Category: 2. Prototyping
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.
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/
Syrup + coconut fat and conditioner
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.
Images on the first designs and tries with touch sensors…
Our mockups are starting to look more and more like a finished prototype. But today we didn’t really miss out on troubles.
First of we all met and tried to divide the work as usual, and set of in the normal tasks:
Wireless – network (code implementation)
Touch – sensors (hardware circuits)
Cup design (melting and prototyping)
Each task had their different problems or difficulties.
Wireless had problems with timer interrupt and wifi-receiver interrupts at the same time, but after a while got it solved. Still more to do in this task, have to combine all of the code and have them share all their knowledge as a table in each transmission.
Touch had difficulties with the NOT gates, they didn’t give enough hight on the wave-forms produced. And after a suggestion from Farshid we used a IC 4093 (NAND gate chip) which have the functionality of waiting until each NAND gate is fully decharged, which gives a much better wave form to each sensor circuit. After further soldering, we implemented this also in todays prototype cup, and got it working perfectly. Also a piece of code was produced that adjusts to the normal value of each sensor circuit. Due to that every piece of metal or wire adds to the response of that touch sensor; therefor we cant use predetermined values to adjust to.
On the area of cup design, we first headed to town and bough a melting template to use to get a better sized shape on our cup. Whilst producing the inner layer out of paper and overhead plastic we also soldered the circuit for eight RGB LED’s and some sensors that we glued to the inner sides of the template (made out of overhead plastic, put inside the glass template). This went perfectly but with the melting we had problems with coloration of the hot glue, maybe due to a overheated heating process. We had also problem getting the glue inside the template perfectly, which none of us really didn’t like. Even though the prototype looked great with turned on RGB LED’s, no one would ever dare to drink out of that cup.
After all those problems our minds where not really set to continue with this project. But two of us went down to the town anyway to get a better inner template. But at the store we found these thermoses, which had dual layers that would be great for our project. That is what we will be working with on Friday (I’m just guessing).
Thank’s for today anyway, we can call it educational even though everything! // TB
In our way to reach awesomeness with this project we all had different ideas on how to light up the cup, but no one of us in the group knew which way would look the best. So we divided us up and made a couple of different mockups, which would provide some background to a decision on which method to go for. As you might have noticed our big melt showed the best result, lighting up more than half the way down the cup. Now we just need LEDs in the bottom of the cup, which will make all of the cup light up.
Another team in our group set of trying out the touch sensors even more. Which resulted in the design decision to only have a small number of spots where it would sense touch, instead of exactly positioning each finger on the cup and comparing them. This new approach is better for our small processing unit and also simplifies the problem.
Another test we did was to melt in the sensors inside Lighting Prototype #3 which gave good results. Whilst doing all this we also got some new ideas on how to sense touch without stalling the processing unit from doing anything else. That’s whats planned for Wednesdays work.
Hope you like the pictures // TB