Science and Mechatronics Aided Research for Teachers with an Entrepreneurship Experience (SMARTER)
2014: Week I
David Arnstein
The first day was as introduction to the SMARTER program. We saw examples of projects done under the 4 week format (many focused on creating a "teaching/learning lab") and also some under the new 6 week format (projects grow out of actual engineering research). It became clear that opportunities for original and creative research are everywhere and encouraged. The cohort met the head of the mechanical engineering department who reiterated the importance of STEM education. Through one “surprise activity” we understood what we are likely to learn during the next two weeks. A second surprise was offered when we went into the lab to complete some surveys: boxes of "toys" – microcontrollers, sensors, various kits, and manuals for assembling projects.
Lunch was stupendous: 70 minutes to browse local eateries, enjoy the sunshine, and consider all the work ahead of us (research paper, powerpoint presentation, curriculum creation, weekly notes (daily for first two weeks), lab internships, and, most likely, additional expectations not yet revealed.)
Post lunch we had a short lecture on resistors, batteries, Ohm’s law, and simple circuits. Then we went to the lab to build and test these circuits. We checked out accuracy of resistor color bands by confirming with Protek Multimeter set up as Ohmmeter. The last step was applying voltage to the board and measuring amperage and voltage throughout the circuits we built.
There were some problems with our ammeter setup so it was not possible to verify the Ohm’s law by measuring both voltage across and amperage through the resistors, but we calculated expected amperage based on measured voltage drops and known resistance. When we borrowed an ammeter from another group, it was possible to verify the Ohm’s law. All groups seemed confident in using components, multimeters, and breadboards to build simple circuits. The final circuit used a variable resistor in parallel with a second resistor to control the output voltage at two points of a circuit. By building the circuit and using a voltmeter at the output locations, it was easy to set the dial to create a desired output. Mathematically, it was difficult for some to calculate the needed resistance, and this calculation was demonstrated to the group by our instructor.
Other highlights of the day included: air conditioning being repaired/replaced made for heated and exciting research into circuits. With any luck, future experiments will be somewhat cooler. Also, we were visited by the Director of the Center for K-12 STEM Education who mentioned that there are several other programs running this summer - including students placed in research labs - and that there may be opportunities for live webcasts or other promotional activities.
Michael Zitolo
Jared kicked our second day off with an overview of Mechatronics, a field that encompasses Mechanical, Electrical, and Computer Engineering as well as Control Theory. One tool frequently used by research scientists in this field is a microcontroller. We reviewed the components of a microcontroller and how a Basic Stamp is programmed. Following the lecture, we were given time to practice programming the Basic Stamp to do very simple tasks, such as using it to make basic calculations and print statements and variable values to the Debug window in decimal, binary, and hexadecimal.
After lunch, Jared explained the science behind and uses of diodes, whose many applications include use as rectifiers and voltage droppers. He also discussed LEDs and how to safely use them in a circuit using appropriate resistors. We then ventured back into the lab practice using the Basic Stamp to light and manipulate LEDs. By the end of the day, were able to use the Basic Stamp to control multiple LEDs simultaneously. We also figured out how to control a 7-segment LED-display to display numbers and letters. In terms of programming, we learned how to use FOR...NEXT and DO...LOOP to accomplish these tasks. It was a productive day!
Ulugbek Akhmedov
Today, we learned a great deal about buttons and switches. Some stuff was pretty straightforward. A few details follow.
Different types of switches/buttons were used for placement on our breadboards. Four pins of the buttons allowed it to be stabilized on the breadboard. The four pins of the button are internally connected in two pairs each, so that the pins within the pair have the same potential.
We were provided buttons that act as momentary switches that allow either temporary ON (or OFF) position under user action and when user action is removed it reverts to its default OFF (or ON) position by a spring inside the button. That is, our momentary buttons do not allow permanently switching the position - it always returns to the default position. Button can be normally closed or normally open, i.e. normally ON or normally OFF. The following is an illustration of a button we used.
There also exist switches which can permanently change the position from one to another. A switch can be "thrown" from one position to another. It can also open and close two or more circuits simultaneously. A switch can also open one circuit in a particular position while having a different circuit closed.
Limit switches can be used to limit certain action: motion, pressure, rotational motion, switching the direction etc. these can be used in robots to sense and respond to mechanical obstacles, conveyors to count, or switch On and Off for particular parts to be sorted etc.
Once we got to lab we had an opportunity to build and test simple circuits with switches.
We then learned to program the microcontroller and construct circuits so that we work with a button and control its default setting to be either On or Off (i.e., active low or active high).
Later we used our electronic kits to charge and discharge small capacitors. A capacitor is used to store electric energy as charge, analogous to a mechanical spring that is stretched (or compressed) by external pressure. Voltage is an electrical analogy of the mechanical pressure.
