Recorder Problem Solving

During the tests run in the previous lab, it was found that the quality of sound was poor, screechy like child learning the recorder and not an instrument fit for a symphony. The first proposed solution was changing the air pressure released from air compressor, however after this failed to solve the problem, we moved on to investigating the seal of the solenoids over the holes of the recorder. This led us to use foam earplugs instead of the original rubber stoppers to ensure a better seal over the holes.

Week 9

Weekly Objective - This week is the dress rehearsal and final symphony performance. The construction and algorithm are complete so now the only thing left to do is test and ensure that the recorder works cohesively with the MIDI and the other instruments.  

Design Lab

In lab today our instrument was checked by our advisors to ensure that it was fit to be a part of the final performance. Emily and our advisors made sure that our instrument was compatible with the master code and Kevin fixed some minor problems with the air supply system that were causing some squeaking.  Jessica began working on the outline for the final presentation and Allie updated the blog with all the progress we’ve made in the past week.

Arduino Programming

Last week every group was given code to use that will allow the main computer to communicate with each instrument. We worked closely with our lab instructor and TAs to cater this code to the recorder and the way it uniquely functions. Essentially the the code works is that the main computer sends a midi note and note duration to an instrument. For each midi note, a combination of the recorders solenoids will turn on or off for a duration. When that duration is over the pneumatic solenoid will turn off and no sound in the recorder will play because there will be no air supply.

Frame Construction

Today Kevin, Jessica and Allie Spent the afternoon and evening completing the frame construction. First, two semicircular divets were sanded into the wood in order to lower the recorder to the same level as the solenoids on the sheet metal. This allows for the solenoids to reach the recorder holes. The recorder was then secured to the frame using bent hose clamps. Finally, the solenoid, relay board and arduino then attached to the sheet metal using steel epoxy. Tomorrow the wires will all be reconnected and soldered. The final prototype will then be ready for final program testing and troubleshooting before Wednesday. 

Week 8

Weekly Objective - This week we are finishing the construction and soldering of the final product. By Wednesday's design lab we will have our deliverable for fine tuning and a final audition. The robot's mechanical function and program must work by the end of lab in order to participate in the robot symphony next Friday.

Arduino Programming

We have just been notified by our advisors that each instrument in the symphony will not be controlled by its own program, as we had previously been led to believe, but that they will all be controlled by a single midi program running on a single computer. The main program will ensure all instruments keep tempo and play the correct notes at the correct time. However, this means that all the code and calculations previously done will not be used in the final performance. Instead we will need to edit the code written by our advisors to fit our instrument. Because the code was written for a xylophone type instrument, the code will have to be changed significantly to accommodate the recorder, as the example code was for a xylophone. 

                                                                             Frame Construction

Today at Drexel's machine shop and the innovation studio the legs, structure, and shelving were constructed as shown in the picture to the left. Tomorrow in Design Lab we will deconstruct our previous prototype in favor of mounting it all on the new frame. While this means that we cannot play notes for this weeks lab, it also gives time for Emily to reprogram the arduino. Hopefully everything will be assembled and we will have a final product next week for the in class rehearsal at the ExCITe center. 

Gathering Materials

Today Allie and Kevin went to Home Depot for frame supplies. We purchased screws, washers, square dowels, JB Weld, more hose clamps and perforated angle iron, all of which will be used to construct the frame support in the next few days. 

Week 7

Weekly Objective - This week we plan to dismantle the foam-board prototype and attach the recorder and electrical components to the newly-built frame. We also plan on changing the programming to reflect the changes our advisors recently made to insure smoother collaboration with other instruments.

Frame Design

After in-class testing, we discovered that the solenoids generate a bit of heat after a couple minutes of constant usage. We completely redesigned the frame for easier construction and planned the new shelves for the solenoids to be made of sheet metal, which will serve as a sort of heat sink and distribute the heat generated by the solenoids over a larger surface area.

Week 6

Weekly Objective - This week we were assigned our part for the first movement of the symphony piece that we will be playing. We will begin to work on the programming for these notes and fine tune the wire connections in the circuit (so they don't have to be held together by hand).

Week 6

Weekly Objective - This week we were assigned our part for the first movement of the symphony piece that we will be playing. Finishing the frame, programming the correct notes/note duration, and fine tuning different circuitry elements is the primary goal for this week. As the final performance is in less than 3 weeks, we hope for the project to come together by the end of next week so that we have a whole week (Week 9) to tweak and perfect the instrument. 

We attached the solenoid, air pressure system, recorder, arduino and relay to a foam board temporarily to hold each component in place, which allows us to begin testing codes on the solenoids to see if they can accurately plug the holes of the recorder. This board will be replaced in the next few weeks with a wooden frame. 

Frame Design

This is the preliminary design for the structural frame that will house the recorder and all of its electronic and mechanical components. This design is a four sided open box design, which simultaneously allows for all the structural components to be attached and so that a viewer could observe the inner workings of the instrument. In the design, in order to maintain access to all holes on the front and back of the instrument, the recorder will be turned sideways, so all push solenoids, the arduino and the relay board can be mounted on either side of the recorder on shelf-like platforms. 

Week 5

Weekly Objective - This week we are working on integrating the push solenoids into what we already have accomplished thus far. As we now have all the components and dimensions of each project element, we will also begin working on the frame design to more create a more stable and permanent mount for all electronics and the recorder itself. 

