Testing of Cooling System:
- Cooling From Humidifier and Fan
- Humidifier Testing
Figure.1
The amount of cooling that the atomizer can provide is not significant. There is little decrease in temperature over time, where the starting temperature was 23℃ and the end temperature 20℃. The relationship between the relative humidity and the temperature is observed in which the temperature decreases as the humidity increases. The testing location was in a closed room room with a temperature of 23℃ and a relative humidity of 30%. The amount of temperature decrease in less humid environment has not been tested due to the lack of available environments with hot and dry climates.
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- Fan Testing
Figure.2
Implementing the cooling system with both the humidifier and fan, there is no notable decrease in temperature around the immediate area. The final temperature for the the testing process resulted in 20℃ with a relative humidity of 30%. The fan did not improve the performance of the cooling system. The distance from which the temperature and humidity were read was seven inches from the fan. The lack of improvement from the fan might be due to the fan imprecisely distributing the misting area onto the measuring system. Testing four fans with a humidifier simultaneously hasn’t been tested yet, there is no expectation that the amount of cooling will improve drastically but the multiple humidifiers could decrease the temperature by increasing the humidity.
- Lifting Range of Water Pump
| Lift Range(inches) | Water Rate with Regular Water | Water Rate with Chilled Water |
| 47 | 8.89ml/s | 6.67ml/s |
Table.1
The amount of lifting range for the water pump meets the requirement of the height for the umbrella. The water rate is acceptable for the purpose of damping the sponge in the cooling system enclosure. There will have to be some manipulation of how long the water pump has to be on in order to prevent the cooling system inclosure from overfilling. The change in water rate for chilled water was surprising, where the water rate decreased.
Testing of 3D Printed:
- Handle and water pump support
The water bottle support is fully designed and printed out into two parts. In testing these parts each part did not break in stress tests and drop tests. In our first test we dropped each part from 5 feet 3 times to see if they break at all in which we did not see any damage. The reason we chose 5 feet was in everyday use these pieces shouldn’t be dropped from a height higher than 5 feet. In addition, we tested these parts by using them in similar ways the user would and no issues came up where they would break off of intended use.
Figure.3 Figure.4 Figure.5
- Ferrule
The ferrule testing is mainly focusing on the PLA material durability vs. infill density. When the sample ferrule’s infill quality set as 20% the ferrule is durable and the printing estimating time is 11 hours and 25 minutes. To do the compareation, I printed the same structure with an infill density of 10%. As a result, I got a printed ferrule with a similar durability and a lower printing time. For the10% density structure, the printed time reduced to 7 hours and 20 minutes. Therefore, for the further printing of the Ferrule part, The printing value should set as 10% infill density with the octet pattern.
Figure.6 Figure.7
Testing of Power System:
- Voltage output of both the batteries and solar panels were tested. The 4 solar panels were connected in parallel with a voltage output of 8.5 volts. The voltage output of the batteries were 3.56 volts each.
Figure.8
Testing of Control System:
- The raspberry pi can request data from the dht11 and use it to turn components on and off. This currently works for the dc motor and the humidifiers. The pictures below show the setup used to test the code. LEDs were used at the time to test the code and make sure pins were turning on and off at the correct times. Both pictures are while the code is running. Red was being used to test the DC motor’s pins and Yellow was for the humidifiers. The DC motor is using pulse width modulation to turn on and off.
Figure.9 Figure.10
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Humidity and temperature detection
The device needs to be able to detect the humidity and temperature of the surrounding area. The part of the design requires high sensitivity and veracity.
Approach: We will be using a DTH22 which is a temperature and humidity sensor. This sensor can operate with a 3.3-6v DC power supply. The sensor can operate within -40~80 °C. The sensor can only send data every 2 seconds, but this should not become an issue in the final design. The sensor costs $15. This sensor is both precise and cheap.
Data receiving and system control
In order to make all the desired functions work, the control system is required to receive data stably and effectively. Meanwhile, the size of the whole control system shall be small enough to be integrated into the umbrella structure.
Approach: The Raspberry Pi Zero would be an ideal control board to handle the multiple functions of the umbrella. The DTH22 is directly compatible with the Pi zero, it only requires some libraries to be installed.
Cooling system
There is a rigid demand that the device shall be integrated with a cooling system. The design of the cooling system needs to meet the required temperature range that the customer specified.
Approach: The material of the umbrella cover will have reasonable defensibility of heat and ultraviolet rays. Two or more mini humidifiers will be integrated into the umbrella to spray a mist to reduce the surrounding temperature. There are two potential pumps to use. The Anself can pump 240 L/H and the Vipe can do 120 L/H. The Anself is the bigger and more powerful pump, but reviews state that it is notorious for burning out if it is run dry. The Vibe is reviewed much more highly but it’s a weaker pump. We will be choosing the Vipe because it costs less and reviews state that it is more reliable.
Umbrella construction
The whole umbrella will be highly integrated. The factors of weight, size, and durability need to be considered.
Approach:
The whole umbrella will be highly integrated. The factors of weight, size and durability need to be considered.
Approach: The umbrella will use bubble style, which has about 51” canopy size and manual opening. The advantage of the bubble umbrella is that it can cover the upper body more effectively than the regular one. What’s more, the bubble umbrella would be the best shape during the windy conditions. The shape is considered a reasonable solution to make the inner area of the umbrella stable. The bubble shape ensures the mist spray naturally down. We will use 3D printing to build some of the structures as well as housing for the electrical components. The filament of the 3D printer has extrusion temperature from 356F to 210F. The PCB design may be also applied because we will have to design a waterproof housing for it.
Power supply
The user-specified that a solar panel is implemented into the design.
Approach: The solar panel that will be used is the uxcell 5Pcs 5V 60mA Poly Mini Solar Cell. It delivers enough power to charge the battery as well as power the circuit. When there is enough voltage coming from the solar panel, it will be used to power the umbrella. If not, the Samsung 20S 18650 2000mAh 30A Battery will be used to power the umbrella. The excess voltage from the solar panel will be used to charge the battery. There will be a diode circuit which compares voltage coming from the battery and the solar panels. Whichever is delivering more voltage will be the one used at that moment to power the umbrella.
Ultrasonic humidifier
The user-specified a humidifier in order to aide them with breathing properly outside.
Approach: The humidifier type that will be incorporated is an ultrasonic humidifier, in particular, the 20mm transducer fogger ceramics discs humidifier. There will be four separate humidifiers placed on the umbrella ribs, on opposite sides of each other. Since the humidifiers are spread out there will be ample surface area coverage to aid the users breathing. They will be controlled from the Raspberry Pi and will be adjusted based on the humidifier sensor reading. A single humidifier operates on 5V 300mA, which will be obtained from solar power supply or the backup battery.
Integrated fan
The user required the humidifier umbrella to lower the temperature. We choose to use an integrated fan to accelerate evaporation and thus cool the air temperature.
Approach: An integrated fan with a foldable propeller will be placed at the upper part of the umbrella. The propeller will be folded when the motor is off, and the umbrella is folded. This type of propeller shall be made using a 3D printer. For the motor of the fan, we choose a 1.5V to 3V DC motor. This motor runs at a continuous current of 0.09 A, consuming power as low as 0.135 W. Also, its size is small enough to fit in the umbrella rod, with a length of 17mm, a width of 9mm, and a thickness of 7mm.