Lego Monorail Motor with Direction Selector Slide Switch

Lego Monorail Motor with the direction selector switch that was included in the original motor

This uses a “MS-23C01” sliding switch on a custom designed pcb, that also allows you to power the motor from a small lipo battery inside the motor. The circuit is copied 1:1 from this and rearranged into a smaller package, allowing you to transfer all components to the new pcb: aliexpress.com/item/1005007109146834.html you can also reuse the battery from there. For use without the charge circuit just solder the power input to the "bat” terminals and only populate the switch on the pcb.

If you don't see yourself ever making a rechargable battery powered version you can use the "selector switch pcb.zip" instead, it is easier to solder, one side is power in the other is power out, the motor is connected to power out.

You can get the pcbs for around 10$ from jlcpcb or from any other service.

Parts required:

1x 12V N20 motor 1200 - 1500 rpm (1200 is a bit slower than original, 1500 is a bit faster)
   link: aliexpress.us/item/1005005240947116.html 
1x 12t 0.5M 3mm d gear
   link: aliexpress.com/item/1005006856152235.html 
2x 25x2mm Steel axle
   link: aliexpress.com/item/32491052502.html 
2x M2xL4xOD3.2 Heat Set Inserts
   link: aliexpress.com/item/1005006071488810.html 
2x M2x6 or 8 Bolt
   link: aliexpress.com/item/1005008691176275.html 
2x M1.6x6 screw
   link: aliexpress.com/item/4000970993800.html 
1x 9v connector pcb
   order with any thickness
1x switch pcb
   order with 1.2mm thickness
1x switch
   link: aliexpress.com/item/1005006313610124.html 

If you want to build it with a battery inside, you also need this (for parts, you will be taking it apart. you can reuse all the electronic components other than the motor and the base pcb and solder them to the new pcb. You can also reuse the m1.6 screws and the switch from there and don't need to order them separately) aliexpress.com/item/1005007109146834.html. The USB socket is part C30167344 on LCSC, the rest of the parts are just standard 0603 smd components. The usb socket needs to be sanded down about 1mm to not stick out from the underside.

For that you need to transfer all the parts from the pcb inside of the motor above to the new pcb.

The square pads on the pcb are positive.

The “selector switch + battery management pcb” con be used with battery or without, “selector switch pcb” can only be used without.

For the battery version you might need to make the switch more loose for the motor to change direction fully by slightly pushing the spring part up a bit.