How to Build a Brushbot


[whoosh] [ding] Hi, this is Ben Finio with
Science Buddies and this video will show you how to build a brushbot using your Science
Buddies bristlebot kit. To build the robot, you will need a double A battery pack, two
double A batteries, and a motor, supplied in your bristlebot kit. You will also need
some other supplies not included in your kit. Scrub brush, a cork, some double sided foam
tape or a hot glue gun, and electrical tape, although you can also use regular clear tape
or duct tape. To start building your robot, you will assemble a circuit by connecting
the batteries to the motor. Before you start, make sure the power switch on your battery
pack is in the off position. This will help prevent accidental short circuits which can
make the battery pack get very hot. Next, flip the battery pack over and use a small
Phillips head screwdriver to remove the screw that’s holding on the cover. You can place
this screw aside because you will not need to put it back. Next, press down and slide
the cover off the battery pack. Take the two double A batteries and insert them into the
battery pack. Make sure that the plus signs on the batteries line up with the plus signs
printed inside the battery pack. Another way to check is to make sure that the flat end
of the battery lines up with the spring. Once you’ve inserted both batteries, slide the
cover back on until it clicks into place. Next, you will create a circuit by connecting
the battery pack wires to the motor wires. You do this by tightly twisting together the
exposed metal ends of the wires. Now normally in electronics, red stands for positive and
black stands for negative, and it’s important to get these wires matched up and not mix
up the color coding. In this case it actually doesn’t matter because if you reverse the
wires, it will just make the motor spin in the opposite direction, but it’s still good
to get in the habit of color coding your wires. So we’re going to take the red wires and tightly
twist together their exposed metal ends. Now you see if I don’t really do a good enough
job twisting them together, those will come apart very easily and then when my robot starts
vibrating and moving around, the wires will come loose and it will suddenly stop working.
So you really want to make sure you twist these together tightly enough that you can
tug on them slightly and they don’t come apart. You can see now I’ve done a better job twisting
those and I can even lift the battery pack by the wires and it won’t fall. Now you’ll
notice if I turn my battery pack on, my motor does not spin. That’s because right now I
still have an open circuit. Electricity needs a complete loop or path to flow from the battery
pack, through the red wires, through the motor, and then back to the battery pack through
the black wire, but I haven’t connected the black wires yet. So next I’m going to do the
same thing, and tightly twist those black wires together. I’m making sure that I do
it tightly enough that they don’t come apart if I tug on them. And now I have a closed
circuit, so if I turn my battery pack on, I should be able to hear the motor spin [whirring
noise]. It’s a little hard to see the motor spin though since it has such a thin circular
shaft, so this is where I’m going to take my cork and press it on to the motor shaft.
Press firmly, don’t be afraid to break the motor, get the cork almost all the way onto
the shaft, but not pressed so far up against the motor that it gets stuck and prevents
it from spinning, and now, hold onto your motor tightly, turn your battery pack on,
the cork will spin and the motor will vibrate. This is what will power your robot and make
it move later. Now remember that we mentioned earlier that short circuits are bad and can
cause your battery pack to overheat. And you can get a short circuit while your robot’s
moving around if these exposed metal parts of the wires bump into each other. So to avoid
that, cut two small pieces of electrical tape, or if you don’t have electrical tape you can
use regular scotch tape or duct tape, and tightly wrap them around the exposed metal
parts of the wires so no metal is showing. Now the entire wire is covered in insulation,
so even if these sections bump into each other you’ll be protected from short circuits. So
do that tightly with both wires. So one thing to be careful about now that you’ve assembled
your circuit is how you treat the wires. Remember I did say you want to make sure that these
twisted connections are nice and tight so you can pull on those a little bit and they
won’t come apart, but you do want to be careful with the connections to the battery pack and
especially the motor. If you pull on the wires too hard or bend them back and forth repeatedly
you can actually break these connections and the metal on the inside might break while
the external insulation stays intact. So you won’t actually be able to see the break and
your motor will suddenly stop working and you won’t be sure why. So, make sure that
you keep these wires coming out straight from the motor, don’t bend them over 90 degrees
and don’t pull really hard at these connections and you should be OK. Now to assemble the
body of your robot, cut two pieces of double sided foam tape and press those down onto
the top of the scrub brush, one sort of in the middle or towards the front, and then
the other one towards the other side. Make sure you press down firmly so the tape sticks.
Now take your battery pack, press it onto one piece of tape, and then take your motor
and press it onto the other piece of tape, and you have to be careful with the motor,
make sure that the cork can spin completely without getting stuck against the brush. You
can see there, I actually didn’t do a very good job mounting that because the cork sticks
against the brush and it won’t be able to spin completely. So there are two things I
can do. I can pick the motor up and move it a little farther out, but I’d rather have
my motor have good contact with the tape there. You can also take the cork off, and press
it back on at a slightly different angle or maybe make sure you don’t press it on as far
to there, I’ve made sure that my cork can rotate completely. Now, if I turn my robot
on [buzzing noise] uh oh! You can see I didn’t really do a good enough job mounting my motor
there. The vibrations were so strong that it knocked the motor right off. So I have
a couple different options to make that better. If you have a hot glue gun and adult supervision,
because hot glue guns can get very hot, you can use a big blob of hot glue, which will
help the motor stick on a little better. Or if you have more tape like electrical tape
and duct tape, you can wrap it around the top of the motor to really secure the motor
on there much better. So here I have my modified brushbot where I have a nice big blob of hot
glue holding the motor on, you can see that does a better job holding it in place [buzzing
noise]. You can see I have also added some googly eyes to the front for decoration, you
can decorate your brushbot however you’d like, and remember if you don’t have a hot glue
gun you can just wrap additional tape around the top part of that motor to hold it on nice
and tightly. Be careful when adding decorations and glue and tape that you do not accidentally
tape your battery pack shut. You will need to be able to slide off that top part eventually
to replace the batteries, so make sure you don’t glue or tape those two halves together.
And once you’re done, you should have a working brushbot that you should turn on and it will
dance and vibrate and move randomly around the table. There are a couple other things
you can try with your brushbot kit. You can challenge yourself to try building a robot
that goes straight, we won’t give away the secret for doing that but a hint is that it
has a lot to do with the shape of the bristles and the direction in which they’re slanted.
Your kit contains enough parts for two brushbots so you could have a friend build one and you
could race them against each other, or you could even sumo wrestle them. And finally
you can build another type of robot called an Art Bot that uses the same circuit but
has markers for legs instead of bristles so it will draw a picture when you put it down
on a piece of paper. Good luck and have fun. To purchase a bristlebot kit, or view directions
for this or thousands of other science and engineering projects for school or at home,
visit us online at www.sciencebuddies.org.