First Experiments

As part of the design sprints we did at the start of the project, we started experimenting with the surface tension of water. How it interacted with different materials and especially the formation of drops.

This then got us interested in these discret units of water. We found this form fascinating as it stood in contrast to the 'fluidity' that is usually associated with the medium. Here we started building different prototypes that would show this property.

First Prototypes

For our first prototypes we wanted to experiment along two main routes, one where the water is contained within tubes, the other where the water is in the open in the form of drops.

Tubes:

For the system contained within tube we built a setup that mixes burst of water and air into clear tubes that would be pushed along. the surface tension of the water would hold the sections separated.

Printer:

For the system that worked with drops, we built a sort of printer head that had to be moved across a surface. The valves in the printer head would release a small but consistent amount of water according to pre-programmed timings

We liked the look and feel of the drops of the printer setup more than that of the tubes so we decided to continue with that for further development. However we did not like that the printer head needed to be moved of the surface to produce text. Therefore we decided to combine the idea of the scrolling text of the tubes with the drops of the printer, and wanted the drops to roll down a surface so that the printer head could stay in one location.

Material Experiments

To facilitate the drops rolling down away from the printer head we needed a surface with very specific properties:

 - low rolling resistance of the drops

 - regular and predicable paths the drops would take

 - a surface that would retain these principals for an extended period of        time

We tried out alot of different materials from soot over PTFE to textiles. We had the most success with soot, wax and textiles

The soot had the benefit that it was extremely hydrophobic however it was also not very durable and could only be used for a couple of passes of drops:

Wax was also somewhat successful as it was more durable than the soot however it still eroded pretty fast and it was not that easy to make sure there was no unwanted structure in the surface:

That is why we ultimately went with a textil surface as some were still very water repellent and we could find very evenly manufactured samples that would mean it was easier to get the drops to roll down the surface in an even and predictable fashion:

The textiles worked so well due to the surface tension of the drops as they only sit on the tiny fibers of the material and so only have a very small contact area resulting in very low rolling resistance:

Final Material:

Dropper Experiments

We also worked on a new water release system that could more reliably dispense the same sized drops onto the surface. We tried out different nozzel forms:

We found that using the surface tension of water was helpful again to create very uniform drops. This is because there was no other materials that the drops are attached to that may have more unpredictable levels of friction. We then tried to optimise this design:

Once we had found a dropper form that produced consistent drops we then moved on to combining 5 droppers together into one unit:

Technical Setup

To improve the consistency of the amount of water delivered to the droppers and simplify the setup, we moved from valves to peristaltic pumps for the final setup. These came with their own challenges however. We had to add air buffers after the pumps to damped out the inconsistent flow rate.

Final Model