Introduction: Make a Fire Breathing Animetronic Pony From FurReal Butterscotch or S'Mores

For Maker Faire Detroit 2011, I displayed a hack I made to a FurReal Friends Butterscotch Pony. My fellow LVL1 Hackers and I had taken control of the motor control system of the toy and added a flame thrower to it.  It seemed to go over really well with the crowd, so I am putting up the information for anyone to make there own.  It was a blast to make and I hope everyone has as much fun remaking it.  Just remember that this project uses Fire and should only be built and operated by no less then 2 adults with appropriate experience in fire safety and proper fire safety equipment on hand. 

Step 1: Get It Before You Hack It

At one time, Butterscotch and S'more ponies both sold for around $300, but they seem to be discontinued.  I would  never suggest someone pay this much for something new, just to make it better. Thankfully, there is a fairly steady stream of them showing up on Craigslist and second hand stores.

I purchased my first Butterscotch off of Craigslist for $20.  I have since picked up a second one for $25 from a peddlers mall.   I commonly see them listed for ~$100, but with a little negotiation and/or patience you should be able to pick one up for dirt cheap.

Step 2: What You Will Need.

The tools you will need vary in this project.  I will try to tier it based on what you want to accomplish with your FurReal pony.

Hardware you will need:
  • FurReal Butterscotch or S'More Pony
  • Arduino Mega
  • Wire 18g
  • Solder
  • Electrical tape
  • Wii nun-chuck
  • Wii Nunchuck breakout adapter
  • 0.1" 16-pin strip male header
  • 1/8th OD ptfe tube (trade name Teflon)
  • Bowden cable (brake cable for the back wheel of a bike)
  • Scrap PVC tube around 3" at about 1' long
  • Scrap plexi glass

Tools you need
  • Wire Strippers
  • Razor blade
  • Phillips head screwdriver
  • Flat head screwdriver
  • Multimeter
  • Soldering Iron
  • Computer to program the Micro Processor (Any OS)

Step 3: Removing the Skin: Head First

Before you get into the really fun parts,  you will need to skin your pony.   I started at the head as it already has a zipper.  Move the mane out of the way, and locate the zipper at the base of the neck.  You will find that the zipper pull has a cap over it to prevent it from unzipping.   Simply break off this cap and unzip the skin from around the head.

Step 4: Removing Skin: ENT

Now we are going to remove the skin from around the face.  The face is attached in 4 areas: the ears, eyes, nose, and mouth.  Pull the skin up the back of the neck so you can get inside the back of the ponies head.

The ears break off easy (one was already missing when I got to this point). The other broke off when I was trying to get the skin off.  This is not a problem as you can glue them back on easily.  If you wish to keep the ears attached, you can cut the cloth around the ear holes with a razor.  If you are OK with taking them off, a hard tug should pop them right off. Once the ears are removed, pull on the fabric where it tucks into the head. This will rip the seams, freeing it up.

Roll the skin further down, and you will get to the eyes.  The fabric is sewn into the top and bottom of the eyes.  Simply cut the stitches here to detach the fabric.  Try to not look your pony in the eyes when you do this, as you may start feeling bad about what you are doing.

Moving down to the ponies nose, there are 2 pegs holding the rubbery snout on.  One in each nostril.  These slide out without much trouble, away from the body in a parallel fashion.  The rubber on the snout is thin, so try to get a grip on the hard plastic with your tool as not to tear it.

Step 5: Remove Skin: Straight From the Horses Mouth

The last step of peeling your ponies face off is to removed the skin from the mouth.  The the skin on the upper and lower jaw are both connected in their own way.

To removed skin from the upper jaw you just need to fold the face down until you see a horse shoe shaped piece of plastic around the mouth.  It will have 4 pegs pushed up into holes with 3 legs that close around them.  You will just need to bend 2 of the legs on each peg back and they will pop right out.

The bottom jaw will most likely have popped off by this point.  We need to remove the jaw plastic from the rubber.  It for the most part will pill off but it will take some time.  I also had to cut some spots with a razor that where to fused.

After you get the lower jaw removed slide it back into the slot under the chin and glue it into place.

Step 6: Remove Skin: the Body

Removing the skin from the body is a lot of the same.  there is a few more places that they sew the fabric to the plastic.  I followed the seem in most parts. just cutting a little bit of the thread then pulling it apart.

