Make the Gadget

This build has several finicky steps. Look at the breadboard view (Figure 7-2) to see how it all fits together.

Parts

  1. Arduino
  2. Ethernet shield
  3. Breadboard
  4. DHT-22 sensor
  5. 4Char display
  6. 4.7K resistor
  7. Red and black jumper wires

Breadboard the Circuit

Step 1 Power the breadboard rails.

Step 2 Connect a red jumper wire from the 3.3v pin on the Arduino to the voltage (red) rail on the breadboard, and a black jumper from the GND pin to the ground (black) rail on the breadboard.

Step 3 Connect a short red jumper from the voltage rail to the voltage (leftmost) pin of the DHT-22 temperature and humidity sensor.

Step 4 Connect a short black jumper from the GND rail to the GND (rightmost) pin of the DHT-22.

Step 5 Connect a green jumper from the DATA (second from the left) pin on the sensor to digital pin 4 on the Arduino.

Step 6 Add a 4.7K resistor between the DATA pin of the sensor and the VOLTAGE pin.

Step 7 Connect a green jumper from Arduino pin 3 to the RX (rightmost) pin of the four-character display, and a black jumper from the GND rail to the GND (leftmost) pin of the four-character display.

The completed circuit for the temperature-humidity-dew point monitor.

Figure 7-2. The completed circuit for the temperature-humidity-dew point monitor.

Write the Code

Load the following sketch onto Arduino. You can find it at EMWA GitHub repository | chapter-7 | TempHumidDewpoint.

/* Temperature-Humidity-Dew Point Monitor This sketch gathers temperature and ...

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