| ??? 05/21/06 06:31 Read: times |
#116771 - Try this Responding to: ???'s previous message |
Try this, It is not very accurate, but it works.
And it is cheap. To get another range change C1. Have a nice day. Robert.
+ 5V
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/ R1 100k
/<--+ LDR
/ |
/ |
+---+-------> I/O PORT
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= C1: 100 nF
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+ GND
; ***************************************
; * Get the pot value
; ***************************************
LDR BIT P3.3
LICHT DATA 5Eh
GETLIGHT: CLR LDR ; Discharge capacitor
MOV A,#100 ; Wait until empty
WACHT: DJNZ ACC,WACHT ; A is zero
SETB LDR ; C starts loading
LDR10: JB LDR,LDR20 ; It is high
INC A ; Count the time it takes
JNZ LDR10 ; to get high, Overflow
DEC A ; result is 255
LDR20: MOV LICHT,A ; Save value
RET
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| Topic | Author | Date |
| without adc | 01/01/70 00:00 | |
| ??? | 01/01/70 00:00 | |
| Yes, sort off | 01/01/70 00:00 | |
| slow inputs | 01/01/70 00:00 | |
| low cast (low speed ) ADC IC | 01/01/70 00:00 | |
| Low cost ADCs | 01/01/70 00:00 | |
| addjusting color also is posible whith . | 01/01/70 00:00 | |
| Just how cheap do you have to be? | 01/01/70 00:00 | |
| Specification! | 01/01/70 00:00 | |
blinkers | 01/01/70 00:00 | |
| Try this | 01/01/70 00:00 | |
| Thank you very much robert!!!!! | 01/01/70 00:00 | |
| a hint | 01/01/70 00:00 | |
| Beware! | 01/01/70 00:00 |