Gearing Ratio Calculator
Check out the Beta version my Lego Technic Gearing Ratio Calculator Tool:
This tool allows you to upload your Lego Technic project .ldr file and analyse the gearing ratios between any two connected gears or axles. Currently supports most gears, axles, worm gears, some differentials, cv joints and universal joints. See the video tutorial on how to use it. It is a work in progress and I would love to hear your feedback on it. Click here to try it out.
Note: As of 25 Septemeber 2021 the tool supports CV joints, linear speed via the radius of the component and improves on the frame rate for higher numbers of parts in a model).
Technic Elbow Art
This is a tool to create "Lego Technic Elbow Art" - a series of intertwined elbow pieces as a single sequence. Choose your dimensions and search parameters and search for new dense solutions and set a record!
Download your Elbow Art as an .ldr file and build it yourself. Click here to try it out!
Lego Technic Videos
New Flat 12/20 Gear Friction
The Lego Technic set 42140 App-Controlled Transformation Vehicle introduces two new gears - a flat version of the 12 tooth bevel gear and a flat version of the 20 tooth bevel gear. These gears are designed to have less friction.
In this video I measure the difference in gearing efficiency...read more
Lego Technic Pi Day Machine
Here I present a Pi Day special Lego Technic machine that produces a gearing ratio of Pi/8 using a 56mm wheel driving a 13x13 square wheel.
The correctness of the ratio is confirmed by matching it with output of a 2 differential gearing system that produces a ratio of 355/9...read more
Lego Technic 100 Part 4 Speed Gearbox
This video shows how to make a Lego Technic 4 Speed gearbox using 100 parts. The gearbox is a manual gearbox makes gearing ratios of 1/3, 5/9, 1/1 and 5/3.
The gearbox is demonstrated by hand and by using a Lego Technic Large Power functions motor....read more
Lego Technic Powered Up Tutorial 2 - Speed Control
This is my second Lego Technic Powered Up Tutorial that focusses on Lego Technic motor speed control using the Powered Up hub and Powered Up programming interface. The Lego Powered Up App is run on a Samsung Android tablet. I demonstrate how to set and control the power level applied to a motor.<...read more
Lego Technic Table Tennis Robot
A Lego Technic Table Tennis robot is demonstrated. The table tennis robot can launch balls at up to 10 m/s using two lego technic buggy motors driving a pair of 46mm wheels. The ball baskets holds up to 60 balls that can be fired at the player at an adjustable rate of between 1 ball per second to...read more
Lego Technic Elbow Art
This video presents an online program for generating loops out of Lego elbow pieces. Elbow pieces (part #25214) are used in many Lego Technic models as a decorative part to create tube like structures. You can search for loops within different sized spaces and set the number of elbow pieces to be...read more
Measuring Gearbox Efficiency
This video describes a method for measuring the efficiency of a gearbox using the Lego Technic Powered Up hub. Gearbox efficiency is defined as the ratio of the output power to the input power and here I show how to measure each of these values to allow you to calculate the overall efficiency.read more
Lego Technic RC Forklift
Here I present a Lego Technic Remote Control Forklift model. The model uses articulated steering implemented with a Power Functions Servo motor, and is powered by a PF Large motor. The forks are raised and lowered with two PF medium motors driving worm gears which in turn drive via a 24 tooth clu...read more
Lego Technic Powered Up Tutorial 1
This tutorial is for beginner Lego Technic Powered Up programmers. It teaches how to turn motors on and off, read and set their axle angles as well as axle calibration using the Powered Up app on the google store or apple store....read more
Lego Technic 100 Part Mercedes RC Car
Here is a challenge to build a fully functional Remote Controlled Lego Technic car using only 100 parts. This video shows the result....read more
Lego Technic Gearing Ratio Tool Update
This video presents updates to the Technic Brick Power Lego Technic Gearing Ratio Calculator tool specifically on underconstrained differential systems. These are systems in which the differentials are not fully constrained and therefore have 1 or more degrees of freedom within them.
