to the main program. o. Place an OnOffPin below the IF Above (icon 6) to set Motor2_Forward ON. p. Place another OnOffPin below icon 7 to set Motor1_Forward OFF. q. Create another group from icons 7 and 8 called Turn_Left. Return to the main program. r. Finally place a GoTo at the end of the program (below icon 7). 7 ezsystem elab16m Light Sensing Robot

Convert to digital and store the LDR s value Compare the digital value to a set point If Below set point Turn Right If Above set point Turn Left Figure 4.4 s.

Place the robot on the edge of a light and dark surface and position the LDR connected to A3 pointing directly down at the line and the robot will follow the line.

8 Convert to digital and store the LDR s value Compare the digital value to a set point If Below set point Turn Right If Above set point Turn Left Figure 4.4 s. Save the program and send it to the chip t. Press the push button switch to run the program. Place the robot on the edge of a light and dark surface and position the LDR connected to A3 pointing directly down at the line and the robot will follow the line. Note: Depending on the level of light in the room, the value of the set point may need to be adjusted. Subtract or add 0.1 to the value until an optimum value is found for the robot to follow the line. 8 ezsystem elab16m Light Sensing Robot

9 The light seeking robot program can be extended by adding another LDR to enable the robot to change direction towards the area of higher light level. The robot will now effectively be a light seeking robot as it will move towards the greatest level of light. u. Place an AnalogConv below the other AnalogConv (icon 2) and in its options form select a SOURCE of LightSensor_R and type Light_Right in the DESTINATION field. v. Double click on the Compare (icon 4) and change the COMPARE WITH field to Light_Right. w. Save the program and send it to the chip. x. Position the LDRs as shown in Figure 4.5 A3 LDR A1 LDR Robot Base Figure 4.5 y. Use a small piece of heat shrink to slide over each of the LDRs. Use a light source to calibrate how close the LDR needs to be to the opening of the heat shrink. While holding the running robot directly in front of a light source the robot will make either the left or right wheel spin when the robot is moved slightly to the left or right. Adjust the heat shrink so that very small movement left or right of the light source will cause the robot to change direction. Figure 4.6 The robot will now seek out light and move in the direction of the greatest level of light. 9 ezsystem elab16m Light Sensing Robot

10 Step 5: Extend the Program Work through the following extensions and devise a solution to the problem as there are still some areas where the light sensing robot can be improved. Make small changes to the program and run the program regularly as you progress. Extensions: Make the robot seek darkness instead of light? 1. Modify the light sensing robot program so that the robot will move in the direction of the lowest level of light instead of the highest. Hint: The options in the Compare icon used in the program could be changed to make the robot move away from the highest level of light. The buzzer added in the design section can now be implemented to buzz when the robot finds a high level of light. 2. Modify the light sensing robot program so that the buzzer will sound when either of the robot LDRs is exposed to a high level of light. Hint: Additional Compare icons can be used to decide if the buzzer will sound. Use a large value like 4 for the COMPARE WITH value. ezsystem elab16m Light Sensing Robot is now completed. 10 ezsystem elab16m Light Sensing Robot

A servo is an electric motor that takes in a pulse width modulated signal that controls direction and speed. A servo has three leads:

Project 4: Arduino Servos Part 1 Description: A servo is an electric motor that takes in a pulse width modulated signal that controls direction and speed. A servo has three leads: a. Red: Current b. Black: