1. Group Project: Water Turbidity Meter Group B

2. Outline Project Statement: “Design and construct a turbidity measuring and displaying device based on the HC08QY4 microcontroller” Integral components are the microcontroller mentioned above, an LDR, an LED, and the 7 segment display

3. What is turbidity? Turbidity is a “measure of the collective optical properties of a water sample that cause light to be scattered and absorbed rather than transmitted in straight lines (USGS 04/96).” The quantity of suspended solids in a water sample Indicates how potentially polluted a water sample is

4. Our design: LED functions as constant light source LED functions as constant light source LDR at set distance from LED measures light intensity LDR at set distance from LED measures light intensity Resistance of LDR varies according to intensity of light, providing an indication of water clarity Resistance of LDR varies according to intensity of light, providing an indication of water clarity Microcontroller records voltage drop over LDR every 15 seconds Microcontroller records voltage drop over LDR every 15 seconds Above measurement converted to a percentage of turbidity, displayed on 7 segment display Above measurement converted to a percentage of turbidity, displayed on 7 segment display 0% indicates perfect transparency (clean water); 100% is total light dispersion (very dirty water) 0% indicates perfect transparency (clean water); 100% is total light dispersion (very dirty water)

5. Basic Circuit

6. Basic process System is calibrated prior to first use System is calibrated prior to first use Turn LED on Turn LED on Measure voltage over LDR Measure voltage over LDR Convert voltage to percentage based on calibration Convert voltage to percentage based on calibration Output percentage to display, hold until next reading Output percentage to display, hold until next reading Wait 15 seconds Wait 15 seconds Start process again Start process again

7. To the future Find more information on turbidity meter design in general Find more information on turbidity meter design in general Adjust focus to now incorporate the specific software coding required for turbidity meter to function correctly Adjust focus to now incorporate the specific software coding required for turbidity meter to function correctly Develop code and produce functioning prototype circuit Develop code and produce functioning prototype circuit Test and adjust, trial and error Test and adjust, trial and error

8. Questions?