Final Design

Working Prototype of Wind-Clik Sensor

Requirements:

- Design a new sensor system that can detect wind speeds ranging from 2.2 m/s to 13.4 m/s (5-30mph)
- Allows user to easily:
  - Set the wind speed at which the sprinkler system turns off
  - Set the wind speed at which the sprinkler system resets
  - Manually override the sensor
- Prevents the sprinkler system from cycling On/Off Ability to Stand Up to a Five-Year Warranty in an Outdoor Environment

Wind Cups and Shaft

- Simplistic Wind Cup
- Threaded 4-40 Rod and Spacers to secure Magnet
- Ball Bearing at base of Shaft
- Sleeve Bearing at top of housing to constrain shaft in second locatio

Signal Generator

- Use of Magnet coupled to Rotating Shaft
- Placed near Copper Coil
- Produces AC Signal for Microcontroller
- Faraday’s Law: V=N∗∆(BA)/∆t
- Optimize Signal with Number of Turns (N), Magnet (B), and Area (A)
- Various Magnets range from .5299 to .7187 Teslas
- Number of Turns per Coil ≈ 2000

Electronics Design

Wind Cups and Shaft

Signal Generator

Microcontroller Code

'****************************************************************

'* Name : mae156b_ec_3.BAS *

'* Author : [select VIEW...EDITOR OPTIONS] *

'* Date : 3/10/2012 *

'* Version : 1.0 *

'* Notes : *

'* : *

'****************************************************************

DEFINE ADC_BITS 10 'number of bits in result

Define ADC_CLOCK 3 'set clock source (3=rc)

DEFINE ADC_SAMPLEUS 50 'Set sampling time in us

comp var GPIO.0 'input pin for the output of the comparator

relay1 var GPIO.5 'output to relay pin

relay2 var GPIO.4 'output to relay pin

a1 VAR word 'var to store data for counts of pulse

a2 VAR word 'var to store data for RPM of environment windspeed

p1 var word 'var to store shutoff pot value

p2 var word 'var to store reset pot value

dummy var word 'var for div32

user1 var word 'shutoff setting in RPM

user2 var word 'reset setting in RPM

init:

ADCON0.7=1 'right justified result (10bit)

TRISIO=%11001111 'Set direction of CH (1=input)

CMCON0=7 'comp off

ANSEL=%00110110 'Set AN0-3 as analog

'VRCON=%10100001 'sets vref on with low range 0000

pause 1000 'pause for 1s

relay1=0 'set output to relay pin1 to 0

relay2=1 'set output to relay pin2 to 1 to turn on sprinklers

pause 2000 'pause for 2s

relay2=0 'set output to realy pin2 to 0 to minimize power consumption

start:

count comp,10000,a1 'count pulses from comparator for 10s

a2=a1*6 'multiply by factor to obtain wind speed in RPM

ADCIN 1,p1 'store ADC Ch1 value to p1 var

dummy=756*p1 'store dummy value for div32

dummy=div32 1000 'div32 operation for dividing 32 bits of data

user1=dummy+4 'add the intercept to obtain shutoff in RPM

if a2>user1 THEN 'if env wind speed is > than shutoff

goto turnoff

ELSE 'otherwise

GOTO turnon

ENDIF

GOTO start

turnoff:

relay1=1 'set relay pin1 to 1

relay2=0 'set relay pin2 to 0 to turn off sprinkler system

pause 2000 'pause for 2s

relay1=0 'set relay pin1 to 0 to minimize power consumption

'sleep 5 'sleep for 5s

check:

count comp,10000,a1 'count pulses from comparator for 10s

a2=a1*6 'multiply by factor to obtain wind speed in RPM

ADCIN 2,p2 'store ADC Ch2 value to p2 var

dummy=756*p2 'store dummy value for div32

dummy=div32 1000 'div32 operation for dividing 32 bits of data

user2=dummy+4 'add the intercept to obtain shutoff in RPM

if a2<user2 THEN 'if env wind speed is > than shutoff

goto turnon

ELSE

GOTO turnoff

ENDIF

GOTO check

turnon:

relay1=0 'set relay pin1 to 0

relay2=1 'set relay pin2 to 1 to turn on sprinkler system

pause 2000 'pause for 2s

relay2=0 'set relay pin2 to 0 to minimize power consumption

'sleep 5 'sleep for 5s

goto start 'goto start

END 'end program