On the underside pull the velcro open.  In the back side where the Velcro ends you will find a zipper leading up to the tail.  There will be stitches at each end holding it together but no slider.  cut the stitches and it will come unzipped.  There will only be a small area holding the zipper area to the Velcro area.  Cut this small bit of fabric and we will move to the front.

The frond end of the Velcro has a small stitch leading to a T intersection.  Unstitch this area then unstitch along both sides of the T till you get to the legs.

Step 7: Removing the Skin: the Legs

There is an inner seem along each leg.  Snip the stitch and tear down each of them till you get to the feet.  The feet are held on with a different fabric that is then looped around a rope inside of the hooves.  Just cut around the bottom of the leg removing this other fabric and freeing the rest of the leg.

At the top of each leg you will need to remove some stitching leading around the intersection of the inner leg and the lower side of the body.  When you get close to the stitches running along the bottom of the pony that you have already cut, snip away the fabric in between.  You should not be able to lift the skin up all the way around the head.

Step 8: Removing the Skin: the Neck

The very last step is to remove the part that is holding the fabric to the neck.  I did this by cutting through the lighter, fur-less fabric at the neck.  After I removed it, I found that it was held on by a zip tie inside of that loop of fabric.  You can do it my way, or you can insert the wire cutters into the fabric at the nap of the neck and simply cut the large zip tie.  This should allow you to remove the skin completely.

Step 9: Removing the Face

To get to the main circuit board in the head, you need to removed the left side of the face (the pony's left, not yours)  There are quite a few screws that you will need to remove to do this. I tried to mark all of the screws in the images below, but if it will not come loose after removing those, just look around for extras I may have missed.  There is also a clip that holds the snout onto the rest of the face.  This clip was difficult to remove and I ended up marring the face a bit with a screwdriver and wire snips.

Under the face you will find that the circuit board is held in place by 4 screws.  Remove these screws, as we will do most of our work from the lower side.

Step 10: Getting Access to the Circuit Board in the Lower Body.

I removed every screw I could find from the pony and still could not get the body open.  I could not see any clips I could open, or anything else I could remove to release it, so I did the next best thing and dremeled a hole in the stomach.  This ended up working out in the end as it provided a good place to put the fuel for the flame thrower.  You will want the hole large enough to allow your PVC tube to just slide in.

Step 11: Cutting the Power to the Microcontroler

To take control of the pony we will cut the power and the ground to the Micro-controller that is currently controlling the pony.  There are two controllers in the pony,  one in the head, and one in the body.  The one in the head sends commands to the one in the body so we will only be cutting power to the head, and this will take care of both.

To do this, cut the trace going to the 4th and 5th pin on the larger of the two boards sticking out at a right angle.  The traces will be on the back side of the board.  The 4th pin should have a white wire soldered to it.  Using a razor you should be able to cut the trace without a problem.

Step 12: Tapping Power for the Arduino

Now we need to power our Arduino, but there is no need to add another battery when we already have the 6 C cells powering the pony itself.  Tapping into the power being pulled into the circuit in the pony's head will give us around 9v.  I had a few 9v wall warts laying around so I cut the cable off of one with 5.5mm/2.1mm barrel jack on it.  I tied this into the connectors going to the head.    You can also purchase an adapter from adafruit ,as that will be much easier.

Step 13: Tapping the Lines Into the Motor Control Circuit.

You will need to tap into the the lines coming out of the motor control circuit coming out of the micro-controllers.  We will do this at 4 spots on each of the Circuit boards.  

On the board in the pony's head you will need to solder your wires into R14 ,R15, R27, and R28

R14 and R15 move the head up and down plus open and close the mouth.
R27 and R28 move the head move left or right as well as move the eyes and ears.

On the board in the body, you will want to solder you wires onto R10,R42 and R11,R41

R10/42 move the head left and right
R11 Moves the tail (only one way)
R41 bobs the head up and down at the neck (moves one way around in a circle like the tail)

Step 14: Taping Into the Encoders.

There are 4 encoders that will tell you the position of the head.  Two of them are located in the head and 2 of them are located in the body.  The two in the head are easy since you can see them when you take the pony's face off.

