Weekly Progress

Weeks 1-2

Several important thing have been done during weeks 1 and 2 of the Robot Symphony section. Our group has decided to create a Ultrasonic Levitation device. The end goal of this project is to allow the device to move small beads of paint up and down in response to MIDI input. All of the required electronic parts (transducers and motor controllers) have been ordered. The dome to hold the transducers still needs to be printed.

Week 3

This week the team received the transducers and motor controllers from their suppliers as well as 3D printed a version of the bowl that holds the transducers in alignment. In class, the process of checking the phases of the transducers will begin by using a variable power supply and an oscilloscope to observe the sine waves to make sure they match, marking each leg as a positive and a negative. Unexpectedly only 50 transducers arrived in the mail, instead of the planned 100 because of a bad description of the product, so only two levitation devices will be produced making sure that they will both perform flawlessly.

3D Printed Transducer Bowl

16mm 40 kHz Transducers

L298N Motor Drivers

Week 4

This week the team was able to begin actual construction of the ultrasonic levitation device. The first step is to ensure that all of the Transducers are in phase when they are put into the 3-D printed bowl. In order to do this the transducers must be connected to an oscilloscope 2 at a time. When the held up, oscilloscope will produce a square wave for the transducer that is hooked up to the Arduino and Motor Driver. The other Transducer that is just connected to the oscilloscope will produce a normal sine wave. If the two waves are aligned that means that the transducers are in phase and the ground needs to be marked, otherwise they are out of phase and the positive end needs to be marked.

Two transducers wired up and held together

Two transducers in phase

Two transducers out of phase

In addition to marking all of the transducer to ensure they are in phase, the team was also able to place all of the transducers into the bowl and solder them together as seen in the picture below. The next step to take would be to test the system to ensure that it is all working as intended.

3D Printed Bowl almost completely soldered

Week 5

After testing the ultrasonic levitation device in the lab setting we discovered several flaws that were causing the mechanism to not operate properly. We had mistakenly assumed that the Transmitting and Receiving transducers would produce the same signal when powered. We first had some doubts about this when we were checking the phases the first time. We saw that when we placed two transducers together, sometimes the sinusoidal waves were larger, while at other time they were much smaller. Often times we would have to go into finer resolution on the oscilloscope to determine the phase of these transducers.

After the ultrasonic levitation did not work in the lab setting we did some research and then realized our mistake. While the receiving Transducer can be used to emit sound, it is in the same way that a microphone can be used to play music. It is technically possible because of the way that the part is built, but it is not its intended purpose. Thus the weaker sound waves coming from the Receiving transducers did facilitate the formation of the standing waves needed to levitate a particle.

Once we came to this realization, we began getting to work removing the solder from the wire and transducers and re testing the phases, this time ensuring we only used Transmitting receivers.

New Re-Soldered dome, Arduino, and Motor Controller

Week 6

After the in lab testing during week five, we came across some problems in the device. Even though we had all of the components wired up correctly and the Arduino was programmed to control the transducers, we were unable to get an object to levitate. After doing some research, and look for other people that had done similar projects, we found what we think to the be the issue. From the DC converters that we have in the lab, we are only able to pull out a maximum voltage of about 18 volts, but to properly operate the device we would need around 25 volts.
One of the reasons we did not see this issue beforehand was that we were easily able to test most of the components at potential of 10 volts. This allowed us to test all of the transducers to make sure that they were emitting in phase and to make sure that the signal was going through the motor controller properly. but tit does not have enough voltage to run all the the transducers at the power necessary to create standing waves.
In order to fix this issue, we bought a DC to DC voltage converter that allows us to take in a DC voltage in the range of 5-34 volts and boost it up to a range of 6-36 volts. This way we can take any input power source, like a small LiPo battery and boost it up to the voltage needed to run the device.
After these changes were made, we were able to connect all the parts and have the device perform as intended.

Weeks 7-8

We have been attempting to integrate the movement of the bead with MIDI input. The challenge that we are facing with this goal is that the Arduino that we are using to control the Position of the bead cannot also be used to  detect MIDI input. We attempted to figure out a way around the issue by tweaking the levitation code, but we repeatedly hit dead ends. Eventually we decided to see if we could make contact with the original creator of the design. He was able to respond to our question and recommended that we use another Arduino to detect the MIDI input and use that to control the second Arduino.

We have tried using an Arduino Nano to try to trick the system into thinking that it is connected to ground, which is what the hardwired switches.  However, we are having issues understanding how the Nano would provide a ground for the Arduino Uno. However, we do have the code ready for the Arduino Nano once we are able to solve this issue.

Week 9

As of week nine we have our final working project ready for the concert. We changed from using an Arduino Nano to using a Teensy micro controller to make an easier time accepting MIDI as an input to the system. We finalized the MIDI code so now it will be able to hold the bead stronger in the low pressure zone caused by the standing wave. The bead can move for six steps meaning we can have a strong range of notes that will move the bead up and down without risking it falling. We also added a small cardboard shroud with a black light mounted to the top so the bead will be able to glow making it more visible. Here is a video of the working final design.