Introduction to Arduinos for Environmental Applications

First-year Physical Geography Taster Sessions Dr Thomas Smith

INTELLIGENT TWEETING SENSORS: INTRODUCING ARDUINO MICROCONTROLLERS

THE BASICS OF ARDUINO MICROCONTROLLERS

• Open source hardware

• Open source development kit

• User community driven

WHAT DO THEY DO?

• Digital I/O (LEDs, switches)

• Analogue I/O (resistive sensor data)

• Serial connection (sensors, GPS, etc.)

• Programmable from your PC/Mac/Linux

• Your limit is only your creativity!!

TERMINOLOGY

• I/O Board – main microcontroller

• Shield – add-on boards

• Sketch – the program

• Sensor – components (thermistors, etc.)

• Modules – serial data (GPS module, etc.)

14 current boards

ARDUINO I/O BOARDS

SHIELDS

SHIELDS

Touchscreen Shield

Wave Shield

Datalogging Shield

COMMUNICATION SHIELDS

Ethernet Shield GSM Shield Wifi Shield

Gas Sensor Temp & Humidity

Flex Sensor

Fingerprint Scanner

Geiger Counter

SENSORS

Photo/thermistor, infared, force sensitive resistor, Hall effect, Piezo, tilt sensor..

SENSORS

SKETCHES

Includes

Globals

void setup()

void loop()

HANDLING THE ARDUINO – HOW NOT TO DO IT!

Improper Handling - NEVER!!!

HANDLING THE ARDUINO – THE PROPER WAY

Proper Handling - by the edges!!!

TRY IT OUT 1: VERY SIMPLE LED BLINKING PROGRAM

int ledpin = 13; int del = 2000; void setup() { pinMode(ledpin, OUTPUT); } void loop() { digitalWrite(ledpin, HIGH); delay(del); digitalWrite(ledpin, LOW); delay(del); }

TRY IT OUT 1: VERY SIMPLE LED BLINKING PROGRAM

int ledpin = 13; int del = 2000; void setup() { pinMode(ledpin, OUTPUT); } void loop() { digitalWrite(ledpin, HIGH); delay(del); digitalWrite(ledpin, LOW); delay(del); }

Global variables Tells the Arduino that the LED is on pin 13 Delay between blinks as 2000 milliseconds Setup Tells the Arduino that pin 13 should be set as an output

Loop Sets pin 13 to provide 5 volts (HIGH) Delays for specified length of time (del) Sets pin 13 to provide 0 volts (LOW) Delays for specified length of time (del)

TRY IT OUT 1: VERY SIMPLE LED BLINKING PROGRAM

int ledpin = 13; int del = 2000; void setup() { pinMode(ledpin, OUTPUT); } void loop() { digitalWrite(ledpin, HIGH); delay(del); digitalWrite(ledpin, LOW); delay(del); }

TRY IT OUT 2: LIGHT DEPENDENT RESISTOR & LED

int LDR_Pin = A0; void setup(){ Serial.begin(9600); } void loop(){ int LDRReading = analogRead(LDR_Pin); Serial.println(LDRReading); delay(500); }

Serial This is a way by which your Arduino can “speak” with a computer Serial.begin opens the communications channel Serial.print/Serial.println will “print” a message

ADDING “IF” STATEMENTS

If/else Try to make your LED turn on when the light drops below a certain level… add this code to your sketch

if (LDRReading < 500) { digitalWrite(ledpin, HIGH); } else { digitalWrite(ledpin, LOW); }

TWEETING SENSORS 1: “SOMEONE’S RAIDING THE FRIDGE!”

WEATHER SENSOR NETWORKS

SENSOR NETWORK EXAMPLE: BIRMINGHAM • The primary focus of the Birmingham Urban Climate project is to

provide a series of demonstration sensor networks to measure air temperature

• The design is a nested network of sensors:

• ~30 full weather stations [coarse array]

• 131 air temperature sensors located in schools [wide array]

• ~100 air temperature sensors in the CBD (approx 50 sensors per square km) [fine array]

• Birmingham will become the most densely instrumented urban area in the world.