In case of polarized capacitors it is important to connect them with proper polarity. Just like in case of LED lights, the longer "leg" should be connected to + of the Voltage source (Vdd on the electronic kit.)
The microcontroller was next used to determine the discharge time of a capacitor. RCtime is the time it takes to charge or discharge a capacitor. It depends on the capacitance and the resistance in the circuit.
We found that for 3300 microFarad capacitor the time was 1.1 second and for 1000 microFarad, it was 0.4second. These times are lower then expected from the product of R*C. However, we knew that the program would equate any voltage below 1.3 V to zero and stop the timer.
For even smaller capacitors, it was possible to program the timer so that it would read the potential on a capacitor relative to the ground in 2 microsecond intervals. This gave us around 300 microsecond time which is inconsistent with calculations. So we should go back tomorrow and check again.
Finally, we tested the sensitivity of a phototransistor to light by varying the illumination of the filaments and reading the time the capacitor takes to discharge. The greater the illumination the shorter time it took for the capacitor to discharge. This is due to the fact that the photo-element functioned as variable resistor in RC circuit, and the variability of the resistance was dependent on the amount of light.
It was a great day. It feels we are accelerating the rate of learning!
Prasad Akavoor
We started the day with a lecture on optoelectronics (“Lecture 6,” on the SMARTER website). We discussed photoresistors, photodiodes, phototransistors, and their applications. Light sensitive voltage dividers, switches, and relays are some of the applications we discussed. After the lecture, we had a better understanding of how yesterday’s experiments with the RC timers worked. We started working in the lab again and some of us continued to work on projects we had not completed yesterday. Some others proceeded to Chapter 7 of the “What’s a microcontroller?” manual and started building the circuits to measure light and programming their circuits.
At 11:00 we broke for lunch, which was a grand event – New York City Schools Chancellor Ms. Carmen Fariña was keynote speaker. Dr. Kurt Becker, Vice Dean of Academic Affairs, spoke briefly about NYU’s K-12 outreach programs.
Professor Vikram Kapila’s welcome remarks followed Dr. Becker’s. Professor Kapila told us about how the K-12 program started and how it has expanded to the present size. He mentioned that there has been a significant increase in the participation by students and teachers. As a result of the program, Professor Kapila said, teachers have been able to take many invaluable STEM related ideas into their classrooms and to enhance their teaching. A three-year study showed that students greatly improved their science and engineering scores as a direct result of active involvement in NYU’s K-12 STEM education programs. The NYU program has been instrumental in helping teachers take robotics programs into the classroom, for example. Ben Esner, Director of the Center for K-12 STEM Education, introduced Ms. Fariña. He recalled having worked with Ms. Fariña and told us about their joint effort in helping kids with autism and about their involvement in PS32. Ms. Fariña thanked everyone and assured the audience that NYU has a partner! “We need to be partners,” Ms. Fariña said, “so principals and teachers know that we are serious about STEM education in the city.” Her goal, she said, was to make NYC the largest city in the nation that makes a difference in STEM education. “We will get parents involved,” Ms. Fariña told the audience.
The lunch menu was fabulous and included a vegetarian option, too!
The afternoon session started in the lab. Most of us worked on a unit called “Frequency and Sound,” Chapter 8, of the “What’s a Microcontroller?” We created music by programming the BS2 to control a piezoelectric speaker to produce notes of different frequencies. There are many, many projects one could do using the programming tips given in the manual. Some of us got ourselves familiarized with subroutines on the BS2, while others successfully synthesized music (Beethoven’s 5th and 9th!) digitally. A few groups learned how to build and program a light meter gizmo using different RC constants. Jared gave a presentation on thermal sensors (DS 1620) and accelerometers (AD 592). We built and programmed a digital thermometer. We thought some of the documentation on the BS2 programming needed clarification. The program we found online didn’t really explain what some of the variables, constants, and operators were. However, the programs instructors clarified these issues for us.
Angeleke Lymberatos
Today was an exciting and innovative day. We worked on a wide array of activities. We began the day using the 555 Timer to generate frequencies in the audible sound range, using the BASIC STAMP to sample and process the frequency data. We built the circuit and adjusted the potentiometers until the speaker made a steady, slow tic-toc sound. We generated an output of the 555 Timer Pulse Train.
During the afternoon we continued to work on the Basic Analog and Digital Activities. We built the Analog and Digital Comparator. Then we created a code to display the output as 1 or 0. By adjusting the potentiometer the LED light changed brightness. When the LED was bright the display or output was 1 and when the LED was off the output was 0.
Later on we worked on Transistors, which are probably the most important device in a circuit. A useful analogy that was discussed in class was comparing a Transistor to a faucet. When controlling the valve, it allows a certain amount of current to flow through the system. We created a digitally adjusted potentiometer. We ran the code, which adjusted the resistor and changed the LED’s brightness.
