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another thing, I get (sometimes) wired values on the receiver. I read the temperature good, but once in a whjile, I get 2 temperature reading on one line, other ime i get +200, etc...
does this have to do with the system being wireless, or the fact that my encoding technique is weak and prone to mistakes??
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HI I did the test , as I suspected, I get 0.7v all the time. So I caould put a few in a row to get a higher voltage difference and use that as a reference voltage.
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You could, but those diodes will vary in voltage with time, temperature, current flow, moon phases, etc, not by much, but they will change over time and temperature at least, and in series, they'd do nothing but get worse. Therefore, you're battery voltage reading will change accordingly, and probably screw you up in the long run. And you have to have X amount of current to even get the diodes to conduct. You might end up using more power than you would really want to just to get a reading.Originally Posted by lerameur
Have you been able to get the A/D working yet?
Like I said, spare pin to a resistor (probably 1K or so), other side of resistor to non-banded side of diode, banded side of diode to ground. Tap the non-banded side to your A/D port and take some readings with the battery hooked up as normal and A/D converter set up with Vref+ at Vdd and Vref- at Vss. If you're using the 10bit A/D, you should get a reading arorund 150-ish. Then as the battery wears down, the reading will go up. A reading of roughly 200 will mean a dead battery.
And, you can save the power to read the battery by change that 'spare pin' mentioned above to an input and shutting off the A/D module.
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ok , I have a problem now:
i wrote this program below, I configured so it read porta.0, but I get 0 output when I ground it and oscillation between 890 and to 900 when i put it to Vdd.
if I leave the program as is, and just put the input wire to portA.1 theni get 0 output when i groud the wire, and 1023 when I put it to Vdd.
Why am I getting a better result to a non configured port 6, at least i am ot calling this pin ??
my ADCON0 = %10000001 i believe this is for An0 to input
I am also trying to get two input for A/d , is that possible ?
'RECEIVE PIC
INCLUDE "modedefs.bas"
DEFINE OSC 20 'use external 20mhz crystal
DEFINE LCD_DREG PORTB ' Set LCD Data port
DEFINE LCD_DBIT 4 ' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_RSREG PORTB ' Set LCD Register Select port
DEFINE LCD_RSBIT 1 ' Set LCD Register Select bit
DEFINE LCD_EREG PORTB ' Set LCD Enable port
DEFINE LCD_EBIT 0 ' Set LCD Enable bit
DEFINE LCD_BITS 4 ' Set LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 2 ' Set number of lines on LCD
DEFINE LCD_COMMANDUS 2500
'DEFINE LCD_DATAUS 250
'DEFINE CHAR_PACING 2000
pause 1000
' Define ADCIN parameters
Define ADC_BITS 10 ' Set number of bits in result
Define ADC_CLOCK 3 ' Set clock source (3=rc)
Define ADC_SAMPLEUS 50 ' Set sampling time in uS
input1 var word : input2 var word
TRISA = %11111111 ' Set PORTA to all input
CMCON = 7
ANSEL = %00001100
ADCON1 = %10000010
ADCON0 = %10000001
Pause 500
loop: ADCIN porta.0, input1
Lcdout $fe, 1 ' Clear LCD
Lcdout "Value1: ", DEC input1 ' Display the decimal value
lcdout $FE,$C0, "Value2: ", dec input2
Pause 200
Goto loop
End
Also, what do you mean by : Spare pin to resistor ?
Last edited by lerameur; - 3rd January 2007 at 01:32.
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trying to get multiple input,but getting wrong values
loop:
ADCON0 = %10000001 ' Configure and turn on A/D Module
ADCIN porta.0, input1
pause 50
ADCON0 = %10001001 ' Configure and turn on A/D Module
ADCIN porta.1, input2
pause 50
Lcdout $fe, 1 ' Clear LCD
Lcdout "Value1: ", DEC input1 ' Display the decimal value
lcdout $FE,$C0, "Value2: ", dec input2
Pause 400
Goto loop
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Oscillation - I get that too on most everything I do on the A/D inputs (I don't know if it's a function of crappy circuit boards or bad design, doesn't matter to me anyways). You're probably going to want to do some sort of software averaging and/or put a capacitor across the input line to smooth it out a bit.
Spare pin on resistor - instead of putting the diode direct to battery power, thru a resistor to ground, you can intermittently power that diode thru a spare PIC output pin and save that power. Every little bit helps ya know.
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ok, but what about this loop here, can i do that, having multiple a/d conversion on one chip ?
loop:
ADCON0 = %10000001 ' Configure and turn on A/D Module
ADCIN porta.0, input1
pause 50
ADCON0 = %10001001 ' Configure and turn on A/D Module
ADCIN porta.1, input2
pause 50
From the definition of ADCON0, I can only choose one pin for A/D conversion. Maybe thats why it get mixed up .
Last edited by lerameur; - 3rd January 2007 at 21:39.
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You can do A/D on more than one pin, just not at the same time. I'm not sure why it didn't work for you in the one post. Maybe not waiting long enough between conversions and/or long enough between switching A/D channel assignment. I think you have to wait awhile, not only after the last conversion, but after you switch the channel, which ADCIN does for you. So, again, not sure. I'll think on it. Until then, double check your configuration, TRIS assignments, ADCON setup, etc.etc.
And you shouldn't have to use more than one channel for your project, unless I missed something there too...
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