# Title Team Members TA Documents Sponsor
23 Educational Wind Powered Phone Charger
Lingxiao Mou
Maria Carrallo Escudero
Zixi Li
uma Lath design_document1.pdf
#Educational Wind Powered Phone Charger

## Team Members

Lingxiao Mou(lmou2)

Zixi Li(zixili2)

Maria Carrallo Escudero(mariac7)

## Problem

As more industrial company turns into cleaner energy utilization, wind power has become one of the main power source for energy supply. From industry point of view, it would be a good idea to teach students how this technology is used in real world life. One of the critical issue remains unresolved is the consumption of electricity when traveling with bike. Since bikers prefer to ride a mountain where temperature is relatively low and electricity is hard to be resupplied, a charging tool that can supply power to phone would be necessary. Although there are commercial products available, they are not operational during when having a rest, not adjustable for wind speed, and expensive

## Solution

Our solution to supply power is to build a wind power phone charger that is able to change pitch. The rotor and blade will automatically regulate or boost power production by modifying the pitch angle.The wind turbine system will be mounted at the front of the bike on head tube.

## Solution Component
- Blade: We are planning to make 3 blades with approximately 18 centimeters length. We are assuming it has normal air density with
1.2 kg/m^3(temperature=20 celsius). We also assume the efficiency would be 40%(the optimal wind conversion efficiency is 0.59, but we are considering certain errors). The power could be generated can be calculated by P=½ * r² * v³ * ρ * η=7.4 watt. While the power needed for charging a phone ranges from 2 to 6 watt, which is inside the range of our power production

- Servo: We are planning to install 3 servos. 3 servos would be used for changing the pitch angle of blade. The servo will operate by checking the wind speed reading from anemometer or flow sensor. Depending on the reading, there will be at least 3 turning angle for servo, including 0, 45 and other angles remaining for testing to ensure the greatest efficiency. The reason for having a 0 angle is to prevent extreme severe wind condition damaging the blade by allowing wind to directly pass through the blade parallelly.

- Anemometer: The device is used to detect wind speed for servo to change their angles. There are couple of options to use. We might use a heat anemometer(, or we might use Adafruit anemometer. Or we will build an anemometer by using interrupt pins on microprocessor to calculate rpm of fan and speed.

- Generator: By assuming 3 blade(TSR) and 15 mile per hour(=6.7m/s) bike speed and 18 centimeter radius, I can calculate the rpm by 60 * V * TSR / ( Pi * Diameter )=60*6.7*6/(pi*0.36)=2132.67. Based on this calculation, we might choose any generator that can reach this value, for example( The Kv for this generator is around 250/3 rpm/V, making our final output voltage be around 12 V, which is also in the range.

- Microprocesser: We will use ATmega328P for pitch angle control and might use its interrupt function for wind speed calculation. When anemometer detects the speed change into specific range, it will notify the servo to let it change pitch angle.

- Manuel control: There would be a power button for this system that allows entire system to start working or halting.

# Criterion for Success
- The system is able to charge phone
- The system is able to change pitch based on wind speed automatically
- The system is able to be mounted on bicycle.
# Envision of Final Demo:
All system will be mounted at the front of the bike on the head tube. If Adafruit anemometer is used, it will be mounted at the back of the bike for having more space. We will ride the bike around and show that phone battery electricity is increasing.


Srinija Kakumanu, Justin Naal, Danny Rymut

Featured Project

**Problem:** When working out at home, without a trainer, it’s hard to maintain good form. Working out without good form over time can lead to injury and strain.

**Solution:** A mat to use during at-home workouts that will give feedback on your form while you're performing a variety of bodyweight exercises (multiple pushup variations, squats, lunges,) by analyzing pressure distributions and placement.

**Solution Components:**

**Subsystem 1: Mat**

- This will be built using Velostat.

- The mat will receive pressure inputs from the user.

- Velostat is able to measure pressure because it is a piezoresistive material and the more it is compressed the lower the resistance becomes. By tracking pressure distribution it will be able to analyze certain aspects of the form and provide feedback.

- Additionally, it can assist in tracking reps for certain exercises.

- The mat would also use an ultrasonic range sensor. This would be used to track reps for exercises, such as pushups and squats, where the pressure placement on the mat may not change making it difficult for the pressure sensors to track.

- The mat will not be big enough to put both feet and hands on it. Instead when you are doing pushups you would just be putting your hands on it

**Subsystem 2: Power**

- Use a portable battery back to power the mat and data transmitter subsystems.

**Subsystem 3: Data transmitter**

- Information collected from the pressure sensors in the mat will be sent to the mobile app via Bluetooth. The data will be sent to the user’s phone so that we can help the user see if the exercise is being performed safely and correctly.

**Subsystem 4: Mobile App**

- When the user first gets the mat they will be asked to perform all the supported exercises and put it their height and weight in order to calibrate the mat.

- This is where the user would build their circuit of exercises and see feedback on their performance.

- How pressure will indicate good/bad form: in the case of squats, there would be two nonzero pressure readings and if the readings are not identical then we know the user is putting too much weight on one side. This indicates bad form. We will use similar comparisons for other moves

- The most important functions of this subsystem are to store the calibration data, give the user the ability to look at their performances, build out exercise circuits and set/get reminders to work out

**Criterion for Success**

- User Interface is clear and easy to use.

- Be able to accurately and consistently track the repetitions of each exercise.

- Sensors provide data that is detailed/accurate enough to create beneficial feedback for the user


- Designing a circuit using velostat will be challenging because there are limited resources available that provide instruction on how to use it.

- We must also design a custom PCB that is able to store the sensor readings and transmit the data to the phone.