day/night sensor

[grounded]

sayzer its was a 16-33k digi-key pvd-p8103-nd this was from a project that I did last year with a 12f629. the PBP manuel says to use a 5-50k &.1cap this had the greatest span and along with a 5k cal pot was still under the 50k as per the manuel. it worked but the pot had little effect. I just added this to the schematic I posted. which is the new project. this is the code I used with the 12f629.

Pot GPIO.4,100,DN
IF DN<140 Then
GoTo CHECKPIR
Else
GoTo MOVIE
EndIF
but If I can get a a greater span from the pot this project can be used for multiple things
thanks

[sayzer]

I can say that the POT command with LDR type of fast changing resistive devices is not quite precise.

Do you have any chance of using a PIC with ADC ?

Or have you tried your circuit with a PIC with ADC?


Also, POT command with 5K gives the best result as what I have experienced so far. Any value above 5K has not been working well for me (only with POT command though - even 10K was not good).

Also, why are you using a scale of 100? What was the reason?

[dhouston]

The PNA4603H (available from Digikey) outputs a voltage that is proportional to the light level. Its sensitivity and wavelength are similar to that of the human eye.

Use it on an ADC pin or use it on one input to the comparator and use a potentiometer on the other input to the comparator.

If you supply it with +5V using a PIC pin and use ADC, you can turn it off between readings to minimize battery drain.

[grounded]

thank you both
In my short time "playing" with the PIC I have not tried any of the adc stuff
the 16f676 is the sister chip to the 630 about the same but with adc
is this the way I need to go?

the 100 scale well I worked for 6 hr. before I got some thing that would work
(on the other project) started with 255 but did not have any luck ajusted both # and until 100 and it worked.