• The coarse array consists of ~30 full weather stations located across Birmingham.

• Urban equipment will be located in secure primary electricity substations (schools in areas without substations)

• Further 4 in the surrounding rural areas to record background conditions (i.e. Sandwell park, rural schools)

• Average spacing: 3km

N

COARSE ARRAY NETWORK

• A full suite of weather variables will be measured (air temperature, humidity, wind speed, wind direction, barometric pressure, precipitation, solar radiation).

• Data loggers (CR1000), communications and mountings (Campbell Scientific)

• Vaisala WXT520 – precipitation, wind speed, wind direction, temperature, relative humidity, pressure

• SKYE SKS1110 pyranometer

• Data Communication: GSM/GPRS

EQUIPMENT: WEATHER STATIONS

WIDE AREA ARRAY NETWORK • The wide area array consists

of 131 air temperature sensors located in schools

• Plus a few in ‘rural’ schools /parks/farms outside conurbation

• One per ONS medium super output area (MSOA)

• Average spacing: 1.5 km

• Data communication: WiFi via BGfL

EQUIPMENT: AIR TEMPERATURE SENSORS • The air temperature sensors

(thermistor) and radiation shield are a bespoke design from Aginova, USA.

• Small and inexpensive (approx. £87)

• Data is relayed via existing WiFi networks

• Battery life is estimated at 3 years (checked annually)

Aginova Micro

• ‘Low-Cost’ Thermistor Temperature probe (-30 to 70 °C)

• Precision 0.1 °C

• Accuracy ± 0.3 °C (20 °C)

• Stores data when |ΔTt – ΔTt-1| ≥ 0.1 °C

• Ability to store approx. 10 days data

• Secure Wifi data transmission back to server through school wireless network

• Server hosted software collects data from whole network and stores in database

TRY IT OUT 3: MINI WEATHER STATION

Open the “WeatherStation” sketch Upload to the Arduino Check out the “Serial Monitor”

TWEETING SENSORS 2: TEMPERATURE RECORDS

How could you use an “if” statement and some extra variables to record maximum and minimum temperatures How about printing these as messages? We could then tweet the messages (to cheat, look at weatherstation_minmax)

SOIL MOISTURE AND DROUGHT MONITORING NETWORKS

COMPONENTS OF A FAMINE EARLY WARNING SYSTEM

• Rainfall

• Soil moisture

• Crop condition

• Socio-economics

FEWS: RAINFALL

Global Telecommunication System

Rain-Gauge Network in Africa

-40

-20

0

20

40

-20 0 20 40 60

Longitude (deg)

Lati

tud

e (

deg

)

FEWS: RAINFALL

Spatial

Temporal

FEWS: VEGETATION CONDITION

FEWS: VEGETATION CONDITION

Spatial

Temporal

COMBINED DATASETS TO PREDICT FAMINE

Found at http://www.fews.net

SOIL MOISTURE FROM SPACE

TRY IT OUT 4: SOIL MOISTURE SENSOR int delaySecs = 5; void setup() { Serial.begin(9600); Serial.println("values: 0-1024 "); } void loop() { int raw_value = analogRead(A0); Serial.print(" "); Serial.println(raw_value); delay(1000*delaySecs); }

TRY IT OUT 5: CALIBRATED SOIL MOISTURE Convert raw output to voltage: volt_value = raw_value/1024*5 Convert voltage into moisture: moisture = (volt_value*4.44–0.5)/8.4*100 (to cheat, look at thetaprobe_calibrated)

TWEETING SENSORS 3: “WATER ME!”

How could you use an “if” statement and some extra variables to send a message when the soil is too dry?

THANK YOU

thomas.smith@kcl.ac.uk @DrTELS @KCLGEOGRAPHY facebook.com/KCLGeography K7.47 Office Hours: Mondays 16:00–17:00 Fridays 15:00–16:00