Template: RPi Zero Relay Guide

Install Library

If you use the bookworm system, you can only use lgpio library, bcm2835 and wiringPi can't be installed and used.

BCM2835

#Open the Raspberry Pi terminal and run the following command
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.71.tar.gz
tar zxvf bcm2835-1.71.tar.gz 
cd bcm2835-1.71/
sudo ./configure && sudo make && sudo make check && sudo make install
# For more, you can refer to the official website at: http://www.airspayce.com/mikem/bcm2835/

WiringPi

#Open the Raspberry Pi terminal and run the following command
cd
sudo apt-get install wiringpi
#For Raspberry Pi systems after May 2019 (earlier than that can be executed without), an upgrade may be required:
wget https://project-downloads.drogon.net/wiringpi-latest.deb
sudo dpkg -i wiringpi-latest.deb
gpio -v
# Run gpio -v and version 2.52 will appear, if it doesn't it means there was an installation error

# Bullseye branch system using the following command:
git clone https://github.com/WiringPi/WiringPi
cd WiringPi
. /build
gpio -v
# Run gpio -v and version 2.70 will appear, if it doesn't it means there was an installation error

lgpio

#Open the Raspberry Pi terminal and run the following command
wget https://github.com/joan2937/lg/archive/master.zip
unzip master.zip
cd lg-master
sudo make install

# You can refer to the official website for more: https://github.com/gpiozero/lg

• Python

sudo apt-get update
sudo apt-get install python-serial
sudo pip install python-can

Download Examples

Open a terminal and run the following commands to download the demo codes:

sudo apt-get install p7zip-full
wget https://files.waveshare.com/upload/2/2f/RPi_Zero_Relay_Code.7z
7z x RPi_Zero_Relay_Code.7z  -r -o./RPi_Zero_Relay_Code
sudo chmod 777 -R RPi_Zero_Relay_Code/

CAN Bus

The sample demo uses two RPi-Zero-Relay modules. Python and C language demos are provided.

Configuration

• Modify the config.txt file:

sudo nano /boot/config.txt

Add the following lines to the config.txt file and save:

dtparam=spi=on
dtoverlay=mcp2515-can0,oscillator=16000000,interrupt=25,spimaxfrequency=3000000

• Reboot.

sudo reboot

• Check if the driver is initialized normally.

dmesg | grep -i '\(can\|spi\)'

The result should be like the picture:

If the MCP2515 driver is not initialized normally you need to reboot and check if the devices are connected properly (H to H and L to L).

C Examples

• Run the receive example:

cd ~/RPi_Zero_Relay_Code/CAN/wiringPi/receive/
make clean
make
sudo ./can_receive

After running the received code, the terminal is waiting for data.

• Run the Send examples:

cd RPi_Zero_Relay_Code/CAN/wiringPi/send/
make clean
make
sudo ./can_send

Type data to send.

In the receiving terminal, you will get the packet related to the id.

Python examples

• Open a terminal and run the commands:

cd RPi_Zero_Relay_Code/CAN/python/
#For receiving：
sudo python can_reveive.py
#For sending:
sudo python can_send.py

Connect to other CAN device

If you need to connect the RPi Zero Relay to other CAN devices, please note that:

• Please check the connection, it should be H to H and L to L.
• Make sure that the baud rate of both sides is the same, the default baud rate of examples is 100K.
• Check if the CAN ID of both sides is the same.
• If data is always lost while transmitting, please decrease the baud rate and test it again.

RS485 Interface

The sample demo uses two RPi-Zero-Relay modules. Python and C language demos are provided.

Configuration

• Open a terminal and run the command.

sudo raspi-config

Choose Interfacing Options -> Serial -> No -> Yes.

Disable the login shell function and enable the hardware serial port.

• Reboot

sudo reboot

• Connect the device, A to A and B to B.

C examples

• Run the receive example:

cd RPi_Zero_Relay_Code/485/WiringPi/send
make clean
make
sudo ./485_receive

After running the received code, the terminal is waiting for data.

• Run the Send example:

cd RPi_Zero_Relay_Code/485/WiringPi/send
make clean
make
sudo ./485_send

• Input data and send:

• The receiving terminal receives and prints:

Python examples

Open a terminal and run the commands:

cd RPi_Zero_Relay_Code/485/python/
#Receive example：
sudo python receive.py
#Send example：
sudo python send.py

Troubleshooting

If the RS485 cannot work normally, please check:

• Please check if you have disabled the login shell function.
• Please check the connection, it should be A to A and B to B.
• Please test with USB to RS485, and make sure that all the settings are correct.