Voltage Regulator

To use the ESP8266 and the PPD42NS together we need 5V and 3.3V.

There are some ways to achieve this.

First option

Buy a LM1117.

Second option

I didn't have a LM1117, but got a LM317 and two resistors.

The schema to build a voltage regulator with this is:

schema

The source of the image is in https://github.com/opendata-stuttgart/sensors-software/blob/master/schematics/voltage-divider.fzz

Important: The LM317 pins are not as expected! The ADJ is the left pin. For reference see: http://www.st.com/web/en/resource/technical/document/datasheet/CD00000455.pdf

Test the voltage

Using the Arduino it's really easy to measure the voltage. The program is:

void setup() {
  Serial.begin(9600);
}

void loop() {
  Serial.println(analogRead(A0) * (5.0 / 1023.0));
  delay(1000);
}

The resulting voltage should be around 3.16V.

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