Lose your marbles pt 2

This week was a pretty nice change from all the (mostly) individual weeks. The majority of the group was pretty excited about doing something ‘useful’ with marbles so the marble calender was born. Neil later baptised our solution as a really hard way to do something very simple.

Instead of assigning everyone to everything we created part owners – I was chief marble dispenser. The marble dispenser is the part that has the task of bringing the marbles from the stairs to the time slots of the calendar. In group documentation you can see this part dissapeared, I will explain this later.

The dispenser consists of different parts – rais, a cart and a funnel. The rails cover the entire width of the installation. The cart rides on top of it to collect and dispense marbles through the funnel. The cart is driven using a stepper motor and belt that are inside the cart.

The initial design for all parts were made in fusion.

The test rails was milled from wood on the Shopbot.

For the cart we used from an old 3D printer – belts, gears, stepper, bearings, nuts and bolts. For the proof of concept Micky and I taped everything together to get a grasp of the mechanism. We made a quick funnel to see if it would work.


  • Cable management to the cart – since the stepper is moving on the rails inside the cart the wiring is a bit challenging, ideally it comes from the top to reduce extra stress on the rails. Also there needs to be enough cable length to get the desired range. Long cables are not ideal.
  • Dispensing marbles one by one – to put the marbles from the stairs into the time slots it would be ideal if it can do this one by one. To do this we came up with a solution to mechanically solve this. Unfortunatly with a bit of miscommunication and changing ideas this was no longer possible. So we went on to a potential plan B, use a servo.
  • Time vs value – In the end we decided that the added value of the track was next to none. In the final solution you can see we figured out the marbles can easily be put into the time slots with a little bit of gravity. Keeping things a bit simpler we decided to skip the track and I helped out the others where I could.

Lose your marbles week 17

This week I decided to focus on being a bit of an allround help. The biggest highlight was assisting Rutger with his stairs and making the video for the global review.

To start the week I assisted Rutger with the stairs. Everything was thought of and should in theory work. I used a test script for the stepper and together with the others we gave the stairs their first test ride. Since the stairs were not fixed to the enclosure yet things were not stable nor reliable. Also the rotating arm that drives the moving part of the stairs was slipping on the stepper axis. So after this we worked together on clamping down the stairs as much as possible to minimize the instabillity.

To improve the lineair movement we changed the rotating arm for a stepper with a threaded rod. This has two advantages, first it’s lineair moving instead of the circular solution and secondly it’s more stable. Doing some more tests this improved the stairs quite a bit – marbles were able to climb part of the stairs. The two guided rails on the side had some movement and would sometimes catch a bit. This caused the stairs to go up and down a bit skewed.

To improve the skewing caused by the guide rails I looked for some alternative rails with better fitted guides. Once these were attatched to the stairs we were at a pretty high succes rate for the traveling marbles.

In the mean time Rutger was working on the marbles rolling from the moving part of the stairs to the fixed side. After he tried a few new designs we settles on the best one and made some ‘slopes’ with a wood file.

I was becomming a bit obsessed with the final looks of the machine and decided to paint the stairs bright orange. After preparing the stairs for the painting I changed the colour to blue and sprayed the whole thing blue. I think it looked way better but the team thought this was a bit of an unnecesary step :). After this I was no longer allowed to touch the stairs.

To control the machine I made a interface for the front of the enclosure where the user can select what calander they would like to watch. I chose these really nice arcade style buttons, they are pretty big, add a touch of colour and make a good sound. To indicate what machine is selected I added some PTH LEDs from the back. To be honest the LEDs are not attatched in a very permanent way (with tape). But the buttons come with a nut from the back to attatch them.

To wire everything together I connected all the grounds and made wires from each button to the central electronics. Same for the LED’s (with 1k resistor inbetween). I kept all wires pretty long since I didn’t know where the electronics would go. Also to be nice to Joey who connected everything I used consistant colouring for the wires. I skrewed the plate to the structure, not pretty but very functional.

On the last evening I collected all the video and photos from the whole process and turned it into a video. I have some experience with video editing and know how time consuming this can be. Since it was already pretty late I decided to go the easy route and use simple software, Imovie. This is free software for all mac users so I guessed that it was pretty simple (and fast) to use. Upon opening the software I got a pop up asking me if I wanted to make a movie or a trailer. Trailer seemed to fit the bill. Apparently there are a lot of ‘premade’ templates in this software to create fancy looking trailers. I chose one that had the right length and fit with the theme of the marble calendar, Retro.

To make the trailer it’s pretty straightforward you can drag and drop video’s and or photos and change the text in the story board. Next I exported it directly into a mp4 in the right size. All together this took about an hour or so and the results were pretty good, so I can definaltly recommend this process!

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