Engineering Design Process: Beetlebot

IMAGINE

What is the goal and problem being solved? Learn about the design engineering process

Get skills: soldering, glue gun, heat shrink, instructables, wiring, motors/switches Build community by having people work with those they do not know Have to be able to complete the project in 3 hours & work in teams

Who would use it and how would it help?

Youth teachers can use the skills they gain for project building Youth teachers can use what they build to interest children in STEM this summer

Explore

What have others done? Researched many engineering design competition ideas on internet

Researched many Instructables

Design

Which of the ideas is most promising? We chose the Beetlebot v. 2 on instructables.

Test out the design

Built a prototype out of motors, materials we found around SETC Research best & cheapest materials & ordered them

Built an example project Built a demonstration course to test the Beetlebots on

Design and photos by Jerome Demers Sherbrooke, Quebec, Canada

Jerome’s instructions were modified by L2TT2L college mentors and staff based on building prototypes!

 

Beetlebot Materials

2 x 1.5V motors 2 x SPDT ( single pole double throw ) switches with a metal lever

2 x AAA battery 2 x Terminal connector

1 x AAA battery holder 1 x Plastic or wooden pearl (Spherical bead )

1 x 1 inch x 3 inch piece of metal or aluminum 1 Toggle switch for the on/off switchs

Paper clips big and small

2 feet of wires around 22/24 Gauge size Heat shrink that will fit over the motor shaft and over the terminal connector

Electric tape and masking tape

I t e m s f o r t h e b o d y s h e l l : Round plastic lid to make the shell of the robot

Spray can paint, the colour you want. 2 x Small magnets to attach shell to body.

t h e r e c o m m e n d e d t o o l s f o r t h i s p r o j e c t :

1 x safety glasses!! 1 x soldering iron

1 x glue gun 1 x wire strippers

1 x scissors, knife, x-acto, etc

How thE SPDT SWITCHES WORK

A B

COM

1 . Mounting SPDT Switches on the Battery Holder Use hot glue gun to mount the two SPDT switches. The angle matters and will determine the

responsiveness of your beetlebot! Antennas will be attached to the Swtich Levers

2. Motor SHAFT Grip

The “legs” of the beetlebot are the spinning shafts of the motors. Putting heat shrink on the motor shafts allows The bot to move around easier. Think of the heat shrink as the “tire” on a car. The car doesn’t

work well if you are driving on the rims --- you need tires to grip the road.

Use a heat gun to shrink the heat shrink onto the ends of the motor shaft. These need to be very neat in order for the Beetlebot to move easily.

3. Make the motor Mount

Cut a piece of metal approximately 1” x 3”  : Meta l is Pretty easy to cut using Metal Scissors

 

4. Attaching the Motors to Mount

Using electrical tape is a good way to attach motors to the mount. You need to be careful with the motor polarization for your bot to move correctly! This should be made easier by the fact that The Batteries we are using have

two different colored wired attached to their leads. You also need to be very careful that your motors are balanced correctly or the Beetlebot will move in circles!

5. Attaching Metal Plate to Battery Holder

Glue the metal plate to the FRONT of the Battery Holder. Placement of the Metal Plate is important so that the Beetlebot will not Tilt forward! Note that The angle of the Motor controls the Speed of the Bot!

Tip: If you simply glue the metal plate to the holder, you will not be able to adjust it, so one solution is to put masking tape on both the metal plate and the battery holder, then glue the two pieces of masking

tape together – IF you need to adjust the motor placement to make the beetlebot move smoothly Later, then all you need to do is remove the masking tape!

 

6. Making & Attaching Back Caster

Attaching a caster does 2 things: It makes the Bot able to move faster and It is used to prevent the Bot from tilting forward so the Bot can move more freely.

Bend a large paper clip with needlenose plyers & slip on a wooden bead for making the caster roll. Making the leg of the caster longer helps prevent the tilt!