The ...read more
Lego Technic Powered Up 3 Speed Automatic Car
This video presents a new lego technic 3 speed automatic RC car. The gearbox uses the lego technic powered up hub and 3 motors to drive, steer and switch gears. The car's 3 speed automatic gearbox has 3 forward speeds with gear ratios 1:1, 3:5 and 1:5 and has been programmed us...read more
Lego Technic Powered Up 3 Speed Automatic gearbox 2
This video presents a revised version of an earlier Lego Technic Powered Up 3 speed automatic gearbox. The previous gearbox used a differential for torque measurement and used a powered up large motor to convert the differential rotation into a torque measurement.
However as it turns out ...read more
Lego Technic Gearing Ratio Calculator Tool
Here I present my new Lego Technic Gearing Ratio Calculator tool. This tool allows you to upload your Lego Technic .ldr (Lego Draw) file and it will simulate the gearing system and visualize it as well as showing the gearing ratios relative to the input component.
The tool can be accessed...read more
Lego Technic Omni Directional Vehicle v2.0
This is an improved version of the Lego Technic Omni Directional RC Vehicle v1.0 (https://youtu.be/crj3kOiSmHg). Several improvements are made in this model mainly around the mode switching from driving forwards and backwards to rotating on the spot. In the previous model there was a lot of gear ...read more
Powered Up 3 Speed Automatic Gearbox
The lego technic Powered Up motors and functions have been used to create a lego technic 3 speed automatic gearbox. With the lego Powered Up functions you can accurately control motor speed and motor position, as well as being able to measure the angular position of a motor. These new possibiliti...read more
Lego Fantom Wallet Opener
The purpose of this Lego Technic project was to design a demonstration unit for the Fantom Wallet (fantomwallet.com) - a slimline wallet for holding credit cards. The lego technic mechanism opens and closes the Fantom Wallet uses a 4 state cycle based on an earlier design of a 4 state multi-funct...read more
Lego Technic Measuring Gear Backlash
Lego Technic gear backlash, also known as gear slop, gear play or simply gear lash is explained and demonstrated. The idea for this video came from a previous lego Technic design that exhibited problem causing gear backlash. The angle of lego technic gear backlash depends on the air gap and the n...read more
Lego Technic Omni Directional RC Vehicle v1.0
This Lego Technic RC vehicle is modeled on the Roomba vacuum cleaner from iRobot. The Roomba can drive forwards, backwards and rotate on the spot. This RC lego technic model attempts to do the same but with four wheels instead of two, similar to a supermarket trolley. The vehicle can switch betwe...read more
Lego Technic Single Motor Tank V2.0
Here I present my second new and improved version of a lego technic tank that is driven by a single lego power functions motor. In this version the gearing mechanism has been optimized and far fewer gears are used to create the four different track direction combinations, namely both forward, bot...read more
Lego Technic Gear Meshing Angle Tutorial - how to calculate gear angles
This video presents a Lego Technic tutorial for calculating the gear angle for the correct meshing of the lego gears within a lego design program such as bricklink studio. Three lego gear meshing examples are working through - the first one being a straightforward rotation of the second gear in o...read more
Lego Technic Single Motor Tank
Here I present a lego technic tank driven by a single lego power functions motor. The lego RC tank can be controlled remotely using a single remote channel and driven forwards, backwards, and steered left and right. These functions are implemented by using a single large PF motor and exploiting t...read more
Lego Technic Multi Function Gearbox with Build Instructions
This lego technic multi function gearbox implements two separate functions using just a single motor. It implements the two functions by exploiting the direction of rotation of the motor and implementing one function for the forward direction and a function selector in the reverse direction. The ...read more
Lego Technic Binary Expansion of Pi
This Pi Day video demonstrates how to approximate a gearing ratio of Pi by representing Pi as a binary number and using differentials arranged in a chain formation to create the binary representation. Each differential implements 1 binary digit. If the binary digit is zero the differential can be...read more
Lego Technic Dual Function Gearbox
This gearbox solves the problem of needing three lego technic motors to remotely control a car with 3 functions namely driving, steering and gear changing capability. The lego gearbox implements two functions at once by exploiting the direction of rotation of the driving motor and ...read more
Lego Technic Two Degrees of Freedom 2 speed Automatic Gearbox
This lego technic 2 speed automatic gearbox implements it's second gear by using a two degrees of freedom configuration and blocking and unblocking the lower gearing ratio path by using a switch and rotary catch. The rotary catch is driven by a torque detector and once enough load is detected...read more
Lego Technic Servo Driven 3 Speed Automatic Gearbox
A lego technic 3 speed automatic gearbox is presented using a lego technic power function servo motor to drive the gear change mechanism. The servo motor is driven by a lego electric switch which in turn is driven by a torque detector using a differential at the output.
