Reley help

pollack

i just need some help on programming a reley . first i have this

' {$STAMP BS2}
' {$PBASIC 2.5}
Photo·········· PIN···· 0

lightLevel····· CON···· 200

light·········· VAR···· Word
Main:
· GOSUB Get_Light
· DEBUG HOME, "Light = ", DEC light, CLREOL
·· IF (light > lightLevel) THEN
· HIGH 0
· PAUSE 500
· LOW 0
· END if
· GOTO Main
Get_Light:
· HIGH 2
· PAUSE 5
· RCTIME 2, 1, light

what i am doing is hooking a reley up to a office lamp the thing is it works it turns on but it·clicks on and off. what i am attempting to do is make one of those lights that flick on when it gets dark in the room. so i just want some help in making stop·flashing. so when i put my hand·over the photocell i want it to turn on, it works when i do that but i just want·the light to stay until i remove my hand. i have to do this with the reley.

Jon Williams

The program is cycling because you're turning the output on and then off -- so long as the light condition remains "dark" that will happen.· I made a small update to your program, and fixed a couple definitions to clarify things (you were mixing named constants and "magic numbers").


' {$STAMP BS2}
' {$PBASIC 2.5}

CdS······· PIN····0
Bulb······ PIN····1·········

BulbOn···· CON··· 200
BulbOff··· CON··· 150

light······VAR····Word
·
Main:
· GOSUB Get_Light
· DEBUG HOME, "Light = ", DEC light, CLREOL
··IF (light > BulbOn) THEN
··· HIGH Bulb
··· PAUSE 500
··· DO
····· GOSUB·Get_Light
····LOOP UNTIL (light < BulbOff)
··· LOW Bulb
··ENDIF
· GOTO Main
·
Get_Light:
· HIGH·CdS
· PAUSE 5
· RCTIME CdS, 1, light
· RETURN

Notice the span between BulbOn and BulbOff -- this gives the program a bit of hysteresis so that·the bulb·doesn't osciallate when the light level is right around the threshold.

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Jon Williams
Applications Engineer, Parallax