Tangible base

This article is about creating a so-called base for a tangible.

For starters, what is a tangible base?
In short, it’s what connects a tangible with a Touchscreen. Therefore it more or less needs to simulate fingers touching a screen. As we (and almost everyone nowadays) is using capacitive touchscreens, this means it works via conductivity and not via force. This, for example, is also the reason why you need special gloves if you want to use your smartphone while wearing them.
So our first condition is that we need some conducting material which simulates a finger, in our case we tried copper band, conductive filament, the tip of a stylus, iron band and in our final version cut parts of sealing material.

Also, it’s important that this material has to be grounded therefore we need at least 3 points which we have to connect (we’re using copper and for that)
In earlier versions, we used 4 points which made it easier to differentiate the tangibles. But as we’re just using one tangible in the end, 3 points were enough. We also tested different sizes of the feet and distances between them, so the touchscreen is recognizing it better.
It took a lot of trial and error to get a satisfying result.

Stylus tips, copper over wood, metal stripes over rubber… Iteration is key.

We also created light wood models in the beginning which resulted in bases which were too light. The base needs a certain weight to better connect with the touchscreen.
In the end, as a reference, we used a model which we got from the Fablab of Aachen. This model was also round and has 3 feet.

We adjusted it so we could cut the model instead of printing it and also edited it for the needs of our tangible. This means we needed some space for electronics, specifically an IMU, a NodeMCU, a self-made PCB, some cables and a hole to reach it with a USB plug.

For more information on how to build your own tangible(base) recommended sources are

https://www.instructables.com/id/Object-Interaction-With-Touchscreens/ & https://dl.acm.org/citation.cfm?doid=2807442.2807466

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