Thermometer

This project uses an Adafruit DHT22 and a 4 row HD44780 LCD-Display to turn your Raspberry Pi into a thermometer that tracks the temperature and humidity.

Preferences

  • Raspberry Pi Model B
  • Adafruit DHT22
  • HD44780 4x20 LCD-Display
  • Python 2.7 at your Raspberry Pi

RPi and display

The following Pins on your RPi are used:

piPin

Pin Usage
1 Power DHT22 and LED +
2 Power HD44780
6 Common Ground (GND)
7 Data from DHT22
12 DATA7
16 DATA6
18 DATA5
22 DATA4
24 E
26 RS

It is recommended to use a breadboard.

The HD44780:

hd44780Pin

Connect the pins as shown in the graphic. You can use an additional 10K resistor at ‘Contrast’. The LED + could be connected to 5V but in my case it was to bright.

DHT22 soldering

If you have an Adafruit DHT22 without preinstalled resistor, use the following soldering instructions else ignore the soldering and just connect it (Pin 3 is GND then):

DHT22

You have four pins at the DHT22.

Pin DHT22 Description
1 3.3 Volt
2 Data
3 not needed
4 GND

You have to solder (or wire on your breadboard) an additional 10k resistor from positive voltage to the wire coming from the data pin.

Features

  • Auto setup (if needed)
  • Collect sensordata
  • Print data on display (time, temperature, humidity)
  • Reusable class for display
  • Hardwareinstructions
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