make a low voltage output from a PIC pin

hi,

for a science project, my son and i want to see what effects a low voltage will have on a goldfish. NOTE: this is LOW voltage and current, so no fish will be injured! i am using a simple voltage divider ckt to get 5.0V supply down below 1.0V steadystate.

my question is: how can i generate a low voltage that "flutters" off and on from a PIC pin? i'm guessing just do a PWM or SOUND output off the pin with another voltage divider? target voltage is 0.5 to 1.0V to keep it simple.

oh, and it must work underwater ;-)

any inputs are appreciated!

thanks
Pat

You may want to connect pwm pin of 628A with an led or fish frying probe to say PORTB.0.

Then have PWM set to a level that will give you the voltage you need.

PWM will run in background.

On the main program, you will have a simple flip flop loop turning PORTB.0 on and off.

When PORTB.0 is low, then PWM will be flowing through your probe (or led for test) to PORTB.0.

If you aso control flip flop frequency with a pot and also connect your pwm with another pot, then you can control both the voltage and the flip flop rate externally.

P.S. - Voltage reference feature of this chip can give you 1.25V on Vref pin.




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