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Hardware installation
Software installation
The PiTFT is easy to get and easy to run the pizero_bikecomputer program on X Window, so it's a good idea to start with this one.
- top left: PiTFT 2.4
- central left: Raspberry Pi Zero WH
- central right: GPS module
- bottom left: Enviro pHAT
- bottom right: ANT+ USB dongle and micro USB OTG Adapter
First of all, connect the Enviro pHAT without the header(I2C SDA, I2C SCL, 3.3V and GND).
Next, connect the PiTFT.
Connect the GPS module in the same way as the Enviro pHAT.
| Name | Raspberry Pi | GPS |
|---|---|---|
| UART TX | IO8 | RX |
| UART RX | IO10 | TX |
| GND | IO6 | GND |
| VCC | 5V or 3.3V | VIN(5V or 3.3V) |
Finally, fix each parts with screws. To prevent from being disconnected by vibration, fix the USB power cable and ANT+ USB dongle to the PiTFT board with the tape.
It is more reliable to solder the PiTFT directly to the header of Raspberry Pi Zero.
Follow official setup guide of Adafruit, or my setup guide (Japanese).
If you run the program in a console, you need to build Qt5 and PyQt5 because the package python3-pyqt5 provided with Raspbian OS does not include a touchscreen library(tslib).
Note:
The touchscreen does not work properly in Raspbian OS(Buster) + Qt 5.14(or higher) + PyQt 5.14(or higher) from some issues. So, if you use PiTFT, I recomand to run on X Window at present. In Raspbian OS(Stretch) + Qt 5.12.3 + PyQt 5.12.3, the touchscreen works.
Follow "Building Qt 5.12 LTS for Raspberry Pi on Raspbian" with Raspberry Pi 4 4GB or 8GB. Use the compile option "-platform linux-rpi-g++" for Raspberry Pi 1 or zero, not use options for Raspberry Pi 4 and so on. Use the same SD card on Raspberry Pi 4.
You will need libts-dev package before configure of Qt. (from RaspberryPi2EGLFS)
sudo apt-get install libudev-dev libinput-dev libts-dev libxcb-xinerama0-dev libxcb-xinerama0
Follow PyQt Reference Guide. The source is available here
$ cd
$ mkdir work; cd work
$ wget NEWEST-PYQT5-PACKAGE-SOURCE-FILE
$ sudo pip3 install PyQt-builder
$ sip-build --no-make --qmake PATH-TO-YOUR-QMAKE
$ cd build
$ make -j4
$ sudo make install
$ sudo pip3 install PyQt5-sip
If you run the program from the SSH login shell, add the following environment variable.
export DISPLAY=:0.0
Then, run the program.
$ python3 pizero_bikecomputer.py -f
Making launcher menu or desktop icon may be useful.
Make "New Item" in Main Menu Editor, and set "/home/pi/pizero_bikecomputer/exec.sh" in "Command:" field.
If you are using the autologin option, you can run the program automatically using the following procedure。
$ mkdir -p ~/.config/lxsession/LXDE-pi
$ cp /etc/xdg/lxsession/LXDE-pi/autostart ~/.config/lxsession/LXDE-pi/
$ echo "@/home/pi/pizero_bikecomputer/exec.sh" >> ~/.config/lxsession/LXDE-pi/autostart
Before run the program, add the following environment variables.
$ export QT_QPA_PLATFORM=linuxfb:fb=/dev/fb1
$ export QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS=/dev/input/event0:rotate=270
$ export QT_QPA_FB_TSLIB=1
$ export TSLIB_FBDEVICE=/dev/fb1
$ export TSLIB_TSDEVICE=/dev/input/event0
$ python3 pizero_bikecomputer.py
Note: Works with Raspbian Stretch. No further versions have been confirmed to work. It seems that the touch screen axis is not set.
From left to right, the button assignments are as follows.
| GPIO NUM | Short press | Long press |
|---|---|---|
| 5 | Left (<-) | None |
| 6 | Lap | Reset |
| 12 | Screen brightness On/Off | None |
| 13 | Start/Stop | None |
| 16 | Right (->) | Menu |
In the menu, the button has different assignments. From left to right, the button assignments are as follows.
| GPIO NUM | Short press | Long press |
|---|---|---|
| 5 | Back | None |
| 6 | None | None |
| 12 | Enter | None |
| 13 | Select items (Back) | None |
| 16 | Select items (Forward) | None |
Both short press and long press can be changed. And only the GPIO number of PiTFT 2.4 is supported. For other models, you need to change it in modules/config.py.