The technic automa...read more
Lego Ferrari 488 GTE Manual 8 Speed Gearbox
This video shows the design and construction of an 8 speed manual gearbox inspired by the Lego Technic Ferrari 488 GTE model that has come out in 2021. The lego technic set is called set #42125 Ferrari 488 GTE "AF Corse #51".
The gearbox gearing ratios closely approximate the ge...read more
Lego Technic RC 3 SPEED CAR - change gears, drive and steer using remote control
An improved version of a lego technic RC 3 speed gearbox is implemented into a remote control lego car. This video shows three main improvements over the previous gearbox design. The first is an improvement is to replace the 90 degree bugatti stepper with a PF servo motor reducing the gearb...read more
Lego Technic RC 3 Speed Manual Gearbox
A Lego Technic 3 speed remote controlled gearbox is presented with the design process explained. The lego RC 3 speed gearbox allows you to change gears up and down using a power functions remote control. The 3 speed gearbox implements the gear changing mechanism using two parallel axles each with...read more
Lego Technic 2 Speed Automatic Gearbox with Booster Motor
A lego technic 2 speed automatic gearbox is presented. The point of difference of this automatic 2 speed gearbox is a secondary booster motor is activated once the torque detector senses a large enough torque on the output of the automatic gearbox.
The second motor is turned on by a pole ...read more
Lego Technic 2 Speed Auto Car Ramp Challenge - Part 2
A lego technic 2 speed automatic gearbox is put to the test by incorporating it into a lego 2 speed automatic car. This lego 2 speed automatic gearbox implements a number of design principles aimed at improving the gearbox performance - namely of placing the torque detector on a separate pa...read more
Lego Technic 2 Speed Auto Gearbox - a new hope - with build instructions
This Lego technic 2 speed automatic gearbox design uses a worm gear for torque detection and gear switching combined. Previous Lego 2 speed automatic gearboxes have used a Lego differential for torque detection to drive an orange rotary catch to switch gears using a switch component.
The ...read more
Lego Technic Applied Gearbox Theory Improved
This Lego Technic video demonstrates an improved design of a Lego technic 2 speed automatic gearbox based on a theoretical approach. Typically a Lego automatic gearbox consists of two stages namely a gear selector and a torque detector. In this video, both of these components are improved upon.read more
Lego Technic Gearbox Theory Applied - how to apply theory to help design 2 speed automatic gearboxes
This video applies lego technic gearbox, torque, and gearing ratio theory to design a prototype lego 2 speed automatic gearbox. First I describe the main components of an automatic gearbox, namely a gearing ratio selector and a torque detector. The ideal gear switch over torque point is described...read more
Lego Technic torque in practice - how to work with torque in automatic gearbox design
n this video I present a ten level Lego Technic torque creation gadget for testing lego power function motors and automatic gear switching mechanisms. The effect of torque on a large lego PF motor is tested against the theoretical power curve to compare the optimal gear switching point in practic...read more
Lego Technic Optimal Gear Switching Ratios
This video presents the relationship between lego technic motor torque and speed and shows there is an peak power for each electric motor.
