The Lego RotoSeq


This is a Lego reproduction of the RotoSeq synth that I designed. Blocks are placed at the end of each arm, as the block passes the colour sensor the sound that corresponds with that colour is played.


The Spin


How to play


The RotoSeq is played by placing the coloured Lego blocks onto the end of the rotating platform, each colour represents one of 5 sounds and each position represents one of 12 slots in the sequence.




Robot Lego

The Lego RotoSeq uses the EV3 Lego brick as a processor which controls the motor that spins the disc and receives the data from the colour sensor. The sounds are played from on board wave files.


The RotoSeq build

The RotoSeq is a really simple build, it uses the EV3 brick as the brains, a base and motor to rotate the platform and the colour sensor to detect the position and colour of the 2x2 brick towers.


[a] Lego EV3 brick

[b] Lego Medium servo motor

[c] Lego Ev3 colour sensor

[d] Lego to build the base and platform

[e] Lego 2x2 bricks in Blue, white, green, red, and yellow for the brick towers

[f] A computer with the Ev3 programming software(free download from Lego)

Make it:

  1. Start by building the base around the Lego motor, it doesn't matter how you do this but it has to be sturdy as the platform rotates fast and can be heavy. I geared down the output with an 8 tooth gear on the motor and a 40 tooth gear on the platform side. The base needs to have a boom on one side that supports the colour sensor.

  2. The platform of the RotoSeq has 12 arms but it doesn't matter how you divide it up, I used two wheels from a Lego NXT set which have 6 arms each, I put one on the top and one on the bottom and offset them to get 12 positions.

  3. Now fit the colour sensor in a position that has it detecting a 3 brick high tower in the middle.

  4. Build several 3 high 2x2 bocks in blue, red, white, green and yellow. Fit a 2 unit long axel to the bottom of each one to allow it to sit in position on the platform.

  5. Now program your EV3 brick with the Lego_Rotoseq(download below) program using the Mindstorms EV3 software.

  6. Now run the program on the brick, the up/down buttons controls the speed of the platform and the middle button stops the platform to allow you to add and remove the coloured brick towers.

Credit goes to Edgar McNamara and Rhianna McNamara for all your help on this build, thank you.

Have fun with this Lego project and please email me at if you need any help or have any questions.