Raspberry Pi Embedded System Development Kit for Beginners

1. Introduction: Raspberry Pi Embedded System Development Kit
Raspberry Pi Embedded System Development Kit
is a perfect product for learning or using raspberry. Based on raspberry pi zero, it has a 320*240 LCD with a touch for display and integrates a chip to process audio playing & recording. It also has been equipped with a speaker, a 3.5mm audio jack and two mics, and some common add-on functions for Pi such as the A/D and GPIO expansions. It uses an SPI display and hardware expansions such as Mic/Audio, to make it more suitable for embedded projects.
As one of the most successful open hardware platforms, Raspberry Pi has been widely used in plenty of applications. This Pi interface Hat could be very suitable to learn Raspberry Pi for beginners.
Makerfabs
provided many demos for raspberry to display, play, record, and so on. These demos are available for you to study easily. So, lets begin with Raspberry Pi Embedded System Development Kit.
2. Features
Raspberry pi zero W, 1GHz single-core CPU, 512MB RAM, Micro USB OTG port, Mini HDMI port, CSI camera connector, wireless LAN, and Bluetooth
3.2inch display, 320×240, ili9341 driver with SPI
Resistive touch screen, XPT2046 controller
Speaker
3.5mm audio jack
Stereo Codec with Class D Speaker Driver: WM8960
MEMS Mic*2: AOS3729A-T42-NXC
Hardware expandable: I2C port, GPIO port, UART port
ADC port
：
ADS1115
Type-C USB power or battery power
Support chargeable and 1A Maximum charging current
Overcharge and over-discharge protection
Size: 94mm*80mm*24mm
3. Diagram & Parts Details
The board has 3.2 inch TFT LCD Display along with pair of mics on both sides.
On the left and right sides there are ports named port1, port2, port3, port4, port7, and port8. It includes Power Pins, GIPO Pins, Analog Pins & I2C Pins.
On the front side it has port5 and port6 as Power, GPIO & UART Pins. In order to power the board, a Type C USB port is available. There is a power button to turn ON the module.
A Raspberry Pi Zero W Board is embedded in the kit which has a 16GB SD Card Storage. For Audio Input 3.5mm Audio Jack is available and for audio output, a Speaker is embedded on the board. You can power the board using 3.7V Lithium-Ion Battery or by using a Type C USB Power Supply.
4. Basic Usage
Start by opening the package of the product, press the button, and Pi interface Hat can be used normally. As the system power-up (Pi Zero required about one minute to start), it will show a short animation with audio.
Next, there are three options that will be shown and can be pressed to run the different programs respectively, then you can try some of the basic demos: testing screen, recording audio, and measuring temperature.
Touch Set
Click the black pixel one by one on the screen with your finger or touch screen pen, it is to calibrate the touch accuracy. The screen will flash a new page that you can touch or draw at will. Press the button at the top right to back to the options menu.
Record audio
Click the recording button at the left to start record audio with a length of 5 seconds. Click the play button at the right, the speaker will play the audio recorded.
Measure temperature
Connect the Mabee_DHT11 module to the product Port 5 (GPIO 22), touch the measuring temperature button. The temperature and humidity will be display on the screen after a moment.
5. Connecting to Internet via WiFi
Before starting, you have to connect the raspberry to your WiFi.
Prepare a Software
A. SSH protocol
SSH or Secure Shell is a cryptographic network protocol for operating network services securely over an unsecured network. Typical applications include remote command-line, login, and remote command execution, but any network service can be secured with SSH.
B. PuTTY tool
PuTTY is an SSH client, usually used to remotely control the Raspberry Pi. You can get the install package from here:
https://www.putty.org/
How to connect?
Remove the SD card from the raspberry pi and insert the SD card into the PC. Enter the SD card root, you will see some files in the root.
Create a new file to this root with the name “
wpa_supplicant.conf
”.
Open the new file
wpa_supplicant.conf
with text, and copy the following code to it. Fill in your WiFi SSID and password into the code instead of “***”. Then save the file and exit.

Country
=
CN
ctrl_interface
=
DIR
=
/
var
/
run
/
wpa_supplicant
GROUP
=
netdev
update_config
=

network
=
{
ssid
=
”
*
*
*
*
*
”
psk
=
”
*
*
*
*
”
key_mgmt
=
WPA
PSK
priority
=

Set up a folder called SSH in the root, which is to turn on the Raspberry Pi SSH service.
Plug the SD card back into the Raspberry Pi, and power on the Pi Interface Hat again. Raspberry Pi will automatically connect to WIFI.
Make sure your computer and Raspberry Pi are on the same network. Open the Putty, enter “
raspberrypi.local
” in the address box, and click “
open
”.
Input the Raspberry Pi Username and password step by step.
Raspberry Pi Username:
pi
The initial password for Raspberry Pi:
raspberry
Note
: It will not be displayed when entering a password and you have to complete it in one time.
Now input the command “
ifconfig
” in the terminal to check the Raspberry Pi IP.
The WiFi connection is complete. You can use the IP to enter the Putty terminal next time, as follow.
6. Kill the process of default program.
Because of the default program (the 3 demos) started automatically, you have to kill the process to ensure the Pi is not in busy status, follow the steps to kill.
Enter the “
top
” command in the terminal, and find the id of the default program. In the top table, check the PID number which the COMMAND is “
default_demo
”, and the number is the process ID.
Click “Ctrl+C” to exit the top table.
Enter the below command to kill the process.

Sudo
kill

7. Projects with Raspberry Pi Embedded System Development Kit
For learning further, Makerfabs provided multiple examples to show how to use. In many examples, additional programs need to be used instead of just Raspberry commands.
For convenience, we have loaded the project to the Raspberry, and the next chapter will show how to use them. The project covers all the programs for the demo, and it is necessary to follow the step to use the program for success.
1. Recode and Play
Follow the steps to install the Linux kernel drivers for recording and playing (NOTE: If the Raspberry Pi OS is provided by Makerfabs, please ignore this step that the driver has been installed).
(
Optional
) Enter the following command in the Raspberry Pi terminal window to install the driver:

git
clone
https
:
//github.com/respeaker/seeed-voicecard
cd
seeed
voicecard
sudo
/
install
sh
sudo
reboot
Print the sound card list to see if the driver installation is successful.

Aplay
l
The “card 1” is the driver of the speakers and mics.
Use the “
alsamixer
” command to enter the Interface to adjust the sound card volume. Press the
F6
button to switch the sound card. As the figure, the “
x1
” is your sound card.
Use the following command for
voice recording
. At the end of the recording, Raspberry Pi gets a two-channel wav file. Sometimes you have to change the number in the text “
-Dhw:1,0
” to “
-Dhw:0,0
”, “
-Dhw:2,0
” or any.

Arecord
c

r
16000
f
S16_LE
Dhw
:

d

temp
wav
“
-Dhw:1,0
” means that sound card 1 is used for recording, “

” means that the recording time is 3s, and “
temp.wav
” is the file name which saved for recording.
Use the following command to play audio.

aplay
Dhw
:

temp
wav
“
-Dhw:1,0
” means that sound card 1 will be used for output, and “
temp.wav
” is the name of the output file.
Note1:
the sound card can only support audio WAV-formatted and two-channel.
Note2:
the volume is recommended to adjust to 80%, too strong is bad for playing. When it is powered by a battery, sometimes the unsteady voltage will cause the speaker to work not well.
2. Display picture
3.2 inch LCD wit