The peak power is calculated and a formula presented relating the power operating point as a percentage of peak power. From this an operational power ...read more
Lego 2 speed automatic car. Part 1
This video explores the use of the lego technic "smoothly switching 2 speed automatic gearbox" inside of a test car to see how well it works to climb up a ramp.
The gearing ratio of the 2nd gear of the 2 speed automatic gearbox can be set using a manual 4 speed gearbox to choose...read more
Lego 2 Speed Automatic gearbox - worm gear prototype. Includes build instructions.
This video present a lego technic 2 speed automatic gearbox based on using a worm gear for torque detection. The 2 speed transmission gearbox works by using the linear counteraction force on the worm gear to connect a gear to create a second speed.
This 2nd speed is added to the mai...read more
Lego Technic 3 Speed Automatic Gearbox - FAIL!
This video presents a lego technic 3 speed automatic gearbox design that failed to work as expected. This design is based on an earlier design of a 2 speed automatic gearbox with smooth transmission that worked very well. That technic gearbox was extended by adding another speed to the oran...read more
Lego Technic smoothly switching 2 speed automatic gearbox evolution with instructions
This video presents my latest compact and smoothly switching 2 speed automatic gearbox made out of Lego Technic. It is both smoothly switching and compact.
The MOC gearbox automatically switches down in gearing ratio when the load on the output is sufficiently high by using a new te...read more
Lego Technic 8 speed gearbox using just two levers!? Impossible?
Here I present a lego technic 8 speed gearbox that does the seemingly impossible - creating eight speeds using just two levers. Normally two levers are used to create a lego 4 speed lego gearbox - however this design allows for 1 of 8 different speeds to be selected.
Each lever drives a s...read more
Lego Technic smoothly switching 2 speed automatic gearbox - with instructions
This video presents a smoothly switching 2 speed automatic gearbox made out of Lego Technic. The gearbox uses the "differential jam" phenomena to prevent reverse torque transmission during the gear switch over point, when the driving gearing can be momentarily disengaged.
The ge...read more
How to mesh any two Lego gears on a regular grid!
In this video I analyze all of the eight regular lego technic gears and demonstrate how any two of them can be meshed on a lego grid.
A sum of radii chart is used to determine the possible diagonal meshing combinations. These are then combined with "intermediate" or "idler&...read more
Lego Technic 2 Speed Automatic Gearbox - Compact! With build Instructions.
Here I present a design for a compact lego technic 2 speed automatic gearbox. Instead of using a differential to react to torque on the output it uses the force on the gear teeth to push a liftarm to automatically change the gearing ratio to the 2nd speed once the torque threshold has been ...read more
Lego Technic Relative Friction Measurement - who will win?
The relative friction of four different Lego Technic solutions for transferring motion from one axle to a far away axle are compared. The friction load differences are compared using a lego technic differential to measure the speed difference of the load on two lego medium motors.
The fou...read more
Lego Technic Automatic Reversing Gearbox MOC with Instructions
This lego technic gearbox has been designed to automatically reverse if there is a high load on the output. For example you may have a car that drives into a barrier and it will start driving backwards to avoid it. The MOC gearbox works by using a differential to react to the torque on the output...read more
Lego Technic Two Degrees of Freedom Differential Analysis
This video analyses a lego technic differential system with two degrees of freedom. The mathematics is presented to calculate the output to input gearing ratio for this system as a function of an independent variable x.
