Originally posted by bernte_one
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IDX-PRO+VDI
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Originally posted by holyuser View PostYou must calculate the value of the resistor so that a fully charged battery at the entrance of the processor (pin 2) is 3.1738 volts, if VDD is exactly 5.000 volts
Apologies for a dumb question
If I put kits together what range of resistors should I supply for R2 ?
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Hi Holyuser,
What do you think about using one or several ports RA5/RA6/RA7 of the VDI µP to drive an audio stage ?
In exemple :
- below 0; all outputs set to zero.
- between 0 and 10 : RA5 set to 1
- between 11 and 30 : RA5 and RA6 set to 1
- etc ...
With a BCD decoder, you can even have up to 8 command lines ... meaning 8 differents tones !
It will be fine if the user can choose the number of thresholds and the values of them.
But it's just an idea ...
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Originally posted by hugo View PostHi Holyuser,
What do you think about using one or several ports RA5/RA6/RA7 of the VDI µP to drive an audio stage ?
In exemple :
- below 0; all outputs set to zero.
- between 0 and 10 : RA5 set to 1
- between 11 and 30 : RA5 and RA6 set to 1
- etc ...
With a BCD decoder, you can even have up to 8 command lines ... meaning 8 differents tones !
It will be fine if the user can choose the number of thresholds and the values of them.
But it's just an idea ...
- RA5 is input only, not possible to be used as output;
- RA6 and RA7 are reserved for external crystal resonator;
- RB0 is left free to be used for sound or TX drive, but that will be possible if PIC runs at 16 or 20 MHz.
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@Holyuser :
Ok, I understand.
So, I will say it differently ... Can we imagine a special version of the VDI, closed to the original schematic (without an external oscillator), able to pilot the audio ?
I mean, that RA6 & RA7 are reserved in my project, not generally.
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Originally posted by silverdog View PostApologies for a dumb question
If I put kits together what range of resistors should I supply for R2 ?
You can calculate it using the equation:
, where:
Vbat - is voltage of the fresh battery used (in Volts);
Vdd - is microcontroller voltage supply (in Volts);
R1 - in kOhms
In example, if You fresh battery is 12,6V and Vdd is exactly 5,0V and R1 = 20 kOm, then Your R2 must be:
You can use in this case 6,8 kOhm resistor, I think...
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Apologies, more dumb questions
I guess if your R2 value is incorrect the only consequence is inaccurate battery display ?
Could you explain the formula in steps I can't see how you get 6.7K from those values
On the Schematic there is no value for C1
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Originally posted by silverdog View PostI guess if your R2 value is incorrect the only consequence is inaccurate battery display ?
Could you explain the formula in steps I can't see how you get 6.7K from those values
1. we must firstly calculate 1024x12,6=12902,4 and 650x5=3250 ;
2. in the next step we find 12902,4/3250=3,97 (approximately) ;
3. next, we can find denominator as 3,97-1=2,97
4. finaly we divide 20 by 2,97 and voila! 20/2,97=6,734 (approximately)
On the Schematic there is no value for C1
I think, that something about 1nF would be good.
In my opinion, this capacitor is used to reduce the influence of cable.
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Hi to all
This link is my new vlf project. I used atmega8 microcontroller.
http://www.lugatek.com/forum/index.p...sg1416#msg1416
For only video:
http://www.youtube.com/watch?v=5CAqCVR03KE
I will share all documets of this project very soon too.
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