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Color-matching table and our spot at the exhibition, this is how it looked yesterday!

There were lots of people coming over curious about how it worked. And it like we put a lot of smiles on peoples faces when the cups vibrated.

It was very fun to see that most of the people trying out the cups that got matches ended up toasting with the cups after each match.. what have we really developed!? 😛

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Images of the final Design

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More to come…

Final Resource List

This is a rough list of resources needed to build one cup:

  • 1 Thermos mug with detachable inner and outer parts (you can get one at Åhléns)
  • 1 Arduino Nano
  • 5 RGB LEDs
  • 1 nRF radio transmitter (?)
  • 4 transistors
  • board with15x11 pin holes (you might want to make it slightly larger so that you get a nicer board than we did…)
  • 15 680ohm resistors
  • 4 1Mohm resistors
  • 1 small switch
  • 1 9V battery socket
  • 2×15 female pinholes
  • isolated wire
  • Strips of copper or equivalent
  • Paper cup to fit into the thermos mug.
  • …and wire, solder, tools and some other bits and pieces.

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Debugging the Sensors

The sensors have takes a lot of time for this project… We’ve experimented a lot and learned a few things along the way. The biggest issue is that we have no real ground as reference, since the cups are carried around. We’re actually using the “wrong” method for measuring capacitance, but we’ve managed to get it to work anyway 🙂

Our first problem was the the signal cables from our sensors were interfering with each other, which messed up the readings. Touching one sensor would affect all the others. We solved this by using wires with isloation, and connected the isolation to ground. In the final circuit only we managed to only have a few millimeters of wire/solder between the sensor cable and the arduino pin.

We had no way of solving the ground problem. Instead we found a work-around. By restarting the program within relatively short intervals (0.5-2 minutes) we could reset the ground reference value. I do now have the knowledge to understand exactly why this workes, but it does. We improved the readings by putting grounded strips of copper behind our copper sensors. We have some idea of why this works, but not a full understanding of it… Mostly we’ve just been trying stuff, either by reading what others have done, or just experimenting.

Lastly we moved the sensors closer to the surface to get better readings.

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Circuits

(Old post that was never posted)

We’ve now begun soldering our circuits onto real circuit boards. Unfortunately the first two boards were not as good as we would like – the size is OK, but the cables connected to the sensors are very sensitive to interference, so we get a lot of disturbances in the measurements. On a second iteration the sensor cables are carefully isolated up to only a few millimeters of the receiving pin, and this board seems to work even better than expected!

The design of the cup has changed dramatically from the original idea. Since we failed to find a good material for making a glowing cup we’re going for a nicely decorated cups instead. A striped pattern indicated where the vertical sensors are placed.

We reduced the number of sensors from six to four because of the interference. However, this might have been unnecessary with the success of the latest circuit. The sensors seem to be able to distinguish touch from no touch, but also an idea of how large part of the sensor that is covered! Exactly how precise these measurements are is yet to be seen.

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Yesterday (Friday) was a big day, we had planned to have a working prototype this day. So that we could start testing them in real life situations as we had planned in our schedule. if you read the last post from Wednesday, you might know we had big plans on building awesomeness with the finished thermo cups that had dual layers.

In the morning we first needed to find out how conductive our filling materials where. So shampoo didn’t work, as this test turned out positive. We did actually not test the conditioner that we also had bought just because in our minds that has probably the same characteristics. Actually this is false, conditioner doesn’t conduct electricity, which we later tested almost when we where headed home for the day.

Anyway so after the shampoo test had failed, one of us set of continuing molding with hot glue  even though most of us disliked that cup because of it’s ruff surface and simple form. We are humans and I guess we all like to drink out of a cup that looks good and looks clean, this is really important. But still we all agreed on that hot glue had the best characteristics on how it’s lit up. But when each cup take about more than a half day to produce it’s not a viable    solution, we need some material that can be molded and whilst being molded has some really low viscosity so it goes in to all holes and areas of our mold. It should also be easy to remove from the template, or the template should easily be broken off and reproduced.

In another part of our group we discussed what other materials you can fill the thermo cups (with dual layers). We came up with several ones mostly toxic ones though. But we also came up with the perfect candidate coconut butter because of it’s see through characteristics. But we also discussed that we could use glitter inside a fully see through oil of some kind. So whilst headed out to buy some great material we kind of got cold feet’s on buying toxic materials. Each user is going to drink from the cup and if anything leaks that would be a shame and dangerous situation. So after buying syrup and coconut oil which is both edible and has great qualities for this task we tried them out.

Syrup with glitter was quite a drag, it didn’t shine up any large area at all. Most light escaped directly out of our thermo cups from one spot. We need it to spread out on a surface as big as possible. And with coconut butter we had kind of the same problem but also it cracked when solidified. We also mixed syrup and coconut butter and glitter, that was the worst solution. Syrup and the butter didn’t mix, it was just a lot of droplets with butter and syrup. Looked awful.

And when the day was almost over we discovered that conditioner had perfect qualities. Even though it’s not edible it’s at least fire proof unlike other materials we had discussed. It also shined up pretty good.

Another problem discovered during the day, the thermo cups had a little too small space in between each layer. This might be the killer for this cup because the LED’s need a thick space in a single material to keep each ray inside the cup shell.

Conclusion is that our goal of having a working prototype today was toast, but we are working on it, and really hard also. The wifi network not mentioned at all in this post was completed and during the day tested with up to four units (simulated cups). So at least we had success doing something that day. // TB

That’s all for today/

More experiments

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Syrup + coconut fat and conditioner

Edible Alternatives

We’re experimenting with different materials, trying to find something that is non-toxic, will transport light but is not totally translucent. We’ve tried syrup and coconut butter this afternoon.

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