Graphs are presented for the equations governing the behavior of the ...read more
LEGO Technic MOC: 1023 SPEED CAR
A 1,023 speed gearbox has been built into a Lego Technic remote controlled car chassis. The car can be steered and driven via remote control using two channels. The gears can be manually changed using ten selectors that drive ten differentials. This allows for one of 1023 different speeds to be s...read more
Lego RC car chassis with slow reverse gearing mechanism
This Lego technic MOC car chassis is remote controlled with forward and reverse and remote controlled steering. What is different about this design is that it implements a special gearing mechanism that allows the car to drive forward at a normal speed, and 1/5 the speed in reverse. It uses a spe...read more
Lego Coin Pusher - Watch this cool machine in action. It really works!
This amazing Lego coin pusher machine is based on the classic arcade coin pusher machine also known as a coin cascade machine or coin dozer machine.
This Lego Technic MOC is made of over 1,400 lego technic parts and weighs 1.527kg. It uses a crankshaft driven by a large motor to move the ...read more
Lego Technic 3 Speed Automatic Gearbox
Here a Lego Technic 3 speed automatic gearbox is presented. The gearbox automatically switches between one of 3 gear ratios, namely a ratio of 1, 1/3rd and 1/9th depending on the load on the output. It uses two 2 speed automatic transmissions in series to create the three speed automatic ge...read more
Lego Technic Brick Power Channel Promo Video
Watch the details and explanations of my latest Lego Technic creations. Learn about Lego technic techniques, components and more....read more
Lego Technic 12 Speed Rotary Gearbox with 3 reverse speeds
Here I present my Lego Technic MOC 12 speed gearbox design. The gearbox implements 3 reverse speeds, a stop gear (zero speed), and 8 forward speeds. The forward speeds range from 0.307 to 1.2 and reverse from -0.067 to -0.36. The lego technic gearbox has a single gear lever to drive two rotary se...read more
Lego 4 Speed Rotary Gearbox with build instructions
This strong and versatile four speed sequential lego gearbox uses the new "Change over rotary catch" (from the bugatti chiron, 42083) component to smoothly select from 1 of four speeds using a single lever. The gearbox implements 1st, 2nd, 3rd and reverse speeds. The rotary catch is kep...read more
Lego Technic MOC Countdown Timer
Here I present a 871 part Lego Technic MOC countdown timer mechanism. The mechanism can be set to count down from up to 255 values implemented by a binary counter. Each count takes approximately 2 seconds giving a range of just over 500 seconds or almost 9 minutes. Once the counter has counted do...read more
1000 Speed Lego Technic MOC Gearbox
Here I present a Lego Technic MOC gearbox with 1,000 different speeds. This is not a sequential gearbox, instead the gearing ratios are selected using 10 switching levers each of which adds a power of 2 to the overall output gearing ratio. A down gearing of 1000 to 1024 at the end of the gearbox ...read more
Lego Technic Binary Counting Machine - You have to see this fascinating counting machine
A Lego Technic MOC modular binary counter is presented and used to measure the RPM of a large Lego Technic motor. The counter is constructed of a series of 4 sides reels each representing 2 bits. These are held at neat 90 degree angle multiples by a micro stepper mechanism. The overflow bits are ...read more
Lego Technic MOC Programmable Controller
Here I present a Lego Technic MOC programmable controller to control two independent Lego Technic functions simultaneously. The controller uses two tank tracks with pins on them to select between neutral, forward and reverse to control a small crane. The timing of the switching can be controlled ...read more
Lego Technic MOC Timer Gadget
An unconventional Lego Technic MOC timer gadget is presented. It is based on 4 pins holding back a liftarm that stops the timer. Each pin is motor driven by a different gearing ratio such that the liftarm can only move once all pins align. This only happens when the number of turns of the main ax...read more
Lego Technic MOC 256 Speed Gearbox
Here I present a 256 speed gearbox controlled by 8 switches. This design is based on a 2 differential N to P gear ratio design presented in one of my other videos. The gearbox allows 256 different gearing ratios to be selected including 1:44, 1:34, 1:33, 1:32, 1:28, 1:27, 1:24, 1:2...read more
Lego Technic MOC Trammel of Archimedes - "Do Nothing Machine"
Here I demonstrate a "Do Nothing Machine" also knows as a Trammel of Archimedes built out of Lego Technic. Although it is known as a do nothing machine you can in fact use it to draw an ellipse! In the second half of the video the mathematics are shown to prove the elliptical shape that...read more
Lego Technic MOC Do Nothing Machine - Shark Attack
This video demonstrates a motorized Lego Technic "Do Nothing Machine" also known as a trammel of Archimedes in a funny way....read more
Lego Technic MOC Combination Lock Safe. Keep your Lego SECURE!
