Input device :

Let's interface it!

Assignment for this week

• Measure something: add a sensor to a microcontroller board that you have designed and read it
• Link to this week’s home work page

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What I have done?

Updated

That board is the one I will use for my greenhouse (final project) so I can finished this assigment and goind forward for my final project

Sensors

For this week, we wil focus on input devices. That's good because I need them for my final project!

I will use 2 sensors :

• DHT11 basic temperature-humidity sensor
• Photosenitive Sensor Module

With the two of them I can get the temperature, humidity and a basic idea of the luminosity. Not a bad start!

Updated

DHT11 basic temperature-humidity sensor

Here are the ranges and accuracy of the DHT11 and it's datasheet:

• Humidity Range: 20-90% RH
• Humidity Accuracy: ±5% RH
• Temperature Range: 0-50 °C
• Temperature Accuracy: ±2% °C
• Operating Voltage: 3V to 5.5V

the connection is quite easy, the DHT11 has only 3 pin (this model has the 10k resistor already included in his package) : GNF, VCC and Signal.

the connection is quite easy, the DHT11 has only 3 pin (this model has the 10k pull-up resistor already included in his package) : GNF, VCC and Signal.

In order to read something from it, I will use IDE Arduino

I will need first to add the DHT library to my IDE

                                    
                                      #include <dht.h>
                                      dht DHT;

                                      #define DHT11_PIN 7

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

                                      void loop()
                                      {
                                        int chk = DHT.read11(DHT11_PIN);
                                        Serial.print("Temperature = ");
                                        Serial.println(DHT.temperature);
                                        Serial.print("Humidity = ");
                                        Serial.println(DHT.humidity);
                                        delay(1000);
                                      }
                                    
                                  

Photosensitive Sensor Module

An LDR is a component that has a (variable) resistance that changes with the light intensity that falls upon it. This allows them to be used in light sensing circuits.

Here I will simply use it to read the level of luminosity from the ldr (a value between 0-1023)

Updated

I have redo the excercise with my final board and everything went fine. I have simply connect my sensors to the board and read the value again, picture below

                                    
                                      int LDR = A0;            // LDR input at A0 pin
                                      int LDRReading = 0;      // to store input value of LDR


                                      void setup() {
                                        // put your setup code here, to run once:
                                      Serial.begin(9600);

                                      }

                                      void loop() {
                                        // put your main code here, to run repeatedly:
                                      LDRReading = analogRead(LDR);
                                      Serial.println(LDRReading);
                                      delay (3000);
}
                                    
                                  

Updated

Summary :
This assignment was really nice and that was even better that my board works in the first try. Looking good for the final project!

Date: March 2017