|23||Educational Wind Powered Phone Charger
Maria Carrallo Escudero
|#Educational Wind Powered Phone Charger
## Team Members
Maria Carrallo Escudero(mariac7)
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
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(https://moderndevice.com/product/wind-sensor/), 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(https://www.amazon.com/Cutting-Edge-Power-Turbine-Generator/dp/B07FVJGVQ8?ref_=ast_sto_dp). 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.