Used remote control (RC) cars (boats, hovercrafts, planes, and quadcopters too!) are often easy to get. If not totally free, you can at least get one cheap. Find yourself an RC car and its controller. Plenty of kids have at least one collecting dust somewhere under the bed or in the closet. Help a friend tidy their room by offering to recycle their electronic waste! Or hunt one down at a yard sale or thrift store for $2.99. An axle might be bent, a wheel might be missing, or a gear might be worn down, but the brains of the system usually work just fine. You can control that brain and hook it up to whatever you want! Dream big!
Step 1: Make Sure It's Ready to Obey You!
The goal is to gain control over something simply by moving your thumbs...so let's make sure your controller is able to communicate with your car. Give the car and controller the voltage they want*, then move the toggles and look for activity. Even if the car just clicks or buzzes, that's usually a good sign! Your car is at least trying to obey you, but maybe it simply can't. Imagine that your mom told you to clean your room but you have a broken toe and a broken finger. You are listening and ready to obey, your brain is telling your body to move, but a mechanical part of the system isn't working correctly. This instructable is all about replacing that mechanical part of the system...with whatever you want. Even something non-mechanical! Wha?
*If the required voltage isn't written anywhere, you can usually figure it out by counting how many spaces there are for holding a battery. 9v batteries are...wait for it...9 volts! All of the "alkaline" cylinder shaped batteries (AAA, AA, C, D) are 1.5 volts each, so count how many are supposed to be connected head-to-tail and add them up! For example, if your car takes 5 AA's it probably wants 7.5 volts! (Oh. By the way, the red wire is probably the positive and the black one negative.)
Step 2: Crack It Open and Find Out What's Inside
This is where the fun really begins.Take out any screw you can find that seems to hold the bottom of the car (where the wheels are) to the top of the car (the part that makes the car a Camaro or a Hummer). I had to remove 12 screws. Be careful when separating top from bottom because there might be wires still connecting them. In my case, there was one red wire...that seemed to go nowhere! Wha? That's the antenna! If I had yanked things apart, the antenna wire might have pulled out of its place on the circuit board. Even if I'm good at soldering...I may have a lot of trouble figuring out where it was supposed to go. And without it I may have a wireless range of only a few inches...not very "remote" control...
*Some screws are hidden beneath stickers, so if it seems like they're all out but the car still won't come apart start peeling stickers away. Sometimes stickers even hold things together!
Step 3: Figuring Out What Goodies You Have to Work With
At this point you likely can identify some components to your system. There should be a circuit board (or more than one connected by wires), an on/off switch, and likely two* motors, gearboxes, or servos. The motor is the main thing in the system that causes physical action to come from your command. Motors are metal grey-colored cylinders and they may be hidden inside--or half sticking out of--a plastic casing. This casing is the gearbox or the servo. The guts of these casings either turn the fast rotational motion of the motor axle into the right amount of rotation for your drive wheels OR they turn spinny motion into side-to-side motion to steer your wheels. You may be tempted to remove the motor from its casing, BUT WAIT! Depending on what you may want to remotely control--these things may be exactly what you need.
*Some cars only have the ability to control only one thing--the rear wheels (the front wheels are either stuck in their straight position or they turn as a result of rolling backwards.) Don't worry, you still will have the ability to control at least one thing with only your mind and your thumb!
Step 4: Imagining the Possibilities
By now you might have felt the uncontrollable urge to take out the screws that held the components to the frame or "chassis" (pronounced CHAS-EE). Good instincts! Just don't dig into those casings that hold the motors. First we want you to take a moment to think about the endless possibilities. Go ahead and take the opportunity to power things up again. Figure out what the controls on your remote are doing now. For me, one of my joysticks moves an arm on the servo back and forth. The other joystick spins the wheels. Don't let this mess of interconnected parts pull itself right off the table at this point like I did!
Now think...servos can move things back and forth...but they can also flick switches and push buttons...in other words, anything that is operated by a switch or a button can now be controlled by your invisible force! And don't restrict yourself to thinking that wheels need to only roll on the ground--they can also pull on ropes and lift things up!
Step 5: Think Outside the Box
By now you should've decided if the mechanical parts your car had when you got it--in my case a working servo and a working gearbox--is what you need to realize your vision. Maybe you'd like to explore other options. Unless you have other lights and/or noisemakers, your circuit board should have two wires going to the on/off switch, it should have two wires going to your power supply, it should have an antenna, and it should have two wires going to each thing that's responsible for motion. These pairs of wires are what give the gearbox, servo, or motor, their energy at your thumb's command. These pairs of wires can be thought of as being connected to your battery, but through electronic switches, called transistors, which are able to connect, disconnect, and even flip the polarity*--hooking positive where negative was and vice versa. Again, what these switches are doing all this depends on your thumbs!
Since my power supply was 9 volts, its a pretty good guess that 9 volts is what these wires supply, and the polarity depends on the direction of the controller.
With all the excitement of taking things apart I was feeling like having a dance party, so I decided to snip the wires to the servo and hook up lights to my wires. Three LED's is about 9 volts. It worked...and luckily they lit up only when I told them to.
I'm feeling the power of remote control. What kind of mischief can I get into now?
*Polarity is simply about which way you connect positive and negative.
Step 6: More Brainstorming...
At this point I know I've got 9 volts, on whatever I want, to turn on and off (or switch direction). And I have that ability on two sets of wires. I could hook up any combination of these things: light, buzzer, electromagnet/solenoid, motors...the list goes on! The sky is the limit! Enjoy tinkering!
Step 7: Possessing Other Electrical Things
Let's not limit ourselves to engineering things from the ground up...especially if you're getting frustrated. Work smarter not harder. How about tapping into components that are already embedded in other systems? There are small DC motors in many other battery powered things. The wires are easy to snip, strip, and twist to your own wires. And your circuit board and battery are small enough to hide inside...if you want to be sneaky about it. This allows you to "possess" things, as if by mind control, to amaze your friends and family!
Here are some suggestions for fun things to possess.
- dead furby
- singing fish
- fan-powered bubble blower
You can even keep changing it up. Have fun!
Step 8: Some Inspiration
DeKwan piloted our RC hacking program to make sure it would be fun and fruitful. He is able to innovate to his hearts delight because he has access to lots of junk! In this video he tries a few different approaches as he inches closer to perfection.