We use an orangepi zero to poll and display cryptocurrency market info and weather forcase report from remote http server using wifi, and with help of a sht30 sensor adding to orangepi i2c driver, we can also get realtime temperature and humidity.
We have three destinations currently:
- Poll cryptocurrency market info from remote http server.
- Poll weather forcast report from remote http server.
- Use a sensor to capture local temperature and humidity in realtime.
- Orangepi zero development kit with ubuntu 20.04 system installed as a server.
- A 1.8 inch(resolution 128x160) LCD with st7735 driver.
- sht30 temperature and humidity sensor, we use GT-HT30 to replace it as their pins are compatible.
- Orangepi can access internet by wireless. if not, configure file /etc/network/interfaces as belows.
auto lo
iface eth0 inet dhcp
auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
gateway $your_router_ip
dns-nameservers $your_router_ip
wpa-ssid "your WIFI name"
wpa-psk $psk-info$psk-info can be generated by run cmd wpa_passphrase $wifi_name $wifi_password, if wpa_passphrase not installed, you can run sudo apt install wpasupplicant to install it.
- Enable SPI in linux kernel.
Edit /boot/orangepiEnv.txt to add line :overlays=spi-spidev param_spidev_spi_bus=1
Then reboot orangepi. if you see spi device like belows, means spi module has beein installed successfully.
root@orangepi:~# ls /dev/spi*
/dev/spidev1.0
Edit /boot/orangepiEnv.txt to add line :
overlays=spi-spidev
param_spidev_spi_bus=1- Enable I2C driver in linux kernel.
Edit /boot/orangepiEnv.txt to add line :
overlays=i2c0 i2c1
Then reboot orangepi. if you see i2c device like belows, means i2c module has beein installed successfully.
root@orangepi:~# ls /dev/i2c*
/dev/i2c-0 /dev/i2c-1
If you want to enable both i2c and spi, overlays can be set like belows:
root@orangepi:~# ls /dev/i2c*
overlays=spi-spidev i2c0 i2c1
sudo python3 -m pip install OPi.GPIO spidev Pillow numpy
sudo python3 -m pip install st7735If installing numpy has error, you can use following cmd:
apt-get install python3-numpy
2. As st7735 package only supports raspberry by default, We modify st7735 init.py code in pip packages to support orangepi.
import RPi.GPIO as GPIO -> import OPi.GPIO as GPIO| Screen Pin | Orange pi Pin |
|---|---|
| GND | Ground (pins 6, 9, 14, 20, 25, 30, 34 or 39) |
| VCC | 5v Power (pins 2 or 4) |
| SCL | GPIO 11 (pin 23) |
| SDA | GPIO 10 (pin 19) |
| RES | GPIO 25 (pin 22) |
| DC | GPIO 26 (pin 7) |
| CS | GPIO 8 (pin 24) |
| BL | Not connected |
If you want to your own defined pins, you can find all pins mapping gpio info here, if you do that, you also need to change st7735 GPIO number in the code.
python3 lcd_test.pyIf there are words displyed in LCD, congratulations! LCD has been installed successfully!
You can connect 4 pins of sht30 to i2c0 or i2c1. You can test and get i2c address by running:
i2cdetect -y 0
#or
i2cdetect -y 1
to test if i2c device has been configured successfully.
Connected lines are as belows:
We use smbbus to connect i2c device, so install it:
apt-get install python3-smbus
python3 sht30_test.py python3 orangepi-iot.py