Solder a ~2' long wire to each of these encoders.  I used 18g wire.

For the encoders in the body, I was unable to find an easy way to get to them, so I cut the end off of the wire.  We will solder the wires from this cable right into the bread board so strip them and you are finished with them for now.  Try to leave these wires as long as you can.

Step 15: Getting the Morors and Sensors Connected to the Arduino.

For the current code you will want to have the pins as such

Resistor label --- Pin on the Arduino

R14    Pin 23
R15    Pin 25
R27    Pin 27
R28    Pin 29
R10    Pin 37
R11    Pin 35
R41    Pin 31
R42    Pin 33

To get the pins connected I soldered them to the end of .1 male header.

Step 16: Connecting a Wii Nunchuck Into the System.

Now you will need to connect the Wii nunchuck breakout board from adafruit.  If you want to run the wii nunchuck at 5v you can just use the .1 pitched pins that are on the breakout board,  you can set the the input pin 19 as 5v output and pin 18 as input.  I connected mine with wires and chose to play it safe by running it at 3.3v.

On your mega, connect it as such
Gnd: Ground
3.3v: 3.3v
Data: 20
Clk: 21

You will want to check the arduino wiring documentation if you are using something other then a mega

Step 17: The Arduino Code.

The code should be loaded on the arduino mega using the arduino IDE.  Before doing so, you will need to put the modified wii nunchuck file into your arduino libraries folder.  It should be in the root of your arduino IDE install. It should look something like "C:\User\joe\arduino-0022\libraries\WiiChuck\WiiChuck.h .  Make sure that you put it inside of a folder named WiiChuck so that it can be found by the Arduino.  After you load this on your Arduino, you should be ready to start moving the pony around.  

The sketch has to bitbang the PWM sent to the motor controls as there are to many pins to do it on PWM pins.  I think it runs too slow for the Arduino to do it with hardware anyways.

Current controls work like this:
Push the joystick one way and the head will start moving that way from a dead stop.
Move it the opposite direction from the way it is currently moving and it will stop moving.
Move it up or down and it will move that way from a dead stop.
Move the opposite direction then the head is moving and it will stop moving.

C moves the Tail
Z shakes the head

The mouth moves when the head is moving up and down.
The ears and eyes move when the head is shaking.

Step 18: Getting the Fuel to the Head

The fuel we are using for the fire is automobile starter fuel.  This can be purchased at most any store that sells automotive supplies. 

To attach the fuel source, we will connect one spray caps from the starter fluid to a teflon tube that runs from the hole in the belly up along the neck and then out just over the nose where we will place our igniter.  The tube will not be the right size to fit into the cap so use a drill bit that is the same diameter as the tube to bore it out until it fits.

Be prepared for some frustration as Teflon is very hard to push into things do to its extremely low Coefficient of friction.  Once you get it in, put some hot glue around the joint to hold them together.

Step 19: Building an Ignition System.

The ignition system is an electric grill ignitor that has had the leads on it extended.  Just over the mouth (or wherever you want the fire to come out) we have attached a metal plate that is connected to one lead of the ignitor.  The Teflon fuel tube is epoxied right over this lead.  Finally, the other lead off of the ignitor is connected to a wire on the other side if the fuel tube, so that the aprk will arc across the tube.

The fuel has nothing to burn so if the ignitor is not running it will blow out in a small breeze.  When modifying the ignitor you will want to connect one 6 foot wire to each lead.  Ours had 4 leads, if you have the same type you can put electrical tape over the other two so that they do not spark inside of the body.  You will also need to insulate the leads that you extended with tape, shrink tube, or hot glue to keep it from sparking at the ignitor rather than at your extension leads.

Step 20: Remote Fuel Trigger

The Remote fuel trigger uses a bowden cable to pull down on a sheet of hinged plexi glass, which pushes the spray nozzle on the fuel can.  A bowden cable is the type of cable that is used in bike brakes. This allows it to be flexible in the middle, but still allows it to transfer force in relation to its end points.

Step 21: Follow Up

I know that I covered a lot and I am sure I missed something.  If something was not clear feel free to ask a question and I will try to clear it up or update the instructable.  I also have a short video from not long after maker fair that explains some of the operation of the pony.

Just remember to keep it safe and have fun.

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