Circuit Design 
This is the revised version of the original circuit diagram of the pneumatic recorder. Small mistakes (unnecessary connections between each solenoid, missing connections to the common terminal in each relay, and errors with the input/output pins on the microcontroller) were fixed and the diagram now accurately represents what is actually going on electronically with our current working recorder prototype. 

Testing

During testing today, the device exhibited issues with back pressure. When the solenoid valve is closed during a rest in the music, the air hose pressurizes to its maximum behind the valve. When opened again, a sudden surge of air floods the recorder and produces a loud, undesirable noise. To combat this, wadding was stuffed inside of the 1’’ tubing to reduce the velocity and volume of the air reaching the mouthpiece of the recorder, much like a pop filter is placed in front of a microphone to slow down the air from sharp sounds like “P” and “B”.

Testing
In order to test the function of the air pressure and release system, Hot Cross Buns and Mary Had a Little Lamb were programmed in lab this week for timing in air release. Because the solenoid system is not yet complete the songs were tested by programming air release times and team members playing the notes. 

Hot Cross Buns

Mary Had a Little Lamb

Shout out to Kevin for carrying a 3 gallon, 70 pound air compressor around campus all day so that we could use it in Design Lab to test the recorder! 

Week 4

Weekly Objective - This week we are focusing on fine tuning the connection between the air compressor and the recorder, as well as testing different timing functions through programming. We are also working on the CAD design for the frame which holds the recorder, a structural support which will be constructed after determining how much space above and below the recorder the solenoids will need to rest. 

Music Selection
We also were introduced to the piece of music which our Lab Section will be playing. It is a medley of iconic soundtrack songs from the Harry Potter movies. Emily determined from the music that the recorder will be unable to play D# and C#, which are the only obvious restrictions of the music as the hardware can handle the speed of even the fastest sections.

Circuit Update
This week we started working with the relay board, the pneumatic solenoid and the arduino, which make up the majority of the air supply release system. Using an example blink function pre-programmed into the arduino we were able to test the opening and closing of the solenoid once properly wired to the relay board. The circuit is temporarily powered by a 12 volt, 4 amp power supply. Now that the circuit is set up, we are now able to determine the maximum speed that the pneumatic solenoid will be able to open and close, thus releasing air into the instrument. The speed of firing for the solenoid was pretty fast and the circuit therefore has an electrical capacity to play any possible note duration for any given song. What we have this week is a solid working proof of concept, and is a promising step forward in the circuit design because it shows that the original circuit diagram (that you should include in last weeks post) is feasible.

Arduino Programming
We tried figuring out a way to incorporate a BPM to milliseconds calculation for a variety of note durations so that we could change BPM at will and therefore simplify our delay usage, as is shown on the left. However, it seems that delays only take integer inputs and don't accept variables. This idea was scrapped, so now all delay duration calculations will be done by hand and input into each delay as an integer value. This section was removed and we started manual calculations  of how many milliseconds each note duration would equate to.

Week 3

Weekly Objective - This week we are starting to work on the air supply programming and ordering the push solenoids. As we collect the necessary electronic and mechanical parts for the recorder we will work on what we can with the materials we have in preparation for next week's upcoming deadline to produce sound with our instrument. Hopefully by next week we will have an arduino controlled air system, even if we have to play the notes by hand. Once we have the seven push solenoids, the goal will be to actually test specific notes.

Arduino Programming

This week we acquired our arduino from the ExCITe center during Design Lab and Emily began coding. To start off the arduino programming, we checked out some arduino citation, at https://www.arduino.cc/en/Reference/HomePage . First, we needed to figure out the pin assignments on the arduino. It was decided that pin 1 would be the pneumatic solenoid on the headpiece, and the remaining 7 pins would be assigned to 7 of the holes on the recorder. Once assigned we could start writing up the solenoid combination needed for each note. The end result for a given note looks something like this:

In this case, D4 (the first D above middle C) requires that all the solenoids be on, plugging the recorder holes. This is done by setting that pin to "low" which switches the relay into its open position and pushes the solenoid down.

We repeated this for all notes playable by our recorder, changing pin settings to "low" or "high" depending on which holes need closed or open, respectively.

Week 2

Weekly Objective - This week our Design Proposal  for the recorder will be handed in and reviewed. In class we will discuss the logistics of fabrication and meet with our project advisor to resolve any issues. Outside of lab we will continue to do mechanical and software related research as well as begin ordering parts we need and collecting those we have.

Circuit Design 

This is the preliminary circuit design of the project. It shows the rough plan for the connection of the pneumatic solenoid and the 7 push solenoids (top) to a relay board (middle) and an arduino microcontroller (bottom), as well as several outside power sources. This design still needs to be looked over and reviewed for mistakes and possible improvements. 

Timeline: This table shows a tentative timeline of activities for the completion of the pneumatic recorder. The recorder must be finished by week 8 in order to perform with the robotic symphony at the URBN Center Black Box Theater on May 27th, but will be presented individually Week 10. 

Budget: The estimated budget for this project is broken down into Mechanical Structure, Pneumatics, and Circuit Materials to account for the vastly different fabrication of each system. Most of the parts listed were found on Amazon or Home Depot's website. The items that were priced at $0 we either already own or have access to borrow.
   

Week 1

Weekly Objective - This week is dedicated toward planning the logistics of our design project. This includes conducting background research, creating a preliminary circuitry, mechanical, and programming design, and forming a tentative timeline/budget for the project.