Eventually you will Glue the caster to the Battery Holder. You may want to wait until the end to attach so you can position the caster so that the beetlebot will tip backwards. Use a Lot of glue to make it secure

   

 

7. Soldering Switch LEGS together

The top two switch LEGS need to be soldered together. The topmost switch LEGs can be directly soldered.

The Second switch Legs must be connected by a wire before being soldered. (NOTE: photo shows a paperclip being used to make the connection, but it is better to use insulated wire)

It may help to tin the ends of the wire slightly before soldering the ends to the Second switch Legs!

Solder legs together

Connect these legs together by soldering a wire to each

end

Black tape is covering the metal plate, so that it photographs more easily. You don’t have to do that!

A B

COM

8. Connect Com pin of Each Switch to Motor Terminal

Solder a wire that connects the Com pin of each switch to the corresponding motor terminal.

To make a secure connection to the motor & Com Pin See the technique below for bending the wire before soldering. It may help to Bend and Tin the wires Slightly before soldering!

(Note: A paperclip is used in the illustration, but it is better to use insulated wire)

   

9.

Solder a wire between the Motors Connect the bottom of the two motors with a wire. You might want to use heat Shrink (NOT SHOWN) to

strengthen the connection. It may help to tin the ends of the wires slightly before soldering!                                

         

The “Third Connection” Explained

In the AAA battery holder you have 2 wires that provide 3 Volts. In reality, the Beetlebot only uses 1.5 Volts for both motors.

How to get half the voltage?

Simple! Solder a wire like the picture in the next step!

10. Solder “The Third Connection” to the Battery Holder

Solder a wire TO THE Bottom of the Battery Holder. THIS IS VERY VERY VERY TRICKY. Be very careful when soldering to the battery holder, you can melt the battery holder!  

We found that it is safest to stick a bit of the wire through the battery holder and solder the INSIDE connection of the Battery holder rather than the outside!

The new wire connects to the wire you soldered in step 9 between the motors! It may help to tin the wire ends before soldering!

(You may want to make the connection to the motor temporarily with an alligator clip in the next step)

11. Power up your beetlebot!

First, look at the wires coming out of your battery holder. One wire is + or Positive connection! One wire is – or Ground/Earth connection!

You may want use three alligator clips to test circuit before soldering. Tin the end of the Battery holder wires, then solder to the switch as shown!

Test your Beetlebot:

Put batteries in it. (Alligator clip the third Battery holder connection to the motor for now!) Both motors should turn.

By pressing the l e f t switch the l e f t motor should turn the other way. By pressing the r i g h t switch the r i g h t motor should turn the other way.

12. The Antenna Holder! Get your terminal connectors. Remove the plastic end of the terminal connector. Take pliers and flatten the end of the terminal connector so you can slide it tightly onto the lever of the switch!

13. Antennas! The antennas are the Sensors of the Beetlebot.

Use Paperclips to shape the Antennas. Shape & Tilt of antenna Matters!!! Solder the paperclips to the antenna holder.

If you want it to look pretty, put some larger diameter heat shrink over the connection.

14. Making the Switch connection

Add a switch as shown to allow you to turn the Beetlebot on and off without removing the batteries! Putting heat shrink on before soldering to the legs will help aesthetics, but also keep your solder joints

from shorting out in such a small space!

15.DECORATING YOUR BEETLEBOT

Get Creative. . . you can make yarn pom poms, use googly eyes, cut foam for the body, use clay to shape things, you can even use scrap vinyl Or Sponges with felt.

Attaching to the Beetlebot: you might want to try a magnet approach so you can take off the cover and

show others the electronics and your beautiful soldering

16. Troubleshooting Unless you are VERY VERY LUCKY, Your Beetlebot will not work perfectly the First time! You will have to

make some adjustments!

Antennas:

You can modify the angle and the “curl” of the antennas to make the Bot more responsive

Motors: You can modify the position of the motors to make them more parallel and more balanced

You can modify the heat shrink to make it more even You can change the position of the motor mount (easy if you used masking tape)

PLAY WITH YOUR BEETLEBOT AND ADJUST IT!