Mini Slot Machine

A Mini Slot Machine, using Lego marble run mechanism to define probabilities of winning.


How it works

This Mini Slot Machine is based on a previous model I have done 10 years before. The ball (the bet) is loaded in the machine on the top red entrance with the main lever, it goes though a probability path using multiple triangle parts to create two OR gates. If the ball falls in the correct path, it triggers the hatch of the ball container and you win, if not, you lose your ball. The interesting mechanism is the resetting one. Composed of levers, connecting rod, gearing and ratchet, it helps to reset the position of the hatch and lock it, thanks to the decoupled motion between the lift lever and the gear/ratchet. Enabling to lift and lock the hatch only when it is open.

You can see how it works in the video below.


Building Instructions

The instructions are 51 pages, step by step high resolution computer (300DPI) generated instructions with partlist, flexible parts, highlighted parts in the same way as official Lego one. 

Regarding the bill of material, they are includes in the instructions and you can watch in the instructions preview below, but you can also checked the exact bill of material on Rebrickable and export in whatever format you want :

Want to know if you can build the Mini Slot machine ? The model has been indexed to rebrickable, check it !

You can buy the instructions with the following button for 5€ excluding tax. You can also buy other building instructions and get an automated discount, you will get 15% off for 2 PDF, and 20% off for 3 PDF on the total). The automated discount is available for all the instructions for sale on

See it on the shop

After your payment, you will be redirected to a page for downloading your instructions, and will receive also the link to download by email. Please check the spam box and be patient to receive it. If you have trouble to download your copy of the PDF after payment or open the document, do not make a paypal dispute, please contact me using the contact form. The link to download the instructions expires within 48h. Contact me if you have lost your instructions. Note that you can print it, but not copy or distribute. Thank you for supporting my work 🙂

Here is some preview of the building instructions :