Final Project, III: Figuring The Jaw Out

       The first thing I did next class was build a new jaw out of Lego. This was a little too puzzling to me for some reason so I decided to examine A.L.F.I. for some clues. I also read the blog on its development. Then, I consulted Lyn and finally built a hinged jaw. The result was quite simple and I was a little embarrassed bacuse it took me so long to wrap my head around it. I quickly moved on to the programming part for now.

       The biggest challenge I had also became apparent after a chat with Lyn. I had assumed that we can record ourselves talk, program the NXT using these files and the sound would come from the brick. Well, it wasn't that easy. We didn't even know if the NXT could play such sophisticated sound. We had heard it only beep and play the short start-up melody so far. Lyn suggested that I program the NXT to send a message to a device that can play music via Bluetooth. He said he could supply me with an android phone or something of the sort for playing the sound files. Therefore, I started doing my research on how to get an NXT to play a sound file and alternatively communicate via Bluetooth. By the end of the class, all I had visibly accomplished was make the NXT play a barely audible 'Is this working? What the hell!?' in my voice when İts button was pushed. That was far far away from my goal but I learned a lot of things during this class. I learned that the sound file type for LabView is rso and got the software for converting other types of sound fıles to this. I also got softwares for recording and changing sound. Additionally, I tried using text-to-speech software for creating a robotic and creepier voice but this did not work. I also started my work on deciding on phrases. The end of the class dıd not look hopeful but I knew we would figure it out. I knew we had to because Deepika and Lisa's project depended on being able to play music. Chris was out of country and Lyn said he would look into it. I remember that I left the class thinking this will be harder than I had thought.

        I decided to focus on the building of the jaw until I had more information on how to make the NXT talk. Around the same time, I sent my team mates a list of the possible phrases for our puppet and asked them for their opinion. Together, we decided on the following sentences:

Hello!
Hmmm... interesting!
Tell me more...
Come closer...
And how do you feel about that?
        The last one got eliminated later because it was too long and we didn't have enough memory space on the NXT brick to put all these files. We replaced it with a 'Hi!' as an alternative to 'Hello!'. The jaw wasn't as easy, unfortunately. Another helpful chat with Lyn guided me in building the jaw in SolidWorks. I was really excited because I found out that we could use the 3-D printer for our jaw. After a few hours, I had a part I could print. Or so had I thought. Now I had to figure out how to put an axle, specifically a Lego rod, through it. I reasoned that getting an extruded-cut on the jaw in the shape of the rod's cross section would give the expected result. I talked to Briana on Lyn's suggestion because they had made circular holes for these rods. She gave me the diameter of the hole and I used that to build a cross on a rectangle. Lyn had advised me to try the hole before I print out the jaw since it is a long and expensive process. So I printed a small cube with a hole in it using the 3-D printer. This took us about half an hour but unfortunately it didn't fıt. So I tried again, making the hole larger by 0.1 mm on each side. This did not work either. My next trial involved three pieces, each larger by 0.05 mm than the previous one. Trial 3 also failed. I got better results on the fourth trial with three pieces. The smaller two pieces could be pushed on to the axle with lots of force and the largest one fit very tightly and well with relative ease. This larger axle with 1.85 mm sides made me very happy:

Success!

      After a little resistance from SolidWorks, I was ready to print the jaw. We had about a week left and needed to speed things up. When we oriented the jaw for most efficient printing, however, the orientation of the hole changed. We didn't know if the dimensions would still be right this way so we printed the right-sized cube in this orientation to find out. The result was disastrous, mostly because of the debris that had piled up around the tip and in the bottom of the printer. Lyn cleaned it up and we decided to print it in the less efficient orientation that was sure to give us a correctly sized hole. This took a whole night. I learned how to use the base bath and put the jaw in there so the support material would melt. It looked like this before the bath:

Fresh out of the printer!

         While it was getting ready in the bath, I had other things to worry about, like giving it a head...