Erratic analog inputs .

[timseven]

Thanks for your answer. I'll add the ADCON1 = 128. I think that's what I need.
The diodes puts out about 1 VDC max. at full exposure. I think it's enough to be amplified no? I'll do the changes and let you know. Thanks.

[timseven]

I added the ADCON1 right justified or bit 7 (1) with the four combination for bits 5-4. I got the same erratic result. Something that I want to point out is that the four channels show the same voltage no matter if they are grounded or not. Something here is odd. Any idea what should I do next? Thanks

[mackrackit]

When you measure the max voltage from the LEDs with a meter what do you have.

You will need an op amp like Charles said or move some things around and use the two VREFs. But that still might be a little tight with out an amp.

[Acetronics2]

Hi,

At first glance ...

Your Vref must be rock-stable ( Pic Decoupling ... What about ???) ... now result is +/- 1 digit ... = +/- 5 mv !!! ... a little HardWare scheme would be useful !!!

I'd recommend some external Vref ... if mV looked for !

Alain

[timseven]

Hi, I found a site that has a project that will help me setup mine. The project uses a potentiometer to vary the voltage to be read and display. It uses one port only ( portA.4) but for the test it’s good enough. I followed all the instructions and did the setup exactly as the program said. I copied the program and compiled it. The program describes that the displayed digital value will be from 0 to 1023. It worked as plan but the number displayed is a single digit not four as expected. This is the whole project site: C:\Documents and Settings\Dad\Desktop\mr k\adc2.pbp ,Please help me find what I am doing wrong. Thanks.

[mackrackit]

Hmmmmm.
For some reason I can not get into your "C" drive from here.
Could be a network problem.

Go over to rentron.com for some examples that work.
And what are your voltages?

[timseven]

I found the problem by chance. I mist the DEFINE ADC_BITS 10 that gives me the precision. Thanks any ways to Charles, Acetronics and Mackrackit that so gently help me figure it out. You guys out there are our best teachers ever. Thanks.