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This week, we finally saw the completion and fruition of what we’ve been working towards from the beginning of this DukeEngage journey – our engineering lesson plans. We have been working on these lesson plans even before we left Duke for the summer. The lesson plan was to have a biomedical engineering focus, and be a fairly difficult project for middle school. My lesson plan and project was building a pulse sensor circuit.


The Pulse Sensor

My lesson plan involved building a circuit that could detect pulse and make an LED blink in time with it. It was adapted from a lesson plan from Ohio State University’s freshman engineering projects. I and my partner Siera built the sensor part, using a potato chip bag clips that held an infrared LED and photodiode. The IR LED emits infrared light through the thumb and is detected by the photodiode. The amount of infrared that is detected varies with pulse, and the circuit interprets that information and makes the LED blink with the pulse. The students were to build the circuit, which was moderately complex, and involved various resistors, a dual op-amp, and two potentiometers.


The Class

Although with a biomedical focus, the class focused on two main goals. The first is to learn about infrared and pulse, and the second is to learn how to build a circuit. For many of the girls, this was their first experience with building an electrical circuit. We started them off with a simple circuit, which turned on an LED with some paperclip switches. Then we moved on to the more complex pulse sensor circuit. Many of the girls found it very challenging, even with our efforts to guide them step by step.


I think it was very important for the girls to learn about the part of engineering that isn’t always creatively imagining, but following defined steps meticulously and self-checking errors diligently. As an electrical and computer engineering major, it was also important to me that they learned about electrical engineering. The girls used real wires, real batteries, real breadboards and other real circuit elements. We had a few sparks and smokes, but it was cool to see the girls experience real engineering.