This is a must-do hack for any cheap R/C car, it uses the tilt sensing switches I made so you can control a car just by tilting the controller like a wiimote.

There are many possibilities with this hack, for example, you can turn the controller into a base-less joystick, or put it on a helmet and control it with your head.

this will also work for R/C tanks (or other two motor drive stuff) except the switches needs to be placed diagonally

Another possibility to explore is making a mini segway, if you can get the tilt switch sensitive enough and the controller mounted onto the car (the car must be wheelie-ready). This might not work so good.

Below is two pictures of the car I'm working with (the front end spins, not steer, but it is not a problem with some practice)

You will need:

r/c car
tilt sensing switches (see step 2)
hot glue gun
soldering iron
wires
some pvc pipe (see step 4)
collection of hand tools

Demo Video:

Step 1: Making the Tilt Sensing Switch

I made another instructable before, just for this switch
Click Here To See It

But I had to adjust the switch by drilling more holes into it until i got it just right.

The second picture shows how it works.

Step 2: Opening and Testing the Controller

First you need to figure out how the controller works.

Open it up, save and map out each screw
If your antenna wire is moving around, hot glue it down.

You need to use a multimeter to test what connects to where, have fun at it. What I found in my controller was 4 metal flaps, all connected together, which presses against 4 jumper wires underneath them. The 4 flaps are connected to the negative terminal of the battery, this makes it really easy to hack.

You might also have one with buttons instead of sticks, I have no idea how those work so you need to figure it out.

If you are unlucky, and each flap or button are not connected to all the other buttons, then you might need to use 4 tilt sensing switches, except make them SPST.

DO NOT BE TEMPTED TO DO ANYTHING TO THE COIL THINGY

Step 3: Adding Some Wires

Now you know what needs to be connected to what, solder some wires to those places. (colours of the wires doesn't matter)

Now try and control the car by touching the wire ends together, if it doesn't work, figure out why, it could be a simple bad solder joint.

Drill some small holes so the wires can get out, put the wires though them, take care making sure that the wires won't be bothering any of the mechanical parts inside the controller (such as the stick or the metal flap, or stopping the casing from shutting completely).

Close the case, test it again by connecting the wires and by using the sticks, it's better to have both of control methods working.

If you want to make the controller one big base-less joystick, cut a large dowel (or pipe), and attach it to the top or bottom of the case before you close the case. Make sure everything fits.

Below are three examples of what I soldered

Step 4: Mounting the Switches

If you are lazy, just attach the switches to a block of wood.

What I did made it completely adjustable, you need:

*3/4" pvc pipe
*3/4" pvc pipe cap
*1/2" pvc pipe
*some tape

Put the tilt switch that will control the forward/reverse on to the face of the 3/4" pvc pipe cap.
Cut a segment of 3/4" pipe, and drill 2 holes for the antenna to go through, and in my case, one of them might need to be bigger.
Cut a small stub (1-1/2" to 2" long) of 1/2" pipe, attach the steering tilt switch on the side of the pipe
Put lots of tape on the 1/2" pipe stub, and insert it into the 3/4" pipe, it should fit snuggly
Put the 3/4" cap with the tilt switch on the other end of the 3/4" pipe
Put the entire assembly onto the controller

This way lets you adjust the switches every way possible

Look at the diagram and pictures if you get confused

Step 5: Hooking Up the Switch

You might have noticed I put spade connectors onto the switches, you can do this too, but you don't really need to.

Wiring is simple enough, loop the wire around the screws and then tighten them.

If you have one wire from the negative battery terminal like me, put a switch on it, I would but I didn't have any switches handy.

Step 6: Testing, Calibrating, Finishing

Now if everything was done right, it should work, so test it, and if using it feels awkward, then rotate the switches until everything feels balanced when you are driving.

You are done.

Step 7: Mini Segway Idea

This is just an concept

If you have a car like mine then you can try making a more sensitive tilt switch and mount the controller right on the car mount it in a way that the switch is neutral when the car is almost balanced on its rear wheels
If the car leans forward, the the switch will make the car move forward, making it lean back
if the car leans back, the switch will make the car move in reverse, making it lean forward.
If everthing is balanced, theoretically the car will remain in place and balanced on its rear wheels
If the front is slightly heavier, then the car will start to move forward slowly while trying to stay balanced
If the rear is slightly heavier, then the car will start to move backwards slowly while trying to stay balanced

This will only work if the car doesn't over react and the switch works fast enough.