Final Project: Testing of Critical Elements

Today was all about testing key elements. For our project (music reader), these important parts were the photo cells and the mechanism that moved the sheet music (scroll) along.

1.) Photocells:

We first obtained 8 photocells so that the sensor mechanism can detect 8 different notes. We attached these pieces with Lego (the photocells are connected to Lego pieces). Jamie drew black circles on a white sheet of paper to check if the photo cells were able to report different numbers for when they detected white and black.

Our photocells (music reading mechanism)

We checked with the photocells to see how wide the scroll would have to be.

We drew black dots and gray dots (gray dots did not work well at first). On white, the numbers reported were in the low 800's, whereas on black surfaces, numbers around high 800 - low 900 were shown.

We then noticed that the photocell mechanism cast shadows on the white paper. To solve this problem, we thought we should build a "shield" around the photocell mechanism. However, this still cast a shadow, so we decided to use a LED light (flashlight) to make the surface (the mechanism would be focusing on) brighter.

We created this temporary "shield" with sticky note pads.

Our photocell mechanism with the "shield" (still temporary) and the LED light.

We tested the photocells to white and black surfaces.

We used PICO Cricket to program the photocells. 

Our program on PICO Blocks. We learned to program in text (versus using the blocks). We made the music reader (still in progress) chirp whenever the photocells detected light (number became greater than 550).

Conclusion:

We got to the point where we programmed four of the eight photocells to play a sound when it detected a light with value of more than 550. We also made it so that the four notes were different (in pitch).

2.) Scroll Moving Mechanism:

We had ideas of having a conveyor belt-like mechanism but decided to build a mechanism that would unwind and move the scroll (sheet music) along. 

We first tried to punch holes on the scroll ends and attach to these Lego pieces (scroll ends). But the pieces that stuck out prevented the scrolls from rolling in circles (there were occasional jerks in movement), so we tried to hold the paper in place by using paper clips. This method also failed because the paper clips were not secure (kept moving about the Lego rod). 

(Paper clip method did not work. This also created jerks in movement.)

Another problem was that we held the motor and the scroll parts to test the movement but soon realized this was not the best way to test this critical element. Therefore, we built a temporary base for the music reader with Lego pieces mainly for stability and to estimate the size of our music reader (since this scroll moving mechanism would take up the most amount of space). 

Our temporary base for the music reader.

We also realized there were jerks in the movement because the scroll was not long enough (we had taped two pieces of paper for greater length). Instead, we went to the library and obtained a longer piece of paper. 

(The video files were too great in size, so I could not upload them).

Conclusion: Obtaining a longer piece of paper (which we need anyway to have a full song) and the constructing of the base improved the mechanism and allowed for smoother movement.