Rapsberry Zero 2W – BME68x – DS18B20 – ILI9341 TFT hardware setup

Part 2: hardware list, setup and wiring

I’m commencing this brief tutorial with my Raspberry Pi Zero 2W featuring the ili9341 2.8-inch TFT screen, as it’s one of the most widely used displays available. I’ve incorporated a Waveshare BME68x sensor for inside temperature, air pressure, and humidity readings, complemented by an external DS18B20 sensor with an extension cable housed in a waterproof casing.

Here are the hardware components I acquired for this project:

Optional components:

1. Start by soldering on the GPIO header for convenient plugging and replugging of all sensors. Note that there are plans to sell Raspberry Pi Zero 2 WH (with an added H for header) that come pre-equipped with a GPIO header, eliminating the need for soldering. However, I couldn’t find those, so I opted for this model without a header. This should give you the following wiring plan:

Rapsberry Zero 2W with soldered GPIO header

2. Optionally equip your Raspberry Pi Zero 2W with a cooler, especially if it might be exposed to direct sunlight, needs to endure summer months, or has a considerable workload depending on other services running on it. With only temperature readouts, screen image views, and database services, my Raspberry stays quite cool, ranging between 30 and 35 degrees Celsius. However, one of my Raspberries also has a webcam (camera module 3) since I plan to use it as a UVC webcam. When the video streaming service is active, it easily reaches the 65-degree range quickly. You can also use the video streaming service as a webcam outside your cabin or holiday home, depending on where you place the climate control system.

3. Connect the Bosch BME68x sensor to it. I use a BME680 and a BME688 on the two Raspberries, although this doesn’t make any difference for this project. The 688 version includes optional AI support, but that requires additional proprietary code from Bosch, which I haven’t installed on my setup yet. My code works the same for either the BME680 or the BME688 variant.

Official Rapsberry Pi Zero 2W Pinout and hardware documentation

Here you will find the hardware pinout drawing of all the GPIO header pins on your little Raspberry. Open this page for double checking 🙂

BME68x wiring:

  • In I2C mode:
VCC3.3/5 Voltsphysical pin 1 (red cable)
GNDGround physical pin 6 (black cable)
SDASDA1physical pin 4 (blue cable)
SCLSCKphysical pin 5 (yellow cable)
BME68x I”C wiring

The ADDR/MISO and CS connectors are not used in this setup. Avoid touching the sensor during installation, as the components are sensitive and may provide inaccurate values if not treated carefully.

Waveshare BOSCH BME688 sensor

4. Connect the DS18B20 outside temperature sensor using the 1-wire bus system of the Raspberry. This sensor only uses one data line into the Raspberry, so it only has three cables, as you also need VCC (power 3.3 or 5 Volts) and GND (grounding).

DS18B20 wiring:

VCC3.3/5 Voltsphysical pin 2 (orange cable)
GNDGroundphysical pin 9 (green cable)
DQ PinData physical pin 18 (GPIO 24) (yellow cable)
DS18B20 1-wire bus wiring
Waterproof housing of the DS18B20 outside tempterature sensor
Terminal connector for the DS18B20 with included resistor between DAT and VCC

5. Connect the 2.8-inch ILI9341 display to the Raspberry’s GPIO header. Since I opted not to run in text mode and used generated pictures for presentation, I set up the display as the default system display capable of running a graphical desktop manager—a so-called framebuffer device. This is a different setup that I’ll describe in another tutorial with my Raspberry Pi Zero 2 that has the ST7789V controlled display. Using a framebuffer display eliminates the need for additional drivers or code to display images in a slideshow on the screen. It’s quite easy to use the “fbi” program (framebuffer image viewer) on Linux to generate a slideshow here. A small drawback: fbi doesn’t allow some cool fade-in or fade-out effects for the slideshow, which I have on the other Raspberries. I’ll still attempt to create the fade effect using the display PWM dimming to black, but that is a later project not covered here.

Let’s wire the screen:

DisplayRPi PinGPIO
VCC173.3 Volt
ILI9341 wiring
2,8 inch TFT display cabling

With all these accessoires, the Raspberry GPIO header is quite filled already. Now, the hardware is set up and ready to be activated by software. Continue to the next part that covers Operating System installation, hardware and driver configuration, and software for our climate project.

Part 3: You can now continue to the OS and software setup to read out your temperature sensors and store the values in a MySQL database.