[IDEA] 3/9-speed combinable RC transmission for PF Servo [INSTRUCTIONS!]

[Sariel]

Free instructions & parts list: http://sariel.pl/downloads/

I'm sharing an RC transmission design that I find quite practical. At long last, I was able to eliminate pretty much every problem that bothered me in typical LEGO transmissions.

Pros:

• instant shifting while driving, no need to stop, no jamming, no need to aim and check, 100% precision every time
• gear ratios from 5:1 to 1.6:1
• input and output aligned end-to-end and rotating in the same direction (meaning you can easily swap them and have a transmission that gears up instead of down)
• input and output go through the center of transmission unit, making it easy to integrate into chassis, and the PF Servo can be attached to either side
• the whole unit is heavily reinforced and ready for heavy duty, nothing should yield, at least until selectors disengage from extreme stress
• convenient cuboid shape; can be built with studless or studfull structure
• only 5x7x10 studs big + motors and side beams
• designed to make it easy to combine two units into one 9-speed transmission producing 7 various gear ratios, from 25:1 to 2.77:1

Cons:

• needs a PF Servo
• using a PF remote to operate it involves holding down the lever to keep the transmission in 1st or 3rd gear; I therefore recommend using SBrick and programming convenient buttons, as shown in the video

I'm currently working on a 4/16-speed version operated with a Control+ motor or a stepper. Stay tuned!

Edited April 28, 2020 by Sariel

[suffocation]

Brilliant work! Thanks for sharing

[skaah]

Loved it Sariel! 

[MikeTwo9398]

Found the instructions, I believe 2 days ago, and used it yesterday to motorize my Lego Land Rover 42110.

Already tried several ways to make the Land Rover remote controlled with controlled gearbox but your gearbox is working the best.

I changed one (actualy 2) thing and used another axle as out put.

I replaced the axle next to the output axle with the 16 and 24 gear by a differential. This way I am able to use both ends.

I also added an extra 8 teeth gear on the opposite side of the 8 teeth gear in your gearbox to prevent slipping the 8 teeth gear on the differential.

I am using a buggy motor so I have to gear down a few time to make the car move. At the moment it's driving but has no torque when climbing....

I am thinking of changing another part of you gear box to make one speed very slow with more torque to climb.

 

The other thing I changed is using my broken Servo motor so I can use the normal remote  .

The servo does not return to the middle position when I stop using the remote. 

Just giving a short click on the remote to the other direction it's stops in the middle when going to the opposite direction.