Want to scare some kids on Halloween? Well, you just found the best way to do it!
In this Instructable I'm going to show you how to build a remote controlled fire breathing skull. It's fully remote controlled and can be operated from a far distance if needed. Apart from breathing fire it also has a pivoting jaw for boosted effect! Right before ignition the eyes lights up and did I mention it breathes FIRE? Let's go!
Step 1: What You Will Need
- I have access to my own 3D printer so obviously I decided to make my own, you can find it here: http://www.thingiverse.com/thing:441087. However, a store-bought skull works just as good.
- An ignition system (https://www.instructables.com/id/Remote-Control-Ign...)
- Flamethrower (https://www.instructables.com/id/DIY-Remote-Control...
- LED diode (http://www.ebay.com/itm/100pcs-lot-1-4W-Watt-Metal...)
- Resistor 360 Ohm 1/4W (http://www.ebay.com/itm/100pcs-lot-1-4W-Watt-Metal...)
- 9g servo (http://www.ebay.com/itm/1PCS-9G-SG90-Mini-Micro-Se...)
- RC car
Step 2: Pivot Mechanism #1
A moving jaw makes it look more alive, but is probably the most difficult part of the entire build. If you are on a tight time schedule, skip this step.
The first step is to remove the jaw by using a knife, dremel cutter, etc. Once removed you are going to drill holes smaller than the steel wire you intend to use. For example, if you use 1mm steel wire, drill 0,8mm holes to ensure friction fit.
Take a piece of steel wire and glue it in place. Do this on both sides of the jaw, and all of a sudden you made a moveable jaw!
Step 3: Pivot Mechanism #2
Glue the servo on a convenient location on the RC car. Use a steel rod, preferably flexible, and make a Z-bend in one end of the rod. Hook it to the servo horn and prepare the skull by drilling a hole on one side of the jaw. Make a loop on the other end of the rod and screw it in place using a bolt and nut. See pictures for visual explanation.
Once done it will work by a switch on our transmitter. By activating the switch the servo should pull the jaw down when an input to dispense the fuel has been made. In case you don't have a transmitter "smart" enough to program, simply connect the servo to a port called "Gear", and by activating the switch it will move the servo to maximum and minimum only.
Step 4: LED Diode Eyes
This part is not too difficult, but makes a huge difference! I highly recommend doing this step as people seems to be very impressed by lights turning on, and I agree, it does add a lot of effect!
What you have to do is decrease the voltage going from the battery to the LED diode. The LED's require a voltage of only 2V, while the battery we use for this project is 7.4V. If we were to connect it directly the light would instantly burn. By using a 360 Ohm 1/4W resistor we will decrease the voltage to a voltage the LED diode can handle.
Use a smaller drill bit than the diameter of the diode and push the wires through the head til the LED fits snuggly in the centre of the eye. Solder the wires from the LED diodes and the ignition wire (heating element) to the electric speed controller output wires.
When pushing the throttle down the eyes will light up, and the ignition wire (heating element) will rapidly increase in temperature. Also, notice how the LED's and heating element are off when in neutral position.
Step 5: Installation
Use a moderate amount of hot glue when attaching the JST connector (heating element) to the skull's mouth. Make sure the kanthal wire (igniter) is positioned in the centre, this will make sure the fire is as far away as possible from the skull.
A quick tip is to pour a decent amount of hot glue in the eyes, wait for 30 seconds and then use your thumb to create a "frosted" appearance of the LED diodes.
Use a bracket, or even glue the skull in place. Angle the head upwards to make it look like the skull is actually watching you. Last step is to glue the fuel dispense tube. The tube should be angled slightly downwards to avoid the skull catching fire.
Step 6: First Test
Even though the fire was right next to the PLA material (skull), it didn't melt but did receive burn injury. I think it's a really cool idea with a remote controlled flamethrower, and the fact that a 3D printed skull shoots it out of its mouth is awesome!
The jaw mechanism worked flawlessly, the servo is strong enough but do not use a servo under 9g, it will eventually break! Even the LED diodes worked perfectly, and I'm very happy that this project ended up being such a success, because it really does look awesome!
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