J-BOT OFFICE ROBOT | JAMECO PART NO. 2157124

Experience Level: Intermediate/Beginner (requires soldering)

Time Required: 2-3 hours depending on experience

Kit Includes:

Part No. Qty. Description

282861 1 PING))) Ultrasonic Distance Sensor

358635 1 Standard R/C Servo

139222 2 Spacer, 1/4 Hex, Aluminum

20601 1 Breadboard, 3.3" x 2.1"

222010 1 USB 2.0 Cable, A/B, 6'

2109931 1 Cable, 3-wire extension, 3-pin female conenctors

2146011 1 4-40 Hardware kit

2146345 1 4WD Platform w/ Included Romeo Controller

2112444 8 Battery, Alkaline, AA

--- 1 Instructions

I wanted to make the Jbot easier for hobbyists to build, so I redesigned the Jbot. The Jbot now comes with the Romeo board. The board comes with an Arduino microcontroller and an H-bridge to control the motors.

Step 1 - Building the 4 wheel drive platform

First solder about 5 inches of wire to each motor. After soldering, put a drop of hot glue to the copper clips on the motor, so the clips do not rip off because they are very fragile.

Then solder the switch and the battery pack together as shown below, but do not connect it to the board yet.

Next add the motors to the side plates as so, take note of the direction of the motors.

Next use the two flat head screws and nuts to attach the battery pack to the lower plate, the lower plate does not have as many holes on it as the other plates.

Put the switch on the bezel piece where the two holes are.

Attach the bottom plate to the sides where the motors are, also attach the wheels to the motors at this time in order to avoid getting the shafts damaged. The wheels just slide onto the shafts. You can add a drop of hot glue to each shaft to prevent the wheels from sliding out.

Next attach the two bezels to the sides of the platform.

At this point it would be a good idea to label all the cables so you can identify them later. I decided to label them by using regular scotch tape. I labeled the two front motors "FL" and "FR" for front-left and front-right, as well as the back as "BR" and "BL" for back-right and back-left.

When you are placing the bottom plate on the platform make sure the wires come out from where the motor terminals are on the board

Test to make sure the motors are in series:

Take both sets of wires from the left side (front left and back left) and test them with an AA battery (not included) to make sure they are wired correctly. Both of the wheels should go the same direction. We are wiring the motors in series. If they are not going the same way, you should flip the wiring for only one of the motors. Check the right side as well.

After making sure that the motors are wired correctly, put the left side to the terminal labeled M1. Put the right side to terminal M2 as shown below. Also connect the battery pack to the board.

At this point I would like to make sure everything is connected correctly. On the Romeo board, make sure the jumper from next to the power terminal is not on.

The pins labled: 6,7,4,5 should have the headers on, these are the ones that connect the H-bridge to the controller.

Time to test the connections:

First you will need to download the Arduino software: http://www.arduino.cc/en/Main/Software

One it is installed, paste the following code (Motor test_1) into the box. You can find the source code here: http://www.jameco.com/Jameco/Products/ProdSW/2157124AdditionalFiles.zip. Once you paste the code, click on the check mark to verify that the code compiled. Next go to “Tools”, “Board”, and select: “Arduino Duemilanove w/ATmega328” Once you select the board, connect it to the Romeo Controller, and click on the arrow pointing to the right to upload the code to the board. You should see flashing lights on the board; that means it is being programmed.

Once you program the board, flip the switch to provide power to the motors. Still connected to your computer, select the magnifying glass on the Arduino compiler to go to the serial monitor. On the serial monitor, change the baud to 19200.

To make sure It was wired correctly, type one of the following letters into the serial monitor and the wheels should turn.

Letter Action

w Both sides should move forward.

s Both sides should move backwards.

a The platform should move left.

d The platform should move Right.

x All STOP

When you press w (forward), the platform should move forward. If one side turns back and the other side turns forward, switch one the positive and negative wires on only one side on the board.

Next we will build the upper plate of the Jbot. We included the breadboard for future development of the Jbot. Step 4 - Adding the PING sensor

We will use the aluminum piece that came with the breadboard to make a holder for the Ping sensor. Put the sensor on the aluminum piece and mark it with a Sharpie. I used regular scissors to cut the aluminum piece.

Use the edge of a desk or table to fold the aluminum into a 90 degree angle. I used a small piece of Velcro to stick the sensor to the mount.

I decided to stick the sensor to the mount with Velcro. The servo was attached to the servo hole on the top of the shield by using the standoffs, two screws and two nuts.

Hook up the Ping sensor to pin 9 on the board and the servo to pin 10.

Lastly, attach the top plate to the platform.

The last step is to program the Jbot. Copy and paste THIS code into the Arduino compiler and upload it to the board. After importing the Arduino code, make sure to replace the header next to the power source so it can also power the Arduino chip.

And there you have it! Stay tuned for future updates on the Jbot. If you would like to change the older version of the Jbot with this new controller, you can purchase the Romeo microcontroller PN: 2144403

Note: Pictures taken from DFrobot.