Cardboard Robot With Soldered Circuit

Introduction: Cardboard Robot With Soldered Circuit

About: The Maker Studio is a museum makerspace at Science City in Kansas City, MO. To see more of our creations follow us on Instagram @The_Maker_Studio or @ScienceCityKC

Make your own little light up friend with this cardboard robot & simple circuit tutorial. If you're a little apprehensive about making things three dimensional, just want a little guidance or some tips on working in 3d with cardboard this Instructable is made for you. You'll also learn how to make a simple soldered circuit for your robot. *You'll need to know the basics of soldering to do this Instrcutable.

A bit about circuits:

You are making an electrical circuit. Electricity is the flow of electrons & an electric circuit is a circular pathway electrons can flow through. If the circuit is open, there is a break in it, the electricity cannot flow through. The circuit has to be closed, a complete circle. (see Photo 5)

Your circuit has a switch. A switch is something that makes or breaks connection in an electric circuit. When the switch is off, it makes a break in the circuit and the electrons are not able to flow around. When the switch is turned on, it closes the gap and the electricity is able to move and make the device work. Electricity only flows through conductive materials like metal. Electricity will not flow through some materials, these are insulators. Tape is an insulator. It will be important to pay attention to these things while you build the circuit.

Your LED, or Light Emitting Diode, has two legs- a short one and a long one. The long one is the positive (+) leg & the short one is the negative (-) leg. These are important because the electricity only flows through the LED in one direction; from the positive (+) side of the battery through the positive (+) leg, through the LED's head & back down the negative (-) side. (see Photo 6)

Test your LED & battery by directly attaching them (Photo 7). The LED's legs will go on either side of the batter, like a battery sandwich with the LED legs as bread. Make sure the positive (+) and negative (-) sides are matched up.


Main materials:

These materials are for making the body of your robot.

  • Cardboard
  • Scissors or Shears- scissors will work but shears make cutting cardboard much easier
  • Pencil
  • Hot glue/tape- to attach the cardboard pieces together
  • Optional- Canary Cutter for cutting down boxes

Detail materials:

These materials are for adding features and details to your robot it's up to you what you use but here are some examples.

  • Adhesive (if you want to use something other than your hot glue/tape)
  • Beads, gems, buttons, googley eyes, paper clips, decorative tape, markers, +++

Circuit materials:

  • 2 LEDs
  • Coin cell battery
  • Battery holder
  • Switch (ours is a SPDT slide switch found here:
  • Wire- 2 colors
  • Electrical Tape
  • Wire stripper
  • Helping Hands
  • Soldering Iron & Solder

Step 1: ​Cut Out the Head & Torso

If your cardboard has a good side & bad side, use the bad side to trace out your head and torso shapes & cut them out. Don't worry about arms, legs, etc. we'll make those later on. For the photographs above our good side is the pink side with writing.

Flip your cardboard over and trace out the shapes onto another piece & cut them out. This will give you two mirror image heads & torsos like in photo 3.

It's a good idea to keep your cardboard scraps handy so that you can pick out little pieces you may need later on. You can keep them in a container lid or plate so that when you're all done it's easier to dump the unused scraps into the recycling bin.

Step 2: ​Make the Sides

Since we're making a 3D robot the head and torso are like little boxes. They need a left side, right side, top and bottom. You can cut those out as thinner or thicker sections based on what you want your robot to look like.

Make the first side piece:

Take your robot's face and lay it next to a piece of scrap cardboard, lining it up with the bottom, and make a mark showing how tall your right side needs to be. It needs to match the height of your robot's face. Now you can draw out the rest of the right side based on how thick you want it to be. (Photo 1)

Make the other side pieces:

Make the left side the same way- by laying the face next to a scrap piece of cardboard & making a mark to the right height. You can use your right side to help measure the width- in the photo (#2) it is the piece that's below the cardboard scrap. (Photo 2) Once you have both side pieces you can lay them out like in Photo 3.

Make and add your top and bottom pieces, then you have all the parts for your robot's head. (Photo 4)

Make the robot's body pieces the same way you made the head. After you are done you can set the pieces aside, we'll work on them more later after the circuit is built.

Step 3: Cut & Strip Your Wires

You'll need 2 longer wires of 1 color (blue in photo)- make these 2x the height of your robot's body.

