Published November 14, 2020 © MIT

Rice University ENGI 301 Project 1: IcyHot

Two-zone fan-thermometer system that records ambient temperature and displays it on a LCD screen powered by a Pocketbeagle

IntermediateWork in progress5 hours451

Rice University ENGI 301 Project 1: IcyHot

Things used in this project

Hardware components

Noctua NF-A4x20 5V PWM, Premium Quiet Fan, 4-Pin, 5V Version (40x20mm, Brown)

Adafruit 2.8" Color TFT LCD display

Adafruit Si7021 Temperature + Humidity Sensor

Jumper wires (generic)

Breadboard (generic)

Solderless Breadboard Half Size

BeagleBoard.org PocketBeagle

Hand tools and fabrication machines

Soldering iron (generic)

Story

About

The main goal of the project was to create a way to check the temperature of an ambient environment, display that information, and find a way to reduce that temperature. Currently, I live in a poorly ventilated dorm room where I often get stuffy. Checking my phone for the temperature is not helpful since the data is shows is collected from the temperature outside, rather than inside. I would like to know the temperature in my room so that I could know whether it would be worth it to open the windows, especially when I am laying in bed. Finally, what good is knowing the temperature and not being able to do anything about it? Not to mention this project is associated with a class I am taking so I might as well.

My vision for the project was a completely independent device that does not need internet connection to operate. I am on my computer often enough in my room, that is to say almost all the time, such that I would not mind connecting it to a computer. I would like the project to operate in the following manner: turn on the device by pushing a button already present on the PocketBeagle

I chose to use the PocketBeagle because it was the only available microcontroller I had and because it satisfies all of my project's requirements. Next, I searched for a fan that could operate with a 5 Volt input. This was difficult since I found that many computer fans operate with a 12 Volt input, which would ruin my PocketBeagle if I used it. Ultimately, I found a fan that met my needs, the Noctua NF-A4x20 5V PWM, Premium Quiet Fan, 4-Pin.

Next, I looked for a sensor that could measure temperature. For simplicity, I chose to use a digital sensor that could operate between 3.3-5 Volts since the PocketBeagle has was the most readily available micro-controller to me and it could satisfy all the requirements of my project. After some searching, during which I found many different analog sensors, I found the Adafruit Si7021 Temperature & Humidity sensor. Though it does a little more than what I need it to do, it meets my technical requirements while still being easy to operate. It also operates at 3.3V, great for the PocketBeagle!

The last piece of hardware that I specifically needed to buy that I could not find around the Oshman Engineering Design Kitchen (OEDK), Rice University's maker space, was a screen that could display the ambient temperature. I did not really have many requirements for this aside from that it needed to be able to display text. I was able to find such a screen in the 2.8" TFT LCF w/Touchscreen, also produced by Adafruit. It is also quite large so I would be able to see its output while normally sitting. As someone who wears glasses, this is very useful! My other components were simply breadboards and jumper cables that I found around the OEDK and/or were provided by my professor.

Wiring

My next step was to determine the proper pin placements to wire the entire device together. Fortunately, I was able to soldering the pins onto my PocketBeagle correctly about a month beforehand, so physically connecting the PocketBeagle to my first breadboard was not difficult. The difficult part was figuring out where each of the jumper wires were supposed to go with regards to the hardware and on what pin they went. I am very fortunate to have had the help of my professor, Erik Welsh, when doing the necessary wiring. For more details on the pin orientation, please see the information directly below.

Fan 1Connections:

PWM -> P1_36

TACH -> P1_33

GND -> P1_22

VOUT -> P1_24

Fan 2Connections:

PWM -> P2_1

TACH -> P2_4

GND -> P2_15

VOUT -> P2_13

Temperature & Humidity Sensor1Connections:

GND -> GND

VIN -> 3.3V

SCL -> P1_28

SDA -> P1_26

Note: 1k Ohm pull up to 3.3V for SCL

Note: 1k Ohm pull up to 3.3V for SDA

Temperature & Humidity Sensor1Connections:

GND -> GND

VIN -> 3.3V

SCL -> P2_9

SDA -> P2_11

Note: 1k Ohm pull up to 3.3V for SCL

Note: 1k Ohm pull up to 3.3V for SDA

LCD Display Connections:

CLK -> P1_8

MISO -> P1_10

MOSI -> P1_12

CS -> P1_6

D/C -> P1_4

Note: Circuit is completed by GND --> P1_16 and VOUT --> P1_14

Both temperature and humidity sensors were attached to separate, smaller breadboards due to space restrictions in the main breadboard.

