Voice Changing Robot Costume W/ Animated Mouth

We made this robot costume about 3 years ago for our 7 year old at the time, and posted a photo of it here last year. Since then I've received numerous requests to explain how it was done in a step by step. I still have most of the robot sitting in my office, so I took some more photos, and dug up some schematics so you get a better idea of how you can make your very own!

Step 1: The Anatomy of a Robot

Here's what you need:

For the BODY

• Numerous cardboard boxes of various sizes for head, body, and feet.
• 2 or 3 rolls of aluminum foil tape used in duct installation. Like this.
• Metal dryer duct. (Size dependent on size of arms and legs of wearer)
• Black cotton gloves
• Material for antenna... we used shavings from a pipe threader
• 2 aluminum cans
• Black turtleneck shirt, or a black neck gaiter to hide the wearer's neck.
• Hot glue

For the ELECTRONICS

• 1 - Velleman Voice Changer kit.
• 20 clear lens LEDs (color is your preference, but you'll want a clear lens to make the unlit ones more discreet)
• 1 Small speaker
• Resistors of the following quantities and values:
• 10- 330 ohm (9 for mouth, one for eyes)
• 1 - 470 ohm
• 1 - 1K ohm
• 1 - 2.2K ohm
• 3 - 4.7K ohm
• 3 - 10K ohm
• 3 - 33k ohm
• 2 - 39k ohm
• 2 - 47k ohm
• 1 - 100k trim pot
• 10 NPN Transistors
• 1 PNP Transistor
• 2 - 22uF electrolytic capacitors
• 2 - 4.7uF electrolytic capacitors
• 9 - 1N4148 or similar diodes
• scrap ribbon cable and hook up wire

The most important thing is to be creative, and willing to improvise with the materials you have on hand.

Step 2: Constructing the Body

Building the body is pretty basic. It's essentially just some creative use of cardboard, tape and ducting.

You will want to put the speaker on the body. If the speaker and microphone in the head are too close together, you will get feedback. We chose to just put the speaker on the front of his chest to make it easier for people to hear him. You might be able to find a more discreet location to put it without it being so close you get feedback. A little experimentation may be necessary.

We chose to make the body a little long to cover his behind, so only the duct legs would be seen, however it made it more difficult for him to walk... You may want to go with a shorter torso to ease walking.

Depending on the age of your robot, you may need to use larger duct. For our 7 year old, we used 3 inch for the arms, and 5 inch for the legs. We just had him try on different sizes in the hardware store.

The feet were made from cardboard we folded into some form of shoe shape, and put them over his shoes.

The gloves are just black cotton work gloves covered in foil tape. You will want the wearer to be wearing the gloves while applying the tape for proper fit.

Since the head contains the majority of the electronics, we'll cover its construction on the next step.

Step 3: The Head, Part 1

The actual head itself, like the body is pretty simple. We used a box that held a 12 pack of beer bottles, it seemed to be the perfect size for our young robot.

You will need to find a creative way to keep the box snug on the wearer's head. We had him wear a big fluffy winter hat and stuffed other bits of rags and other fabric around the hat to keep it stable. We ended up having to add vent holes on the sides to allow our robot to hear.

The electronics were placed on the top, and covered with plastic just in case it rained, and to keep young hands off of the electronics.

Step 4: The Electronics

Look at the photos for notes pertaining to building the electronics.

The primary part of the electronics is the Velleman Voice Changer kit. Assemble the Velleman kit per the instructions, except be sure to NOT install the microphone on the PCB. Instead of wiring the mic on the circuit board, extend the mic with a wire long enough to put the microphone near the wearer's mouth.  The output of the voice changer goes to the speaker on the chest. The animated mouth comes from a VU circuit made from the transistors, diodes, and resistors, etc, which is also wired to an output of the voice changer.

The VU circuit (see photos) comes from this page I found on the internet. The designer does a great job of explaining the theory of operation... He even makes a kit. Since we're using a mono source, you only need one channel of the circuit. The circuit has two parts, the 'bar graph' and the 'front end'. The input to the front end is wired to the voice changer circuit, at a point BEFORE the input to the volume knob and LM386 amplifier chip... (There is a schematic in the voice changer instructions) Look at the photos to see where I tapped this signal to the VU.

The power for the eyes and the VU circuit is wired from the power switch of the Vellman kit, to allow everything to be powered from one battery, and turn on and off with a single switch. Look at the photos to see how the power distribution is handled.

The eye LEDs are wired in series, with a single 330 ohm current limiting resistor... You may need a different value, depending on your LED. The LED Center has a great resistor calculator for LEDs here.

Step 5: Trick or Treat!

When you finally get everything assembled, you will find that some adjustment of the volume might be necessary to avoid feedback.

It should be noted that this costume is cumbersome to say the least. Where we lived at the time, most of the houses had steps leading up to the front door, and they proved quite difficult for our young robot to ascend without assistance.

You may also find your young robot is a popular attraction while trick or treating... we were only able to visit a handful of houses, because of all the attention he was getting. :)

I should also mention that this isn't necessarily an inexpensive costume to make... Even though it's mostly tape and cardboard, the price of components can add up quickly if you don't have those items on hand. We probably spent close to $100 making this costume, but we don't regret a single penny spent, for it was one of the best Halloweens ever! :)