You'll need 3 shorter wires of 1 color (yellow in photo)- make these 1x the height of your robot's body.

Strip all wires with enough metal cut that you can easily solder it.

Step 4: Adding Wires to LEDs

Just a reminder that the LEDs have specific legs for their positive vs. negative sides. It's important to keep these straight so that you don't hook your circuit up backwards. Solder the long wires to the positive side & the short wires to the negative side.

Step 5: Solder the Negative Side of the Circuit

  1. Solder the last short wire to the negative side of your battery holder. (Photos 1&2)
  2. Solder the other end of the wire to the middle pin on the switch. (Photos 3&4)
  3. Twist the two negative wires on the LEDs together & solder them on the end pin- the one by the #3 on the switch. If you have a different switch than ours you can hook up your circuit with alligator clips to test it and see which pin you need to solder to. If your switch is tiny, like ours, be careful to only add a small bit of solder. Too much solder can easily make a bridge between the switch's pins and make it not work right.

Step 6: Connect the Positive Side

Hold the positive wires onto the positive side of the battery holder & test your circuit. Make sure you're making good contact with the un-soldered parts. If you find an issue take the time to re-trace your path through the negative side of the circuit;

  • Check your solders to make sure they're strong and you light doesn't flicker as you move the wires.
  • Check that you have soldered the right parts together (negative side of the battery holder & LEDs, etc.).
  • Check that your battery is in the holder properly.

If all is well, Solder the positive wires to the battery holder.

Hello world! You've soldered a simple circuit!

Step 7: Insulate Your Wires

The wires will be smooshed together into a tiny robot container so you need to make sure they don't short circuit (touch each other and cause the circuit to malfunction and overheat). Cover any exposed metal wire with electrical tape.

Step 8: Add Your LEDs to the Robot's Face

  1. Bend the LEDs carefully so that they are at a 90 degree angle from the wires. (Photo 1)
  2. Poke 2 holes for the LEDs in the cardboard with a pencil or push pin & insert the LEDs.
  3. Flip the robot's face over & hot glue the LEDs in place.

Step 9: Assemble the Head

Now that you have your pieces made and laid out you can start to assemble your robot's head into a box. Hot glue is preferred (& shown in the images), but you can also use tape to put the pieces together. Put a bead of hot glue along one edge of the face, then take the corresponding side/top/bottom piece and set it onto the hot glue at a 90 degree angle (meaning it is making an upper case "L"). Be sure to hold it in place until the glue is cooled and it stays on it's own.

Add the second side/top/bottom piece & let it cool until secure. Now you need to reinforce it with glue in the corner. (If you're using tape, add a piece of tape that goes around the outside of the corner to hold the two pieces together).

Keep repeating this process until you have 3 sides attached & their corners reinforced. (Leave the bottom open for now.) Add on the other face piece by putting a bead of hot glue along the top edge and then pressing down until it's cooled. You now have a three dimensional robot head!

Gather the wires coming out of the disembodied robot head & wrap some tape around them to make them more managable.

Step 10: Assemble the Robot's Body

You'll work in the same manner as with the head to assemble the body.

Hold the switch in place and trace around it to see how large your hold needs to be. Cut the hole out, place the switch in & glue it into place.

Flip the robot over & you can attach the rest of the circuit with tape or glue. You'll have to coil the wires a bit, be careful to to break any of the solders.

Add on the 3 walls, leaving the top open this time.

Add on the back as well.

Step 11: Add the Last Sides

Add on pieces to the top of the torso and bottom of the head now. You can hold them up to measure & mark, then cut to fit and glue in place.

Step 12: Add Arms, Legs & Details

If you've got some larger pieces of cut cardboard you've been saving this is a great time to use them. Cut test arms and legs and lay them out to make sure you like them, adjust as needed. To give them a little more dimensional you can layer multiple pieces of cardboard on top of each other- add some felt for a pop of color.

If you want your arms or legs to come out at an angle you can cut the ends (Photos 3 & 4). Be careful, if your legs are at too much of an angle your robot may not stand up well. Arms and legs take a bit of time to set in the right position as the glue cools, you may need to hold them in place for a minute.

Now that you have the main parts of the robot done you can dress them up with your craft supplies & recycled materials.

Your robot may be able to stand on its own or you may need to glue its feet to a surface to hold it up.

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