Some pictures of wiring as follows:

Coding

Once everything was wired, I began to write my code. I wrote it right on the PocketBeagle in Cloud9. To operate the temperature sensor, I had to download one library, listed below:

Adafruit Si7021: https://github.com/adafruit/Adafruit_CircuitPython_SI702

First, the PocketBeagle must be connected to the internet so it can download several additional libraries on its own, which will take about 15 minutes in total.

For coding, I chose to use Python because that was the language that Adafruit offered the most support in for its libraries. I began by coding the fan. Fortunately, I did not need to download any specific libraries in order to get the fan's hardware to operate properly. However, I do need to be able to import Adafruit_BBIO.[pin type] for both GPIO and PWM pins, since the fan is a PWM fan. Afterwards, I began to attempt to code the temperature sensors. It was tough trying to figure out how to code for the pins to specifically use the I2C protocol, but that is all that is needed to code for the temperature/humidity sensor. Finally, I needed to code for the LCD screen. By following the tutorial provided by Adafruit, I was able to get text to show up once. However, I have not been able to replicate this in the timespan of this project.

Ultimately, I will acknowledge that I was unable to get the code fully completed in time, though I have been working on it since not only for personal development, but because I want to see this project to completion.

Video

The video only shows the component(s) that were successfully coded.

Dedications

Erik Welsh, my professor, for provided a ton of guidance throughout this project and helping me scope it out properly

Future Goals

Better integrate system as a whole
Integrate the LCD screen into the system

Code

IcyHot Code

""""
#!/bin/bash
# --------------------------------------------------------------------------
# IcyHot- Fan and Thermometer System
# --------------------------------------------------------------------------
# License:   
# Copyright 2020 Brian Dinh
# 
# Redistribution and use in source and binary forms, with or without 
# modification, are permitted provided that the following conditions are met:
# 
# 1. Redistributions of source code must retain the above copyright notice, this 
# list of conditions and the following disclaimer.
# 
# 2. Redistributions in binary form must reproduce the above copyright notice, 
# this list of conditions and the following disclaimer in the documentation 
# and/or other materials provided with the distribution.
# 
# 3. Neither the name of the copyright holder nor the names of its contributors 
# may be used to endorse or promote products derived from this software without 
# specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE 
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# --------------------------------------------------------------------------

Use the PocketBeagle to program a fan-temperature sensor apparatus consisting
of 2 fans, 1 thermal sensor, and 1 screen to display the local temperature.

**Screen not coded properly as of 11-13-20 at 11:59 PM CT. I'm currently working
on that as quickly as possible**

Requirements:
  -  Internet connection
  -  PocketBeagle
  -  iii

Uses:
  - 2 NF-A4x20 5V PWM 40x20mm PREMIUM FAN
  - Adafruit Si7021 Tempreature & Humidity Sensor
  - 2.8" TFT LCD w/Touchscreen
  - Libraries below:
    - Adafruit CircuitPython SI7021
    - Adafruit PIL
  
Attribution:
  - Github user enwi for their code fan_control.py, which controls fan speed
  - Professor Erik Welsh for walking me through how to navigate these libraries
  - Two fellow mechanical engineering students at Rice- Odnan Galvin and
    Nicholas Lester- who had previously taken ENGI 301, for explaining extra 
    software concepts
"""
"""
Temperature Sensors
"""
import time
import board
import busio
from busio import I2C
from board import SCL, SDA
import adafruit_si7021