Here I present my Lego Technic MOC combination lock safe. It has four 8 letter word reels and can make 4096 combinations, 522 of which are actual English words - including the word "lego"! You can change the combination lock code using adjustable liftable gears hidden und...read more
Lego Technic 1,000,000,000 to one gearing MOC
This Lego Technic MOC has over a billion to 1 gearing ratio. It is designed to resemble an architectural tower structure. I measure the input speed of over 3000 RPM using a digital tachometer and calculate the rate of rotation of the tower top to be about 222 days per rotation....read more
PI Day Lego Technic MOC using two lego differentials
Here I present a PI Day special Lego Technic MOC that produces a gearing ratio of the match constant PI to 6 decimal places. This is using two differentials to produce a gearing ratio of 355 to 113. Celebrate PI day 2020.
More details of how to design two differential Lego Technic gearing...read more
Lego Technic MOC 63 Speed Gearbox, including reverse!
Here I demonstrate a 63 speed selectable gear box using 6 selectors. The gearbox implements all gear ratios from -32:1 to 31:1. Five differentials are used for this design. Interestingly it has trouble when inverting the input and outputs. The build instructions for this lego techn...read more
How to design N:P Lego Technic MOC Gear Ratios using two Lego Differentials
Here I present a tutorial on methods for designing N:P Lego Technic MOC Gear ratios where N and P are prime using two differentials. Several differential topologies are presented and one cross connected topology is mathematically analysed and the relationship equation between the input and output...read more
How to use a Lego Technic Differential for your MOC Part 2: Computer Generated Solutions
In this video I present optimal computer generated solutions for designing 1:N (N=prime) ratios using a single Lego Technic differential. Insights and ideas are shown for implementing the 1:N designs in practice using Lego Technic liftarms with an example 421:1 gear ratio device. All the possible...read more
How to use a Lego Technic differential for creating prime gear ratios for MOCs. Part 1
Here I discuss techniques for creating prime number gear ratios such as 17:1, 19:1, 23:1, and 53:1 using a Lego Technic differential. Learn the mathematical relationship between the gear to create your own MOC desired ratios. Use this lego differential tutorial to design your own lego gear ratios...read more
Exact 7 to 1 and 13 to 1 Lego Technic Gear Ratio MOC Design
Here I show my Lego Technic MOC design that produces an exact 7:1 gear ratio, as well as a 13:1 gear ratio using a planetary style gear design....read more
How to create 7 to 1 Lego Technic Gear ratio without a Z28! Build instructions included.
Here I demonstrate how to approximate a 7 to 1 gear ratio using Lego Technic MOC without using a gear with a multiple of 7 teeth such as the Z28 double bevel released in 2019. Learn about and get inspired by gearing ratios!...read more
How to measure a Lego Technic Crane's Efficiency. The results surprised me!
Here I demonstrate how to measure the efficiency of a Lego Technic MOC crane using basic physics. Efficiency is the ratio of the useful energy output (the potential energy put added to the weight) the to the input energy (power source power). The efficiency curve is interesting and does not look ...read more
How to modify your Lego Technic Battery Box. Save on Batteries! More Power!
Learn how to modify your Lego Technic battery box to connect to a 9v power supply. Save money on batteries and get more power!...read more