[EV3]The Wheel of Fortune, a physical user interface (PUI)

[Hanso]

For those who have not following my topics, a small introduction about Sioux.NET on Track, a large full automated Lego candy factory, trains, lots of Mindstorms EV3 and all controlled by a Microsoft C# application.

Quote

 

Sioux .NET on Track is one of the expertisegroups of Sioux Embedded Systems in Eindhoven (The Netherlands).

We are a group of enthusiastic software engineers who come together after working hours to get experience with Microsoft.NET. To make learning fun, we develop an application in C# for making a full automated Lego train, using Lego Mindstorms NXT, Lego Mindstorms EV3 and Lego Power functions.

 

Every year, we show our layout at Lego World in Utrecht, the Netherlands. You can watch videos on our Youtube channel (www.youtube.com/user/siouxnetontrack) with the progress of all the updates and changes we make and you can also watch a video of the layout at Lego World.

The video from 2017 and 2016:

 

 

We always have an interface to the visitor, the so called 'PUI' which is an abbreviation for Physical User Interface. The visitor can choose the color of the candy (s)he wants to be delivered. The colors red, green, blue and yellow can be chosen. Okay, okay, its is more purple than blue. But in our layout, that is the blue candy ;-)

 

Through the years, we have had several types of PUI's:

In 2016 and 2017 we used a so called Wheel of Fortune as the color selector:

The visitor had to pull the lever, making the wheel rotate. For an adult, this works fine. But lots of our visitors are little children, who have never seen a wheel of fortune. So some children pushed the lever, some pulled it but now hard enough and some children thought they had to pull the lever and push it down until it would touch the floor. Sometimes, I really thought the Lego would crack but fortunately it survived the hundreds of enthousiastic kids.

 

For Lego World 2018, we've made an update of the Wheel of Fortune. Instead of a lever, we decided to use a motor for the rotation. But I found out that this was easier said than done. The main problem is the weight of the wheel, it needs quite some torque to start rotating. Plus I needed a free-wheel mechanism: when the motor turns, the wheel should turn. But when the motor stops, the wheel should keep rotating until it is stopped by the pointer.

I first used the free-wheel mechanism from the lever:

However, he torque was too much for this free-wheel mechanism. So, I started looking on the internet for a more powerful version. On the Youtube page of William Sargeant, I found a version that looked more firm. I made two of these and in combination with two EV3 L motors it is powerful enough to spin the wheel.

 

Apart from that, I mixed the colors in the wheel. The result:

And of course a video:

 

I need to design two buttons that will be controlled by the visitor. A green button to start rotating the wheel and a red button that stops the wheel. I'll keep you posted.

 

Thanks for reading and watching.

Enjoy,
Hans

Edited December 27, 2017 by Hanso

[Aventador2004]

Fun! I will be watching this topic!

[Hanso]

38 minutes ago, Aventador2004 said:

Fun! I will be watching this topic!

Thanks. Any suggestions for designing the start and stop buttons?

[Aventador2004]

45 minutes ago, Hanso said:

Thanks. Any suggestions for designing the start and stop buttons?

A button, that activates a clutch on or off. As in one motor turns the wheel, and when it needs to stop, the clutch releases, then gets stalled by a stopped gear.

I think that is described well enough.

[Hanso]

On 27/12/2017 at 4:31 PM, Aventador2004 said:

A button, that activates a clutch on or off. As in one motor turns the wheel, and when it needs to stop, the clutch releases, then gets stalled by a stopped gear.

I think that is described well enough.

I am truly sorry, but I don't know what you mean. Hope you can explain a bit further.

Meanwhile, I designed two start/stop buttons myself. Pressing the blue starts spinning of the wheel, the red button stops the motors.

A timer mechanism makes sure that you cannot press the red button too early (well, you can, but it doesn't stop the wheel immediately). And if you don't press the red button at all, the wheel will stop spinning after a pre-specified time-out.

Edited December 28, 2017 by Hanso

[9v system]

why dont you use a driving clutch connected to a sevo motor to engage the wheel?

 

[Aventador2004]

2 hours ago, 9v system said:

why dont you use a driving clutch connected to a sevo motor to engage the wheel?

 

That was what I was suggesting @Hanso.

[Hanso]

You mean the same mechanism as I used in the Candy Trebuchet (click here for the thread)?

 

 

Yes, that could also work for driving the wheel but I wanted to use a free-wheel mechanism since that saves me an extra motor.

 

Edited December 29, 2017 by Hanso

[9v system]

15 minutes ago, Hanso said:

You mean the same mechanism as I used in the Candy Trebuchet (click here for the thread)?

 

 

Yes, that could also work for driving the wheel but I wanted to use a free-wheel mechanism since that saves me an extra motor.

 

yes this is exactly what i was thinking

[Hanso]

Improved version of the motorized Wheel of Fortune. In the previous version, the motor power was transferred through the axle of the wheel. The wheel is rather heavy, so the torque on the axle was also rather high. In this version, the motor power is transferred to the wheel using the yellow gear rack elements (6151167).

Click on the picture below to view the pictures on Flickr:

 

And of course a video:

 

Enjoy watching,
Hans