This is a remote controlled Halloween project. It can squirt water at you, then dry you off with a cordless blower, swing arms out to "grab" the kids that take too much candy, and a walky-talky through a PA to let them know what the clown is thinking. The clown and the truck have LED eyes and a strobe light making the clown a little more creepy. Its all remote controlled and I have most of the steps documented.
I have a video of it on youtube http://www.youtube.com/watch?v=fo3YHKa_hco
Step 1: Driving and steering your powerwheels
This has always been the most difficult part but I have done enough to know now that a linear actuator is by far the best thing to use for steering. A linear actuator from ebay is about 40 - 50 dollars if you look long enough. One with a two inch stroke will do. From another project I had a sabertooth 2X25 that will control the steering with one side of the motor controller (sabertooth) and the other side will control the existing drive motors on the powerwheels. Sabertooth motor controllers are very easy to work with. Wire both drive motors together and screw them into one side of the sabertooth and then land the other two wires from the linear actuator to the other side of the sabertooth. Now hook up the signal wires from the sabertooth to your receiver and you're almost ready. (Hobbypartz.com has a really inexpensive 6 channel 2.4 transmitter and receiver)
Step 2: Wiring the Powerwheels motors
Wire the sabertooth ground terminal (GND) to the battery ground, and take the positive lead of your battery and wire it into a 50 amp switch. (cheap from autozone, 3.99) Make sure the switch is off and wire the other terminal on the switch to the +V side on the sabertooth. The sabertooth has a 5v regulator built in so you do not need anything else but to connect your receiver to the S1 S2 Gnd and 5v on the back of the sabertooth. Two servo pigtails are meant to do this easily, the middle wire always being the +5v.
Step 3: Rotating the Clown
You should now have a driving and turning RC powerwheels car. If you have a 6 channel remote control, you still have 4 channels left to do anything you can think of. I used one of them to make my clown turn to look at people. (He actually turns to point the water pick gun at people). I had a right angle motor from a surplus store. This is in the picture below and I made a PVC adapter and set screwed it to the motor shaft. Then I used PVC pipe for the clowns torso and this fits right into the motor shaft adapter. For controlling this I used a sabertooth 2X10 RC. ( I know you think this is too expensive and it is if this is all you're doing with the components, but I'm sure you will think of other uses. I have used these parts on 25 different projects and just keep rotating them from one thing to another.) Wire this the same way you did the drive motors and wire the power through the main switch like with the sabertooth 2X25. This way everything turns off with one switch. I used the rudder channel of my RC controller to turn the clown left and right. The other side of the sabertooth 2X10 will be used later. (for the arms)
Step 4: Water Gun
Next I added a water pump from a 12volt sprayer. This is wired directly to the ground of the battery and through the switch, just like the other two sabertooth motor controllers. The output of the pump runs up to a 12 volt solenoid valve on the back of the clowns head. The other side of that runs through the clowns mouth. The solenoid valve ground wire goes to the battery, and the positive wire (red wire) goes through a relay switch (8 channel buy from ebay). These are great components, you can get a 8 channel relay switch with 8 channel remote control for about 20 dollars. The other side of the relay goes to the main battery positive side. When the relay switch is activated the solenoid valve will open, letting the water pump shoot the water out of the clowns mouth. The pump needs a resovior of water to pull from, so I used an empty paint can that I could cut a hole in the top and feed the water hose through.
Step 5: Arms
Now on to the arms. I used two right angle gear motors that were surplus from car seat adjustments. They are approximately 100 RPM so i knew that was going to be way too fast with such long arms, but the motors seemed to have enough torque to get them started and really whip. It turned out to be better than I hoped (hardly ever happens like that). Both of these motors are wired back to the sabertooth 2X10. I used the throttle channel on my remote to control these, push the stick forward and they sling out, pull back on the stick and they come back into the parked position. Here again one of the hardest parts of making projects like this is to find a way to attach your moving parts to your motor shafts. I used a dremel tool to grind a flat stop on the motor shafts and used two lock collars to setscrew them to the shaft, then bolted the PVC arms to the collars. To make the pipes conform to the body of the powerwheels I heated the pipe up (with a blow torch) at a single spot and it bends super easy. Hold it in place where you want it until it cools.
Step 6: Cordless Blower
I put a cordless blower into the powerwheels to blow air into the kids faces. I used the existing battery that comes with them. Connect the ground terminal to the ground terminal on the cordless blower, connect the positive terminal to one side of a relay on your 8 channel relay switch and then the other side of the relay goes to the cordless blower terminal. When you close the relay you will turn on the blower...just make sure to cut the switch on on the cordless blower. Its a little hard to see in the picture but I used a short hose to direct the air from the blower out the front of the windshield of the powerwheels.
Step 7: Chomping teeth
The chomping teeth on hood were really easy to make. I put a small hinge on the hood and put a slow turning (30 RPM) motor inside the hood with a short piece aluminum channel bolted to the motor output shaft. I wired the motor through the relay switch and when you close the relay the motor starts running and the aluminum channel hits the hood pushing it up, rotates, the hood falls down and about that same time the motor has made another revolution and lifts the hood back up again. The teeth are foam insulation from Home Depot and held in place with some real duct tape. With a little paint they start to look like teeth.
Step 8: LED eyes
I added LEDs into the clowns eyes to make him seem more creepy. I used some LEDs bought from hobby partz that will take 5volt input to make them glow. Remember how the sabertooth motor controllers have built in 5volt regulators, well simply plug the LEDs into your RC receiver and they will turn on when you turn on the main power switch of the powerwheels. I drilled holes through they clowns eyes and fished the wires through and all the way back down the clowns torso and into the receiver. I used more foam to cut out some scary eyes (my art wife had to help me there) and put LEDs in them as well.
Step 9: Scary Clown Laugh
I had a set of walky-talkys and kept one with me inside the house and put the other one in the powerwheels. I used a PA horn bought from ebay several years ago and got a 1/8 stereo plug connector that fits into the output plug of the walky talky. I had downloaded several scary laughs on my phone and would play them through the walky talky to the powerwheels. This really did seem to work well.
Step 10: Hope this helps
I hope this gives someone ideas for next year... Send me some better ideas