What you'll learn:
How to make a drawing robot.
Robots aren't just those we can control with chips. Brainless robots can also do fun things, like create robot art.
Building a drawing robot with your kids is a great afternoon project that will end in lots of squeals of delight. Kids will have a chance to learn basic circuit building skills, like how do we connect a motor and a battery so it will run, as well as engage in some engineering and design. You will need a few ingredients for this drawing robot, but a lot of the list can be found at your local dollar store.
Seriously, the dollar store is my #1 go-to for things like markers, tape, batteries, cups, erasers, and even foam stickies. It is how I manage to keep the supplies of my classes down - in fact, I managed to create these drawing robots for about $1 each in total! If you want to build bigger and better robots, you should check out our robotics for kids post.
Markers (you'll need 3-4 per drawing robot)
DC motor or DC motor kit (get the kit if you want a switch and battery holder)
Wire (if you didn't get the DC motor kit)
Electrical tape (the dollar store has two big rolls for $1)
AA batteries (again, the dollar store has 8 for $1, they aren't quality, but they are great for little projects like this)
Foam stickies (optional)
A note on your drawing robot
In my classes, I have a lot of kids who get frustrated because they want their drawing robot to go forward, or spin more, or make dots instead of lines. It is important to reiterate that this drawing robot is a ‘zombie’ robot – a robot without a chip. We can’t control chipless robots, but we can experiment with changing angles, weights, and locations of items to see how that affects the drawing nature.
How to make a drawing robot
- Add wires to both leads of your DC motor and wrap with electrical tape
- Push an eraser to into the DC motor axle
- Test the DC motor by placing a single AA battery between the two wires
- Add marker legs to your cup
- Attach the motor and battery setup to your cup
- Create robot art
1. Add wires to both leads of your DC motor and secure with electrical tape
Some electronics projects can feel overwhelming if you need to pull out a soldering iron. Thankfully, this isn’t one of those projects. Strip a half inch section of wire, thread it through one of the metal holes and twist the wire to secure it. After you have done that for both sides wrap electrical tape snuggly around the DC motor to keep the wires in place. I find if you also tape the wires to the sides of the motors it helps maintain connection better.
2. Push an eraser onto the DC motor axle
The drawing robot is able to move because of intense vibrations. These vibrations make the markers scuttle from side to side, allowing your robot to draw. You will notice that the DC motor axle is very well centered. In fact, if you plug a batter between the two leads you will hear the axle whirl but you won’t really feel a thing. To change that we can mount a weight onto the axle. As the axle spins the weight will swing around and cause the vibrations. I have found the easiest way to add a weight to a DC motor axle is just with a simple eraser.
You can get silly erasers or just use the standard pink eraser, but you want to push the eraser onto the axle off center (so the weight when spinning creates vibrations). You will have to push very hard, but by doing so you create a surprisingly secure connection between the spinning eraser and the axle.
3. Test your motor with a single AA battery
It might be tempting to use a 9V battery with your DC motor, but doing so will cause you to smell the overheating motor parts dying. In fact, a single AA battery will provide more than enough power to spin the eraser of your drawing robot. It doesn’t matter which way you plug the AA battery in, but you can experiment with switching the leads on the battery to see what happens to the spin of the motor.
I like to permanently tape one lead onto the battery, and make it easy to connect the second lead using a piece of tape. This allows you to have a very simple switch. I also like to take the battery to the DC motor (in a way that doesn’t block the spinning eraser), to reduce vibrations in the wires. If you just let the motor or battery pieces dangle the vibrations will cause all of your connections to come loose and your drawing robot to stall out.
4. Add marker legs to your cup
This is a fun little engineering problem. How can you attach the three markers to your cup so that it will still stand up? If you have lots of trouble you can try using small pieces of tape to situate the markers, then large pieces of tape to hold them down. Aim for using 3-4 markers. Using more will cause your drawing robot to be too heavy to move around well.
5. Attach the motor and battery setup to your cup
At this point, you should have a cup with markers, and a motor that vibrates. To create the drawing robot we need to merge the two. Careful though! where you add the motor is important for a few reasons. The weight can cause your drawing robot to fall over, and some locations will prevent your eraser from spinning!
6. Create robot art
Tape the second wire to the battery to start your drawing robot up and see what happens! Remember, since this is a zombie robot, or a robot without a control chip, we can’t predetermine the types of drawing and art it will make. You can tinker with weight distributions to see how it affects the drawing style, however.