Table of contents

RoadTest: Raspberry Pi 3 Model A+

Author: meera_hussien

Creation date: 4 Jul 2019

Evaluation Type: Development Boards & Tools

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: The other parts which are comparable to this product would be the other manufacturer of this similar product such as the banana pi and orange pi

What were the biggest problems encountered?: There were no such big problems encountered. There are a few challenges which I face during the review. On the hardware, it was as good but coming to the software part I face some difficulties in getting a working library for my simple project.

Detailed Review:

Review On Raspberry Pi 3 A+

1. Introduction

2. Product Details

3. Getting Started

4. Simple Project

5. Conclusion

1. Introduction

My review today is about the Raspberry Pi 3 A+ which was the last product under Raspberry Pi 3 category. It was launched on the last quarter of 2018. To know more about the history of the PI boards you may click this link. This model comes in a smaller size. The size is between the Raspberry Pi 3 and Raspberry Pi zero. In the first part, we shall look into the details of the board. and followed by the performance of the board. Next, we shall look into a simple project using the raspberry pi board and lastly on the conclusion.

Below is the image of the Raspberry Pi3 A+

Next, we shall see the details of the board.

2. Product Details

Below is the specification of the board.

The board details are as shown below

Below is the physical drawing of the raspberry pi.

3. Getting Started

Before we can start to test the raspberry, we need a few things ready. We will need a power supply with a rating of 5V 2500mA. And the next thing which we will need is the Sd card with the installed OS. Since this module cannot be connected through a terminal we need to prepare the other PC accessories such as the PC and other computer accessories. The OS which I use is the Raspbian. For formatting the sd card I have use SD Formatter. And to flash the Raspbian OS to the sd card I have use Etcher. Both of this are free so please feel free to use them. Once the sd card is ready, put it in the sd card slot and powered it up.

Upon powering it, we need to get the latest update. To do that we can use the below code

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sudo apt-get update

The next we want to do is to check the spec of the board. This can be accomplished using the code below

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lscpu

This is the spec of the board.

Next, we install the sysbench. this can be done using the code below

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sudo apt-get install sysbench  

The reason why we are installing the sysbench is to monitor the performance of the raspberry pi device. There are a few tests which we can execute.

1. CPU test

2. Memory

To know the details of the pinout of the board, we can get it by simply keying in "pinout"

4.Simple Project

For this simple project, I have decided to make the IoT system. Basically what the system does is it measures the temperature and humidity, and send the data to the internet through wifi. To achieve the objective of this project I have used

• Raspberry Pi 3 A+
• DHT11
• i2C 16x2 LCD

And for the monitoring purpose, I have to use the "Thingspeak".

Once we have all the items ready we can start to build our project. The circuit for the project is as shown below

Once we have made the connection as per the image above. We can start to code. The first thing we want to do is to enable the i2C connection. This can be done by following the steps below

First, go to Raspi-Config

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sudo raspi-config

Go to Interfacing Options

And go to I2C

And finally, click on the I2C and choose to enable

The next step is to install the necessary library, which is the I2C-tools and the SMBUS. To do this follow the step below

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sudo apt-get install i2c-tools.

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sudo apt-get install python-smbus

Once we are finished with the installation, we need to restart the PI and log in again. Once we are done with this we can check the address for our LCD. To do this type

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i2cdetect -y 1

We can see from the image below that, that LCD address is 27. Just keep the number, in case we need them. A detailed tutorial on how to set up the LCD can be found here

.The next library which we need to install is the dht11. For this project, I have decided to use the adafruit library. Type the code below in the terminal

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pip3 install adafruit-circuitpython-dht

Now the python environment is ready for our coding purpose. Next, we need to create a thingspeak account. Once we have successfully created the account, we need to configure our channel. To do that go to the API Keys to get the key number. As shown in the video below

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This unique API key needs to be captured in our code.

The full code is as shown below

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import time
import board
import I2C_LCD_driver
import adafruit_dht
import sys
import requests#initial  the dht device, with data pin connected to:
dhtDevice = adafruit_dht.DHT11(board.D4)

#initial the lcd
mylcd = I2C_LCD_driver.lcd()


#Enter Your API Code Here
myAPI = 'KCDSWNQ9ELK6XEWR'
# URL where we will send the data, Don't change it
baseURL = 'https://api.thingspeak.com/update'
mylcd.lcd_display_string("Temp & Humidity", 1)
mylcd.lcd_display_string("  Monitoring Sys", 2)
time.sleep(3.0)



while True:
     try:
          #print the values to the serial port          
          temperature_c = dhtDevice.temperature
          temperature_f = temperature_c * (9 / 5) + 32          
          humidity = dhtDevice.humidity
          print("Temp: {:.1f} F / {:.1f} C   Humidity: {}%".format(temperature_f, temperature_c, humidity))

          mylcd.lcd_clear()
          mylcd.lcd_display_string("Temp: %d%s C" % (temperature_c, chr(223)),1)
          mylcd.lcd_display_string("Humidity: %d %%" % humidity,2)
          
          data = {'api_key': myAPI, 'field1':temperature_c, 'field2':humidity};
          result = requests.post(baseURL, params=data)
          print (result.status_code)
                if result.status_code == 200:
                    print ("Success!! Thingspeak")
                else                    
                    print ("Fail!! Thingspeak")       
          
                       
     except RuntimeError as error:
          #Errors happen fairly often, DHT's are hard to read, just keep going          
          print(error.args[0])
        
     time.sleep(2.0)

Below are the images of the setup for the project.

DHT11 Sensor

The output:

Meanwhile, the same data is captured in the thingspeak

The data in the thingspeak can be processed to do many other calculations such as getting the average below or transfer the value to an excel sheet. That's about the simple project using the Raspberry Pi3 A+ model.

5. Conclusion

The prementionaed board is a good developed board for a new user who wishes to learn about python and use it as a processor for an electronics project due to itd simplisity and minitrized size. In comparision with the Raspberry Pi Zero, it offer standard HDMI and USB 2.0 port . In addition, Raspberry Pi A+ would be more prefered among the student and hobbyist.