Introduction: 3D Printed Automatic Walking Robot

When I was looking around instructables I came across this walking robot made by crashbot and was fascinated by it. It was so simple yet very functional. I knew from that moment that I had to make one for myself. When a school engineering project came along I knew this was the perfect opportunity to finally make one. I took the idea from crashbot but as you will see my design is quite different. Enjoy!

Step 1: Gathering the Materials and Tools

To make this mini walking robot you will need some tools and material, many of which can be found that are common in the workshop.


  • Philips head screw driver
  • Dremel or hacksaw
  • Hot glue or another form of adhesive
  • 3D printer filament and 3D printer
  • Soldering iron
  • Wire strippers


  • Double gear box( you will only need one)
  • 2 different color wires
  • 2 AA Batteries and battery terminal
  • 4 aligning pins
  • 8 small washers
  • 4 small bolts
  • Switch
  • Heat shrink (optional)
  • 4 lock nuts
  • Small weight

Step 2: Starting the 3D Prints

First you are going to need to 3D print the legs and the main body piece and the 2 crank arm pieces for the legs. The 3D printer that I used was the cube. I also printed all the parts in PLA and all turned out to be fine. If you look to the pictures above you can see the settings that used within the cube software. I had to redesign the legs from what crashbot has because when I first printed the legs the "feet" parts had broken off. I added a long I beam type of support to make the feet more sturdy and have more strength. The prints were fairly quick with the body taking about 2 hours, the legs taking another 2 hours and the crank arms only taking a quick 21 minutes. Once the pieces are all printed you can start assembling the robot.

Step 3: Electronics

The electronics for this little toy are really simple. The switch I used had only 3 terminals so it made wiring it up super simple. The wiring for the switch goes as follows, the center lead needs to be the black or what ever your negative wire color is. This will also run to the negative part of your battery terminal. Then take the positive wire and pick a side where you want your switch to be on. Be careful with this step and choose carefully because what ever side you don't choose will be your off side and the other will be the on position. That wire will go to one of the terminals on the motor that is hooked up to the gear box. Now that we have that all wired up you can take the positive wire that is on your battery terminal and solder that to the other lead on the motor. Now if you take two AA batteries and flip the switch you should have power! Now if you feed the wires through opening for the switch you can use your adhesive to secure the switch to the bod of our robot. The pictures above show how the wiring to the gear box and the switch should all go together.

Step 4: Gear Box

The gear box I used was from a dual pack but I only used one of them. The configuration needs to be the third one on the instructions. The gear ration should be around 114.7:1 because anything lower would make the robot walk too fast and not have the correct motion. The photos above show how the gear box should be assembled. The axle we need has to be 2 and 1/16 inches so some cutting may be in order. If cutting is required then always use safety gear and cut at your own risk. Once the axle and gear box is finished we can move on to the next and most fun portion of this instructable... Assembly!

Step 5: Assembly

Now this part can be a little frustrating especially if you have to work only with what you have around the shop. On the top holes of the base you are going to want to take 1 of the washers and the aligning pin and feed it through and use some adhesive to make sure it does't move. On the outside if you also use some washers on the inside of the leg it gives it some strength and won't want flex when it is walking. Once that is completed then the crank arms can be attached to the axle that we cut down earlier. Some adhesive in the hole proves to be very effective to keep the axle secured. Taking another aligning pin through the hole closest to the park that has the plus in it. Then the pin can be fed through the small hole and the lock nut can be secured on the other side. The crank arm now should be able to spin freely. Once this is done you can repeat it for the other side. However, when the crank arm is attached on the side it needs to be 180 degrees from the other side. Then that same process can be repeated for that side as the other. Then using the small washers as spacers make sure the legs are square with the base of the robot. Adding the final small wight under the switch will balance out the robot so it can walk successfully. After both sides are all put together the top part of the legs get two lock nuts to make sure that nothing falls off and your assembly is complete!

Step 6: Now Your Finished! Flip the Switch and Start Marching!

Now all that's left to do is plug in the batteries and flip the switch and your all set to start your little marching machine!

I hope you found this instructable to be interesting and fun! If you have any questions or comments feel free to post them below in the comments! All feed back is welcome and appreciated! Also if you want to make one of your own I would love to see how it turns out! Feel free to check out my other instructables while your here. Good luck and happy marching!

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