Tote in the Wild

A quadruped robot based on the excellent design and guide from Radomir Dopieralski

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I had been looking to build a walking robot for some time. I had looked at various quad and hexapod designs, and finally settled on a quad that I could buy the servo mounts and connectors for on ebay. This was going to require full size servos, big batteries etc.

Then I came across the great post from Radomir Dopieralski about his Tote robot. I read the fantastic guide that he had written, and could see that many of the things I had hoped to achieve with the bigger robot could be done with this design based on 9G servos.

Whereas most people who have created some kind of making/project log of a walking robot have just purchased a kit and programmed, here was a design that included schematics, code and most importantly a description of the math and physics to enable someone building it to understand the principles behind it.

I was convinced (also by the great message about wanting everyone to build a walking robot ;) and inspired to build one myself.

Here I have a video showing my Tote walking forwards, rotating left and right and finally reverse.

I chose to build my version using double sided protoboard (however a PCB file is kindly included in the package distributed by the original author) as can be seen in the photo gallery.

I was paranoid about stripping gears on the cheap plastic geared servos that I had used previously, so I ordered some metal gear 9G servos to complete this build with. My Tote uses an Arduino Pro Mini 3.3v clone, and I have incorporated the IR sensor and remote (had these lying around) as per the build instructions. I have also implemented the battery voltage monitor for peace of mind.

I needed to redo my servo positioning when I first got the robot going. I had used the arduino command myservo.write(90) to perform my centering prior to assembly, and ended up with incorrect geometry after the robot starts up. After looking thought the code, I could see that the myservo.writeMicroseconds method was used to locate the servos once the calculations had been made, so I dissembled the legs, used myservo.writeMicroseconds(1500) to perform the centering and reassembled and all was good.

Using the Arduino Pro Mini, I had to also change the code for the hind left leg in the servos section to the following (this allowed the pins to line up exactly with the traces on the protoboard):

static const unsigned char SERVO_PINS[SERVOS] = {

// ankle, knee, hip

/* For Pro Micro

14, 16, 10, // front left

A0, A1, A2, // hind left


12, 11, 10, // front left

13, A0, A1, // hind left

6, 5, 4, // hind right

7, 8, 9 // front right


I am pleased to say that this robot performed exactly as expected, and if you choose to build one you should be guaranteed a positive outcome if you follow the directions. I am grateful to Radomir Dopieralski for taking the time to create such a project, and hope that others will choose to build one also - I have learnt a great deal about a walking robot from this project.

  • 12 × Towerpro MG90S Metal Gear RC Micro Servo
  • 1 × 3.3V 8MHz ATmega328P-AU Pro Mini Arduino
  • 1 × 50*70mm FR-4 Double-Side Prototype PCB
  • 1 × Turnigy nano-tech 300mah 1S 45~90C Lipo Pack
  • 1 × Push button switch

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  • Next Steps

    Over.Unity08/29/2015 at 12:43 0 comments

    Next, I plan to add a HC-06 bluetooth module I have lying around, and use a SR-04 Ultrasonics module to create a basic autonomus 'roaming' mode.

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