1. Environmental Monitoring with Arduino and Compatibles+

2. Takeaway Points Never more than three takeaway points!
Environmental monitoring is important.
Arduino is cheap and easy.
Small computers are fun.

3. Why? Why environmental monitoring? Repeatability (trends)
Water is shiny and deep
Why Arduino?
Small computers
One-chip micros (vs four-chip 4004)

4. The Arduino aka ATMega 168 An IDE written in JAVA plus gcc
A board exposing the ATMega168 pins

5. Integrated Dev Environment
IDE in Java
Edit
Compile
Download
Run

6. Water Temperature Thermistor changes resistance with temperature
Voltage divider turns resistance into voltage
Arduino measures voltage in middle

7. Stuff in the Water Stuff in the water is turbidity.
Not necessarily pollution – think tea with milk
Amount of light blocked is proportional to turbidity

8. Salinity (and other ions)
Electricity flows through ionized water
Metals carry electrons; ions have to move
Salt ionizes; but so do other things
Conductivity is inverse of salinity

9. Measuring Conductivity
Generate AC by flipping bits
int conduct(int high, int low) {
int otherbit;
DDRB = high | low;
// Generate AC on pins high and low
PORTB = low;
delay(5);
// wait 5 milliseconds for the analog-to-digital
// converter to settle after the last reading:
PORTB = high;
return analogRead(0); }

10. int conduct(int high, int low) {
int otherbit;
DDRB = high | low;
// Generate AC on pins 0 and 1
PORTB = low;
delay(5);
// wait 5 milliseconds for the analog-to-digital converter
// to settle after the last reading:
PORTB = high;
return analogRead(0); }

11. Takeaway Points Never more than three takeaway points!
Environmental monitoring is important.
Arduino is cheap and easy.
Small computers are fun.

12. No way have I said everything
Ask questions!
Ask more questions!
1/3rd of this talk is your questions!
Yer lettin' me off lightly if you don't ask questions!