Introduction: Line Following SRK Robot With 3d Printed Parts

The SRK+Line Following Robot is the MRK+Line Following Robot's little brother. It uses a different type of board and a different type of motor. (The noise the motors make is what I imagine a giant beetle would sound like, therefore The BeetleBot)

With the SRK + Line kit, you can build your own line following robot. The platforms are sturdy and metal, but rectangular. We wanted to create open source robots parts that have a smoother design, but are still strong enough to drive around.

Step 1: The Parts List

  1. Hardware: everything you need you can get from the Line Following Servo Robot Kit.
  2. 3D Printed Parts:
    1. BasePlate (Credit)
    2. Servo Motor Mount (Credit)
    3. Sensor Bracket (Credit)
    4. Drag button
  3. Tools:
    1. Small Screwdriver
    2. Computer with MPIDE
  4. 4 AA batteries
  5. Misc: the Line Following Servo Robot Kit has all the required nuts and bolts for the original parts, but because we're changing stuff around, I used these 6-32 thread nuts and screws.

Step 2: Attaching the Sensor Bracket and Drag Button

  1. Use the first and last holes in the first row to attach the slim sensor bracket to the baseplate.
  2. Attach the drag button to the back of baseplate. There will be a section designed to make sure the drag button is secure.

Step 3: Attaching the ChipKIT Connectors

It's easiest to attach all the connectors before we attach the boards and everything. We want to attach the chipKIT connectors first, the board is 6x5, so we can't make it perfectly symmetrical with the baseplate. It's easiest to base where the screws should go using the drag button screw.

  1. With the baseplate top facing down, and the drag button near you, attach the first connector 3 holes up from, with the starting point being "0".
  2. Attach the next connector 5 up from the connector from step 1. This should be in the raised grid section.
  3. The next 2 connectors will both be 4 holes to the right of the 2 connectors.

Check out the pictures with the green arrows to double check everything, the third picture is where the connectors will be when you flip the connector right-side up.

Step 4: Attaching Pmod Clips

There are two Pmod clips on the top-side that we are going to attach

  1. The first one will hold the PmodCON3, which connects directly into the chipKIT. Check out the pictures the first two pictures above to see where it should be connected.
  2. The second will hold the button module, pictures 3 and 4 show where that should be connected.

Step 5: Attaching the Servo Brackets

Next we want to attach the servo mount brackets. There are 4 screw holes on each of the servo brackets, you probably don't need all 4 for everything to be secure.

On the bottom-side of the baseplate, both sides have sections deisgned for servo bracket mounting. Attach the two brackets on those spots.

Step 6: Attaching the Servo Motors

Next we want to attach both the Servo motors to the Servo mounts. Pop the Servo into the square with the white wheel facing outwards and oriented to the sensor bracket.

Screw these in. Because the mount has to be attached first, the screws may be a little difficult to get everything secure.

Step 7: Putting the Sticky Tires on the Wheels

In the next step we're going to attach the wheels, so we want to get the tires all set-up. This might be a little tough, if you have extra hands around, you might want there help.

Step 8: Attaching the Tires to the Servos

Now it's time to attach the Sticky Tires to the servos.

  1. First we want to unscrew the white wheels from the servo. There's is a black screw keeping them in place. I recommend grasping the white wheels before trying to unscrew them.
  2. Attach the wheels to the Servo, they will only go on one way.
  3. Screw the black screw back into the servo.

Step 9: Attach the Bottom-side Pmod Clip

The last Pmod clip is for the PmodLS1

Attach it using the pictures above as a reference. (2 up, 1 over from the right-hand drag button screw)

Step 10: Attach the ChipKIT MX3 to the Board

Now it's time to start attaching and connecting all the hardware!

Attach your chipKIT MX3 onto the board using the 4 connectors we added earlier. Be sure to have the power plug in facing frontwards!

Step 11: Connecting the PmodCON3

With the chipKIT on the board, connecting the PmodCON3 will be a snap (ahahahaha).

Attach the CON3 to the Pmod clip by the JC ports, then connect the Pmod with the board by using the bottom connectors (pins 6-12). It should only really fit into the bottom row.

Step 12: Attaching the Button Module

Now we want to attach the Button Module to the chipKIT.

First, attach the Button Module to the other top-side Pmod Clip, orient it facing away from the direction of the drag button.

Next, attach the 6-pin gender changer to the 6-pin connector and attach it to the top part (pins 0-5), with the flower not visible.

Attach the female end of the 6-pin connector to the Button Module. Loops are completely optional, but I enjoy how it looks.

Step 13: Attaching the Cables to the ChipKIT

Take the cables from the Servo Motors and bring them to the PmodCON3. You can do it the way the pictures show, or any other way.

Attach the left cable to P4, make sure the Black end goes to GND and the White end goes to SIG.

Attach the right cable to P3, make sure the Black end goes to GND and the White end goes to SIG.

Step 14: Attaching the Battery Case and Batteries

Flip everything over (don't worry, all the connections will be fine).

Now we're going to attach the battery case.

I recommend taking the velcro off and attaching one side to the battery case and one side to the baseplate, then attaching the battery case. Previous robots had battery case sticking problems if both side weren't secured.

Orient the battery case so that the wire is as shown in the pictures above.

Then add the batteries to the case.

Step 15: Connecting PmodLS1 to the ChipKIT

Now we want to connect the PmodLS1 to the board.

First plug the 6-pin connector to the Pmod with the flower side showing.

Loop the connector over the edge and connect it using a 6-pin gender change. Attach it to the bottom sections of the JB port (pins 6-12) with the flower side not showing.

Step 16: Attaching Your IR Sensors

Cut the Velcro in half and attach it to the Sensor Bracket, with about one screw hole distance between the two strips.

Attach the 4 IR Sensors to the Velcro, pull the cables through the slot in the Sensor Bracket.

Step 17: Attaching Your IR Sensors (cont.)

Now it's time to plug in the IR Sensors to the PmodLS1.

The pictures might look a little crazy, but we're gonna go over them.

The PmodLS1 has a grid system of colors and numbers. All the wires on the cables connect on a one-to-one color ratio, so just make sure that ORG goes to ORG, etc.

To connect the cables, we want to go left to right, and plug it into the Pmod starting with S1 and just incrementing each time. If you loop each cable around the 6-pin connector each time you attach it, you'll get the second picture.

Step 18: Sending Power to PmodCON3

Now we're going to send power the PmodCON3, there will be some red and black wire with a connector on one end. On the PmodCON3, there is a power hub, with + and - ports. Put the red wire into the + side of the hub and tighten the screw. Now place the blac wire into the - side and tighten the screw.

With the connecting end, attach it to the J6 Pins with red on the + pin and black on the -.

Step 19: Programming Your Robot

Click here to download the demo project, open it using MPIDE.

To upload the code you must do several steps.

  1. Plug the cable into the chipKIT MX3 and then into the computer.
  2. Change the board to be the chipKIT MX3 in MPIDE
    1. Click on Tools->Board->chipKIT->chipKIT MX3
  3. Click on the Upload button

After the program has uploaded successfully, unplug the robot from the computer.

Step 20: Finishing Up!

Now everything should be all set to line-follow!

Plug the connector from the battery into the J5 plug by the CON3 power cable. Be sure to have Red on +!

At this point everything should be (almost) all set to run! After the green LED stops blinking, press BTN2 on the Button Module to start and stop the robot!

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