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Mechanical systems

Mechanical T-Rex

SKU E2K-STM-RBD

Build a wooden Tyrannosaurus that walks. A gearmotor turns two crank plates fitted opposite one another, and that half-turn of difference is what makes the legs alternate instead of moving together. Press red or green on the handheld controller and it steps back and forth.

Grades 6-8 Intermediate 120 min build

/kit

Two crank plates, set opposite, are what make it walk

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Grades 6–8 · fits a single class period
Broken or missing part? We'll post a replacement

Specifications

One dinosaur, down to the last screw

Finished size, materials and part counts for the build.

Finished size 285 × 120 × 160 mm

Weight 202 g

Materials Wood, plastic and metal components

Pieces 16 pieces

Country of origin China

Safety & compliance

Do not put small parts in your mouth and patiently guide children to install them.

Certified with CPC. Full printed warnings are supplied in the manual.

What they'll learn

Four ideas, one dinosaur

All of it sits in the linkage between the motor shaft and the legs.

Mechanical systems

Two plates on one shaft, set opposite, alternate the legs.

Controlled variables

Turn one crank plate to match the other, then test again.

Mechanical transmission

The motor's built-in gearbox trades speed for pulling force.

Fault isolation

Leave a millimeter between the limb plates or nothing moves.

The Mechanical T-Rex kit as supplied, with every plywood piece, the gearmotor, the controller and the screws laid out

What's in the box

Head, tail, two legs and a gearmotor

~40 laser-cut plywood pieces, numbered ① to ⑰
1× TT gearmotor, with the gearbox built in
2× shaft clamping plates, the cranks that set the gait
1× handheld controller, wired to the dinosaur
2× control buttons, one red and one green
1× battery compartment, in the back of the controller
16× screws, 7 mm coarse, one size throughout the build
1× illustrated English manual, 16 steps

You'll need to supply: 2 × AA batteries, fitted in the back of the controller, and a small screwdriver. Step 2 also calls for a lighter, used to soften the insulation on the controller wire so the core can be bared by hand. No wire stripper is supplied. We treat that step as adult-only, and we are reviewing it with the manufacturer. No glue is needed at any point in the build.

How this build works

See mechanics in motion

Build the model, set it loose, and understand the science by watching it work.

Build

Around forty plywood pieces and one screw size across sixteen steps. Step 2 needs an adult to bare the controller wire before anything else goes together.

Play

Fit two AA cells in the back of the controller, press red or green, and it steps back and forth across the table.

Experiment

Turn one crank plate to face the same way as the other and it stops walking. The manual says so in Step 11, and its troubleshooting page says so again.

Where to start

Master the basics first

Work your way up. Each completed kit unlocks the know-how for your next challenge.

Start here

Doodle Robot

Grades 3–5

7 steps

Then this

Mechanical T-Rex

Grades 3–5

16 steps

Finish here

Balancing Robot

Grades 3–5

29 steps

Curriculum alignment

Educator & Procurement Resources

Essential information for classroom integration and school purchasing.

Every kit starts as a box of parts and turns into something kids can actually use. Making that happen means following directions and fixing mistakes along the way. They're tackling real engineering challenges, but to them, it just feels like play.

Product safety

Children's Product Certificate (CPC)

Certified to US children's product safety requirements

Before the second crank plate goes on, ask: what would happen if both plates faced the same way? Build it as the manual shows, with the two plates facing opposite directions, press a button and watch the legs take turns. Then turn one plate to match the other and test again. Put it back the right way and explain what changed. What it shows: the dinosaur walks because two cranks on one shaft move its legs at opposite times; set them the same way and it cannot walk.

Whether you're exploring circuits in a science lab, tackling gears in a makerspace, or learning at home on the living room table, these kits fit right in. One quick tip if you're building a whole class set: build one kit yourself first, so you know where students are likely to need a hand.

PC University Distributors, Inc. is the exclusive distribution partner for E2K Robotics STEM kits to schools and educational institutions. From a single classroom to a district-wide rollout, message the team on WhatsApp at 516-596-1500 or email sales@pcuniversity.com, and they will send educational pricing and the full product list.

What educators & parents say

Reviews

Nothing here yet — and we'd rather say so

Verified reviews will appear on this page as soon as the first Mechanical T-Rex kits are built at home and in classrooms. We don't carry ratings over from other kits in the range, and we don't publish anything that isn't from a verified buyer.

If you've built this one with your class, we'd like to hear how it went — what worked, what didn't, and what you'd change.

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Questions, answered

Before you build

No. The controller is wired. There is no radio in this kit, no transmitter and no receiver, and you can see the cable in every photograph on this page. The black handheld unit connects to the dinosaur by that cable and holds the batteries, so the dinosaur walks within the length of the lead. If you want a kit you can drive from across the room, the Racing Car and the Balancing Robot both use a radio link instead.

The gearmotor spins a single shaft, and a crank plate is clamped to each end of it. Because the two plates are fitted facing opposite ways, one leg is always being pushed forward while the other is being pulled back, which is what produces a stride rather than a hop. Step 11 of the manual is emphatic about this, and the troubleshooting page confirms it from the other direction: if both plates face the same way, the dinosaur will not move at all. The manual describes the finished model as moving back and forth. We haven't yet confirmed whether the two buttons give you forward and reverse or something simpler, so we're not claiming it either way until we have.

The assembly itself is sixteen steps and uses a single screw size throughout, which makes it more approachable than the step count suggests. The complication is Step 2. Before anything is screwed together, the insulation has to be softened with a lighter and peeled off the controller wire by hand, and the kit contains no wire stripper. We treat that as a job for an adult, not a child, and we're reviewing it with the manufacturer. Plan for someone to do that step before the build starts, and the rest is well within reach of grades 3 to 5.

285 × 120 × 160 mm, which is a little over 11 inches nose to tail. Most of that length is tail. It's a flat plywood cutout rather than a sculpted model, so it reads as a dinosaur in silhouette, and the mechanism is deliberately left on show through the middle of the body.

2 × AA batteries, which go into the back of the controller rather than into the dinosaur, and a small screwdriver for the sixteen steps of screws. You'll also need a lighter for Step 2, and an adult to use it. No glue is needed at any point in the build.

PC University Distributors, Inc. is the exclusive distribution partner for E2K Robotics STEM kits to schools and educational institutions. Message the team on WhatsApp at 516-596-1500 or email sales@pcuniversity.com for educational pricing, classroom quantities and the full product list.

16-step manual

In English, with a troubleshooting page at the back

Wired controller

Red and green buttons on a cable, with no radio

Schools welcome

Educational pricing through PC University

Before you start

Step 2 needs a lighter, and an adult to use it