# Create library object using our Bus I2C port
config-pin P1_28 i2c
config-pin P1_26 i2c
i2c = busio.I2C("P1_28", "P1_26")
sensor = adafruit_si7021.SI7021(i2c)


while True:
    print("\nTemperature: %0.1f C" % sensor.temperature)
    print("Humidity: %0.1f %%" % sensor.relative_humidity)
  time.sleep(2)



"""
Fans
"""
import Adafruit_BBIO.GPIO as GPIO
import Adafruit_BBIO.PWM as PWM
import os
import signal
import time


# For fan 1:
c_FAN_1 = "P2_1"					# pwm pin fan 1 is connected to
c_FAN_TACHO_1	= "P2_4"			# gpio pin fan 1's tachometer is connected to
c_MIN_TEMPERATURE_1 = 0		# temperature in degrees c when fan 1 should turn on
c_TEMPERATURE_OFFSET_1 = 2	# temperarute offset in degrees c when fan 1 should turn off

# For fan 2:
c_FAN_2 = "P1_36"					# pwm pin fan 2 is connected to
c_FAN_TACHO_2	= "P1_33"			# gpio pin fan 2's tachometer is connected to
c_MIN_TEMPERATURE_2 = 0		# temperature in degrees c when fan should turn on
c_TEMPERATURE_OFFSET_2 = 2	# temperarute offset in degrees c when fan should turn off

# Advanced configuration
c_PWM_FREQUENCY = 20		# frequency of the pwm signal to control the fan with
c_PWM_POL = 0    # polarity of the pwm signal 0

GPIO.setup("P2_4", GPIO.IN)
GPIO.setup("P1_33", GPIO.IN)
PWM.start("P2_1", 80, c_PWM_FREQUENCY, c_PWM_POL) # starts fan 1
PWM.start("P1_36", 80, c_PWM_FREQUENCY, c_PWM_POL) # starts fan 2

# Clean up GPIOs
GPIO.cleanup()

# Stop fans
PWM.stop("P2_1")
PWM.stop("P1_36")
PWM.cleanup()

"""
LCD SCREEN
"""
import digitalio
import board
from PIL import Image, ImageDraw
import adafruit_rgb_display.ili9341 as ili9341

# Initial setup
BORDER = 20
FONTSIZE = 24
spi = board.SPI()
cs_pin = 'P1_06'
dc_pin = "P1_04"
BAUDRATE = 24000000
disp = ili9341.ILI9341(
    spi,
    rotation=90,  # 2.2", 2.4", 2.8", 3.2" ILI9341
    cs=cs_pin,
    dc=dc_pin,
    baudrate=BAUDRATE)
# pylint: enable=line-too-long

# Create blank image for drawing.
# Make sure to create image with mode 'RGB' for full color.
if disp.rotation % 180 == 90:
    height = disp.width  # we swap height/width to rotate it to landscape!
    width = disp.height
else:
    width = disp.width  # we swap height/width to rotate it to landscape!
    height = disp.height
image = Image.new("RGB", (width, height))
 
# Get drawing object to draw on image.
draw = ImageDraw.Draw(image)
 
# Load a TTF Font
font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", FONTSIZE)
 
# Draw Some Text
text = "Hello World!"
(font_width, font_height) = font.getsize(text)
draw.text(
    (width // 2 - font_width // 2, height // 2 - font_height // 2),
    text,
    font=font,
    fill=(255, 255, 0),
)
 
# Display image.
disp.image(image)

Credits

Brian Dinh

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Rice University ENGI 301 Project 1: IcyHot

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

About

Wiring

Coding

Video

Dedications

Future Goals

Schematics

System Block Diagram

Power Block Diagram

Code

IcyHot Code

Credits

Brian Dinh

Comments

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Rice University ENGI 301 Project 1: IcyHot

Rice University ENGI 301 Project 1: IcyHot

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

About

Wiring

Coding

Video

Dedications

Future Goals

Schematics

System Block Diagram

Power Block Diagram

Code

IcyHot Code

Credits

Brian Dinh

Comments

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