Intro: Lego Chassis for Raspberry Pi Robot
I'm fairly new to Raspberry Pi and one of the projects I wanted to try was to build a robot. So I bought the "CamJam Edukit 3: Robotics". I think it's a good robot kit to start with, because it provides easy to follow worksheets to help with the build. But one thing is lacking in the kit and it's a chassis.
The makers of the kit suggest using the cardboard box the kit was shipped in or 3D printing a chassis.
It didn't have a 3D printer and I didn't like to use cardboard, so i decided to try something different.
I got out all of my old LEGO boxes, to try and build a chassis out of LEGO. I ended up using a box of LEGO Technics because it seemed to be sturdy for building a robot.
In this instructable I will show you all the steps for recreating my Chassis. It took me quite some time to figure out how to attach all the robot parts on my chassis.
You can build your own design of course, but this tutorial can provide you with some ideas.
Step 1: Build Two Sides
To make this instructable clear, I made 2 photos for each step. One photo with the parts you need, and one showing the parts added the overal chassis.
For this first step you need to make the two side of the chassis. I had special blocks, on which I could add some rubber pieces, so they sort of look like a bumper. If you don't have those, you can just use normal blocks. I just liked how the bumpers looked for my robot. I think the hardest blocks to find might be the angled blocks I used in this step.
Use 2 angled blocks and two straight ones and connect them together with 2 flat blocks. Do this again for the other side.
Step 2: Attach the Two Sides Together
Put two little black pins inside the red block.
Attach the red block to the 2 sides you made in the previous step.
You should now have the basic shape of the chassis.
Step 3: Attach the Flat Red Block
Attach a flat block to the underside of the chassis. This will make it all a bit stronger.
Step 4: Put Small Pins in the Chassis
In the next step we're going to add extra blocks to the sides of the chassis. Put the pins in place so that you can add the blocks later.
Step 5: Add Blocks to the Sides
Add the blocks to the sides of the chassis.
Step 6: Attach Motors to the Chassis
Adding the non-LEGO parts to the chassis proved to be quite a puzzle.
I used two blocks the same size of my bumpers. (here I didn't use the bumper ones, because the wheels have to be attached to the outside)
Use a flat long block to attach them. The long block sticks out a bit, so it can be attached to the rest of the chassis. To make it sturdy I also added a second layer to the inside of the chassis, I used 1 long block for that, and again I attached it using little pins.
Use one red block to put the motor against. I ended up using some of the double sided tape that came with my robot kit. To make sure it wouldn't move, I put zip ties through the holes of the block and motor. Of course you make two of these, since there's two motors.
I used a long red block to attach to both sides of the chassis. The little red corner flat blocks, are used to keep the long red one in place.
I made use of the holes in the Technic blocks to put my wires through, this keeps everything nicely out of the way once the robot is riding around.
Step 7: Make the Front of the Chassis
I made the chassis 3 layers thick on the front. This is handy when attaching the breadboard.
Put the little pins inside the black blocks. Attach the blocks to each other. I used 3 "bumper" blocks for the outside layer, but you can use normal blocks.
Attach the 3 layers to your chassis.
Step 8: Attach the Back Wheel
The robot has two motors, and uses a small "ball" for back wheel. First I used this wheel, but now I'm using a bigger wheel that didn't come with the kit. (The wheel from the kit, didn't turn very well and came off the chassis quite quickly)
For attaching the big wheel I used two long flat red blocks. I used some of the double sided tape to attach the wheel to those blocks. Then I used zip ties to make it stronger.
Attach the long flat red blocks with the wheel, to the middle of the chassis.
If you are using the small "ball" as a wheel: I drilled tiny holes in block that is used for wheels of small LEGO cars from a basic LEGO kit. I used the provided screws to attach the wheel to the block. Then the block can easily be attached to other parts and to the chassis.
Step 9: Finish Off the Chassis
Up till now the chassis was not that strong. This is why we are adding a top layer to the chassis. This will make it a lot stronger, but also looks nicer.
Attach two long black flat blocks to both sides. Use the smaller red ones at the front and back.
Step 10: Attach the Front Wheels to the Motors
The robot kit came with two red wheels, this is why I've been using black and red blocks. ;-)
Put the wheels on the motors.
Step 11: Attach the Bumpers (optional)
I used special blocks that can be used to attach a rubber to.
Simply push them onto the blocks.
Step 12: Strengthen the Back Wheel
Use a long flat red block and a small flat red block to put on top of the long blocks from the back wheel.
This keeps the wheel in place better.
Step 13: Blocks for Attaching the Raspberry Pi
My raspberry pi is in a pibow case with a LEGO layer on the bottom. This way it can easily be attached to my chassis. The two longer red blocks are for attaching the raspberry pi. The short ones are used to keep a battery pack in place.
Step 14: Attach the Line Following Sensor (optional)
The kit came with a line following sensor.
Attach the line following sensor to a flat block with holes in it. For this i used a zip tie.
I then used a few extra blocks to get the sensor closer to the ground.
Attach this to the front, underside of the chassis.
Step 15: Attach the Battery Box to the Chassis
The kit came with a battery box, to power the motors.
This was easy to attach. It fits snuggly inside the middle of the chassis. I put the wires through the long red block in the middle again.
Step 16: Finish Off Your Robot
Your LEGO chassis is now finished.
Attach the raspberry pi to the chassis on the red blocks.
Also attach the breadboard.
Once you've build the entire robot, you can easily put a cell Phone battery charger between the red blocks to give the raspberry pi power.
Enjoy your LEGO raspberry pi robot chassis!
I'm entering this instructable in a few contests, so if you like it, please vote.
Also, i'm not a native English speaker, so I'm sorry if there are some mistakes.