NXT Grunt (2014)


Hello! I present to you Grunt, my entry into the Community’s Action Figure challenge. Grunt is a walking, bipedal, robotic NXT representation of the real Grunt from my original comic series, BLOX!. For more details and a backstory on Grunt, please proceed or watch the video below.

See a video of Grunt here: https://www.youtube.com/watch?v=Gh0VzsxkrNY



As mentioned before, the Grunts are from my series of original comics called BLOX!. The Grunts are a slow-witted, albeit physically strong race of aliens from a distant planet. They have been enslaved by a second alien race, the Artons, who believe themselves to be superior and unaffectionately call these creatures “Grunts.” Under the tyrannical command of the lazy Artons, the Grunts have toiled away, doing all of the hard work and constructing the Arton Empire brick-by-brick. In episode #31 of BLOX, the Artons set their sights on conquering Blox City. However, their plan is repeatedly foiled by the clumsiness of the Grunts. Finally, the Artons reach their boiling point, and so do the Grunts. The Grunts revolt and, as a result, the Artons’ plans of conquest end once and for all and the Arton Empire begins to crumble, as it has become too dependent on the Grunts’ manual labor. So, in the end, the Grunts save the day.

NXT Grunt’s Design


To make the robotic Grunt a great likeness of the comic Grunt, I added a few important design features. First is the head, which features the jaw; it’s big, full of teeth and can be opened by hand; and the blue eyes on each side of the head. The head also houses a Sound sensor.  Next are the arms, which are designed to look muscular and strong and end in a 3-fingered hand. The legs are short and thick. Lastly, the overall shape ties it all together.

Walking Mechanism


The NXT Grunt is a biped; that means he walks on two feet. An NXT motor controls each leg separately. The leg is attached to two 36 tooth gears that give Grunt a circular stepping motion. (Think of pedaling a bike.) This system was partially inspired by DamonMM2000’s FOWL BIP3D. Each leg contains a Touch sensor that is clicked when the foot moves up; this allows the legs to be set to the correct orientation when the program begins. (More on that under “Program.”) Grunt’s gait is akin to shuffling or a waddling penguin… or even an ice skater! It all depends on your perception.



The comic Grunts possess great strength, so it was imperative that NXT Grunt did as well. The arms are powered by a single NXT motor located in the head; it is geared down to the arms 3:1. As mentioned before, the arms are designed to look muscular and strong.


Full Program (new)

NXT Grunt has a very unique program. Much like the program run by K3MOSAB3, Grunt’s program is an artificial intelligence that takes readings from its four sensors (two Touch, Sound, Ultrasonic) and uses that to react with the proper algorithm. At the beginning of the program, Grunt’s legs automatically reset using the two Touch sensors and the Leg_Reset MyBlock. After that, Grunt will continually walk forward. I found that after the legs set to their proper positions, it would only take a few seconds for them to drop in sync, leaving Grunt unable to walk. I countered this with the Forward_Sync MyBlock, that continually adjusts motor power to keep the legs oriented properly. For example, if one motor fell behind in degrees, that motor would speed up, while the other slowed down, until they came close to each other again. If the Sound sensor hears you yell, Grunt will stop and raise his arms (as if to pick something up), then drop them down after one second. It is hilarious to yell “Hands in the air!” because Grunt will do just that. If Grunt sees an object with his Ultrasonic sensor, located under his arm, he will back up and make a 90 degree turn. Lastly, if you prod Grunt’s orange button on the NXT brick, he will roar, then run around angrily waving his arms.

Updates: Sep. 2nd, 2014


1. A track rod has been fitted to the gearing on the arm to allow Grunt’s mouth to open and close when his arms move. Arms up is mouth fully open, arms down is mouth closed.

2. A few flaws regarding the leg syncing MyBlock have been resolved. The revised program is now more streamlined and bug-free.



NXT Grunt is my first (working) biped, and also the first time I had ever created a model of one of my comic book characters. I am very satisfied with Grunt; from the mechanical design, to the programming, to the authentic styling, and lastly, to the walking mechanism that I worked so hard to perfect. Grunt is, in my book, a complete success; I even had a few laughs when designing and playing with him.  I hope you all enjoyed reading about NXT Grunt as much as I enjoyed creating him. Thanks for reading and see you next time!

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