Stair Climber

Using the 3d printer and laser cutter along with the basic bot components I have created the first prototype for a robotic stair climber

Supplies

The supplies needed include

• Software
• fusion 360
• Adobe Illustrator
• Ultimaker Cura
• Creality Print
• Tools
• Laser cutter
• 3D printer
• Materials
• MDF (wood)
• PLA (Plastic)
• Super glue
• wood glue
• Basic bot kit
• 6 AA battery holder
• 6 AA battery's
• 9 Volt Heavy duty battery snap
• HM-10/AT09 Bluetooth Module
• Motor x4 (only 2 included in the kit 2 additions necessary)
• Jumper Wires (male to female & female to female)
• 3x12 mm screws
• 3x8 mm screws
• 3x6 mm screws
• 2.5 hex Allen key wrench
• 4-Tip Combination Philips/Slot Screw driver
• 22AWG wire bundle
• switch
• Arduino Mega
• DK Electronics Motor controller

Step 1: Measure the Stair

Get All of the dimensions of the stair that the robot will be climbing

Include:

• height
• depth
• width
• depth of overhang (if applicable)

Step 2: Design the Chassie

1. Using adobe illustrator design a chassie that will allow for the robot to surround the stair (it should begin in an L shape)
2. fillet the corners that will be closer to the stairs
3. when in motion these corners will come in contact with the stairs and put the robot off balance
4. Fillet the back corner of the machine
5. this will allow the robots center of gravity to remain overtop of the stair being climbed and ensure that the robot does not fall backwards
6. add finger's to the chassie that will allow for the attachment of the 3rd dimension, make the chassie ~8cm
7. cut holes for the motors and the power switch
8. test the chassies construction using fusion 360 (MAKE SURE THAT THE SCALING IS UNIFORM)
9. make adjustments to the design based on the fusion 360 mockup
10. return the design to adobe illustrator

Step 3: Cut and Assemble the Chassie

1. Using the laser cutter cut out the designed chassie in step 2 onto 3mm MDF wood
2. assemble all of the pieces using superglue (one may want to use tape first to avoid error)
3. leave off the top wall and one side of the chassie to allow for internal components

Prototype During this step

1. The issue for prototype 1 was a failed scale
2. next I will re cut it with the proper scaling
3. The issue for prototype 2 was incorrectly set margins for the laser cutter
4. next I will re cut it with the proper margins
5. The issue for prototype 3 was an incorrect edge correction
6. next I will redesign the entire piece so that the component will get cut to the correct size the first time
7. the issue for prototype 4 was an incorrect size of the piece this issue made a gap in the chassie
8. next I will redesign the piece so it fills in the gap properly
9. the issue for prototype 5 was an incorrect size of the component (similar to the last prototype but with a different piece
10. next I will redesign the component and re cut it

For all of the prototypes I suspect that the sizes were thrown off because of the scale transfer between the original

illustrator file and the fusion file that I used to check the sizes. If I did this project again I would make sure that it is

scaled correctly when transferring

Step 4: Design and Cut the Wheels

design the shape of the wheels

the shape should consist of hooks that will allow the robot to climb the stairs I went for a rounder design to allow for easier driving of the robot

make sure that you cut a hole in the middle of the robot that is the same shape as the motor axles that you will be using

the wheel should be taller than the stair to allow the bot to climb

My design for the wheels are included in the following file

Step 5: Set Up Wires

1. attach the arduino mega to the motor controller
2. attach the motors to the motor controller
3. attach the battery to the switch
4. attach the switch and battery combination to the motor controller

Step 6: Print Brackets and Holders for the Motors

1. print brackets for motors using the Rapid Prototyping files (print 2 right and 2 left)
2. print top holder for the front motors
3. print bottom holder for the back motors (could alternatively use a laser cut piece

Prototypes for this step

1. This step only had 1 prototype and it was to see if I could alter the point that the motor attaches to the frame of the chassie
2. this was a failure because the replacement of the fastener was to damaging to the component to it didn't attach properly to the frame anymore
3. Next I am going to try put the fastener in the right spot from the original print

While making this prototype I experimented with sauntering using PLA and 3d print designs

Step 7: Assembly

Put together all the components

1. fasten the Arduino mega/motor shield to the front angled portion
2. this ensures the center of gravity is further forward because the weight is forward
3. fasten on the top and bottom holders on the top and bottom portions of the robot respectively
4. Fasten the motor brackets to the top and bottom holders (put the left on the left and right on the right)
5. insert the motors into the brackets
6. fasten the final side of the chassie with superglue
7. fasten the wheels (read more on the final page)

Step 8: Code

Download the following code to your Arduino mega, make sure you use the appropriate libraries (Dabble and ADAfruit)

The top 5 are the components to a work in progress code that will allow the bot to utilize the Bluetooth connector in order to

• turn
• drive forwards
• drive backwards
• stop

The bottom file includes code that will make to bot drive forwards when there is power supplied to the Arduino by using the power switch (It will not connect to the dabble app using the Bluetooth connector)

Step 9: Next Time

If I had more time to complete this project and all of the machines (laser cutter and printers) were available I would have changed my project in the following ways

1. Created a turning feature
2. coding the enhanced motor controller was a very large challenge whilst doing this project. Because of this I was unable to complete the code to make the robot turn as well as connect to the dabble app
3. given more time I would spend more time learning the DK electronics motor controller as well as the various coding library's used so I would be able to create a Bluetooth connectable project
4. Stabilized the wheels
5. since the wheels were preemptively superglued to the motors they were unable to bear the total weight
6. If I was able to remove the wheels I would have created a bracket that would have better fastened the motor a prototype for this bracket is included in the images