Hi there! I am 13 so I will be entering the Robot Contest for the 13-18 age group! This robot is the simplest thing I have ever made. It is intended for anyone who has very little experience with electronics. You'll learn how to use switches and motors! You won't need a whole bunch of parts from electronic stores either! Most of the parts are found in your house! It has three wheels and basically just goes straight! You can find so many uses for such a simple robot!
Step 1: Materials!
Parts (Mostly in your house)
-A base- This is used to hold everything together. I used a piece of cardboard from a box getting thrown away. You could use plastic or metal or whatever!
-Two Electric DC Motors- These can be found in most anything that spins! Fans, pencil sharpeners, RC Cars. Try to make sure they're the same size, although that doesn't mean they're the same.
-Two AA 1.5V batteries- Both of these will supply three volts to the motors.
- Bottle Caps- You don't exactly have to use bottle caps. Anything round you can find to use as wheels! Bottle caps don't have the best traction, although they work on short carpet!
- Some Tooth Picks- These are used as the axle for the front wheel.
- A Two Position Switch- These have three pins. I will describe them more later.
- Some Wire- To connect the batteries to the switch to the motors.
- NOT IN THE PICTURE- 2 Popsicle sticks. These are used to attach the front wheel axle to the base of the car.
A Hot Glue Gun- Used to hold everything together. NO SOLDERING! Use the Hot Glue Gun with caution!
Hot Glue- Kind of implied but I thought I'd say it anyway!
Clippers or Scissors- Used to cut everything from the wire to the cardboard.
(Optional) Wire Clippers- Very helpful to making wire connections.
A Drill Press- (Or Something sharp to make a hole.) This is to drill the wheels to go onto the motors!
A "Holder"- Something to hold a tooth pick up so you can use both hands. This could be another person.
Step 2: Drill the Wheels!
First, drill a small hole in your wheel (Bottle Cap) so it matches the size of the shaft of the motor. It can be a little off, hot glue will fix it later. Once you have drilled both of the back wheels, drill your front wheel of choice. Mine was on wheel from an RC car that alread had a partial hole. But you can use anything round! For the front wheel put the tooth pick in to make sure it is not too tight. If it's too tight, it won't roll. So, now you should have three wheels of some sort with a hole in the middle of each.
WARNING: If you are young or inexperienced with a drill press, ask someone for help!
Step 3: Add Wires to the Motors
If the motors you got already have wires connected to them that are about 5 inches long, your all set. But if you don't, it's fine. Grab some wire from whatever you have. It's great if you can use two of the same different colors on each motor (ie, red and black on each motor or blue and white) so you don't get them mixed up later on. So, once you have your wire, wrap the end of each wire on the small metal leads. Make sure you make a connection between the wire and the leads. Squeeze it tight so it's connected. Now, use your hot glue gun and glob some glue on top of the connections between the wires and the leads. Once it dries connect each end of the wire to a battery and make sure the motor moves. This is confirm there is a connection.
Step 4: Attach the Wheels!
Now since we have the motors ready, we want to connect the wheels to the motors! First grab your hot glue gun and plug it in, you will be using it again. Then position the motor shaft inside the hole in the wheel. Do not put it so far that the wheel is rubbing on the motor. It will slow it down. Once you have it positioned to your liking, put a dab of hot glue on the shaft poking through the hole. This should secure the wheel to the motor and it should not move without moving the motor.
Once you have both of the front wheels done, set them aside and grab your toothpicks, hot glue gun, and popsicle sticks. First cut the popsicle sticks according to the size of your wheel size. Measure from the center of your wheel to the outside of the wheel. Double that number and make that how long your popsicle sticks should be. Cut four sticks that size. Once you have those four, clamp your toothpick straight up and down with something. Grab two of those sticks and position them like in picture number 5. Then shoot some hot glue in there. Hold those and wait for them to dry. Now put the front wheel on the toothpick! DON"T FORGET TO PUT ON THE WHEEL! Then repeat what you did on the other side to that side. Then it should look like picture 7.
Step 5: Attach the Motors to the Base
Again, plug in your hot glue gun, you'll be using it. First, line up your motor with the wheel to where you want to put it. Use pencil to mark where the wires will be going through the base. Then, use some scissors to cut out the area that you marked. Now, grab both of your motors and a battery. By reversing the wires going to the battery (+ and -) determine which way the motor turns and mark on a piece of paper or something which wire (ie, red, blue, etc.) goes to the + of the battery and which goes to the -. Once that is finished and you know which way to put your motors, put them in the holes you cut and feed the wires through the holes. Then grab your hot glue gun and douse it with glue. Put it on both sides of the motor to secure it so it doesn't fall off. Once both have dried, it should look something like the final picture above.
Step 6: Attach the Front Wheel to the Base
This is probably the easiest step! All you need to do is set the four legs of the front wheel onto wherever you want it on the base. Then put some hot glue on that and let it dry. Easy peasy, lemon squezy.
Step 7: The Wiring
You might think this is the worst part, but it is quite fun! So you'll need to grab that battery holder and the switch. First, the battery holder has two metal leads on it near the bottom. There is a positive lead and a negative one. The negative one goes directly to the - of your motor. You can go ahead and use two pieces of wire and attach one to each lead on the battery holder. Once you have them on there with hot glue, hot glue the holder to the base.
The Switch- The switch has three leads coming out of the bottom of it. Above is a drawing I made of one. The goldish color represents conductive material, which mean electricity can flow through it. The top black part of the switch (that you move) is connected to the large conductive piece. When you move the switch to the left or right, you are connecting either the left two leads or the right ones, allowing electricity to flow through it. So if we want the switch to control the electricity going to the motors, we need to put the positive wire coming from the battery holder to one of the end leads. We also need the motor connected to the middle lead. So I put my battery on the far right lead. So, when the switch is to the left, it is connecting the motor to nothing, so it will not run. But when it is to the right, it is connected the the battery which supplies electricity and both motors move.
I have made a small diagram showing where all the wires go. It's very easy to read. Red lines are wires. Connect all the wires by twisting them together and then putting some hot glue on the connections.
Step 8: Your Done!
Wow! Your already done! It shouldn't have taken you that long, I built this in about an hour. I actually ended up using two different motors on accident so it kind of just goes in circles. I also reversed the + and - on the motors, so it goes backwards (I learned from my mistakes!) I was thinking what I could use a robot that goes in backwards circles for then it came to me, a cat toy. Enjoy the video. But now you can you your imagination to use it however you want! I hope you learned a lot and had fun building this! Thanks so much for reading, and please vote for me in the Robotics Week Challenge. By the way the Robotics Week challenge was about making the simplest, easiest, re-using objects for parts, robot. So if you believe that's what this is PLEASE VOTE!! Thanks!!!