TABLE OF CONTENTS 



Page 



INTRODUCTION 1 



PURPOSE 2 



BRIEF DESCRIPTION OF FIELD OPERATION 2 



DESCRIPTION OF MAIN COMPONENTS 3 



Hygrothermograph 3 



Digital Rain Gauge Assembly 4 



Leaf Wetness Indicator (LWI) 5 



Instrumentation Shelter 7 



CONSTRUCTING THE 4-PEN ARM DESIGN 7 



Preparing the LWI and Rain-intensity Pen Arm Relays . . 7 



Constructing the LWI and Rain-intensity Pen Arms 8 



Constructing the Plexiglass Stage and 



Attaching the Pen Arm Relays 9 



Constructing the Leaf Wetness Indicator 10 



Wiring the Digital Rain Gauge and 



Rain-intensity Pen Arm Relay 21 



CONSTRUCTING THE 3-PEN ARM DESIGN 23 



Constructing the Plexiglass Mount 23 



Mounting the 12 V Solenoid to the 



Hygrothermograph Upright 24 



Correcting the Response of the 



Humidity- Adjustment Arm 25 



Wiring the Solenoid Unijunction Assembly and 

 Unijunction Accelerator Switch 25 



ATTACHING A SPORE TRAP TO 



THE INSTRUMENTATION 26 



11 



